a66a23972d
Fix #146 Removed REDISMODULE_ prefixes from the core source code to align with the new SERVERMODULE_ naming convention. Added a new 'redismodule.h' header file to ensure full backward compatibility with existing modules. This compatibility layer maps all legacy REDISMODULE_ prefixed identifiers to their new SERVERMODULE_ equivalents, allowing existing Redis modules to function without modification. --------- Signed-off-by: Ping Xie <pingxie@google.com>
4242 lines
170 KiB
C
4242 lines
170 KiB
C
/* Asynchronous replication implementation.
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*
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* Copyright (c) 2009-2012, Salvatore Sanfilippo <antirez at gmail dot com>
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* All rights reserved.
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions are met:
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*
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* * Redistributions of source code must retain the above copyright notice,
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* this list of conditions and the following disclaimer.
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* * Redistributions in binary form must reproduce the above copyright
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* notice, this list of conditions and the following disclaimer in the
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* documentation and/or other materials provided with the distribution.
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* * Neither the name of Redis nor the names of its contributors may be used
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* to endorse or promote products derived from this software without
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* specific prior written permission.
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*
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* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
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* AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
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* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
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* ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE
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* LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
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* CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
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* SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
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* INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
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* CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
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* ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
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* POSSIBILITY OF SUCH DAMAGE.
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*/
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#include "server.h"
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#include "cluster.h"
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#include "bio.h"
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#include "functions.h"
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#include "connection.h"
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#include <memory.h>
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#include <sys/time.h>
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#include <unistd.h>
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#include <fcntl.h>
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#include <sys/socket.h>
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#include <sys/stat.h>
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void replicationDiscardCachedMaster(void);
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void replicationResurrectCachedMaster(connection *conn);
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void replicationSendAck(void);
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int replicaPutOnline(client *slave);
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void replicaStartCommandStream(client *slave);
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int cancelReplicationHandshake(int reconnect);
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/* We take a global flag to remember if this instance generated an RDB
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* because of replication, so that we can remove the RDB file in case
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* the instance is configured to have no persistence. */
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int RDBGeneratedByReplication = 0;
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/* --------------------------- Utility functions ---------------------------- */
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static ConnectionType *connTypeOfReplication(void) {
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if (server.tls_replication) {
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return connectionTypeTls();
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}
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return connectionTypeTcp();
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}
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/* Return the pointer to a string representing the slave ip:listening_port
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* pair. Mostly useful for logging, since we want to log a slave using its
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* IP address and its listening port which is more clear for the user, for
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* example: "Closing connection with replica 10.1.2.3:6380". */
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char *replicationGetSlaveName(client *c) {
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static char buf[NET_HOST_PORT_STR_LEN];
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char ip[NET_IP_STR_LEN];
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ip[0] = '\0';
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buf[0] = '\0';
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if (c->slave_addr ||
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connAddrPeerName(c->conn,ip,sizeof(ip),NULL) != -1)
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{
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char *addr = c->slave_addr ? c->slave_addr : ip;
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if (c->slave_listening_port)
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formatAddr(buf,sizeof(buf),addr,c->slave_listening_port);
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else
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snprintf(buf,sizeof(buf),"%s:<unknown-replica-port>",addr);
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} else {
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snprintf(buf,sizeof(buf),"client id #%llu",
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(unsigned long long) c->id);
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}
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return buf;
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}
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/* Plain unlink() can block for quite some time in order to actually apply
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* the file deletion to the filesystem. This call removes the file in a
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* background thread instead. We actually just do close() in the thread,
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* by using the fact that if there is another instance of the same file open,
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* the foreground unlink() will only remove the fs name, and deleting the
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* file's storage space will only happen once the last reference is lost. */
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int bg_unlink(const char *filename) {
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int fd = open(filename,O_RDONLY|O_NONBLOCK);
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if (fd == -1) {
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/* Can't open the file? Fall back to unlinking in the main thread. */
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return unlink(filename);
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} else {
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/* The following unlink() removes the name but doesn't free the
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* file contents because a process still has it open. */
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int retval = unlink(filename);
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if (retval == -1) {
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/* If we got an unlink error, we just return it, closing the
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* new reference we have to the file. */
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int old_errno = errno;
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close(fd); /* This would overwrite our errno. So we saved it. */
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errno = old_errno;
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return -1;
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}
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bioCreateCloseJob(fd, 0, 0);
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return 0; /* Success. */
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}
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}
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/* ---------------------------------- MASTER -------------------------------- */
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void createReplicationBacklog(void) {
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serverAssert(server.repl_backlog == NULL);
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server.repl_backlog = zmalloc(sizeof(replBacklog));
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server.repl_backlog->ref_repl_buf_node = NULL;
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server.repl_backlog->unindexed_count = 0;
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server.repl_backlog->blocks_index = raxNew();
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server.repl_backlog->histlen = 0;
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/* We don't have any data inside our buffer, but virtually the first
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* byte we have is the next byte that will be generated for the
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* replication stream. */
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server.repl_backlog->offset = server.master_repl_offset+1;
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}
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/* This function is called when the user modifies the replication backlog
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* size at runtime. It is up to the function to resize the buffer and setup it
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* so that it contains the same data as the previous one (possibly less data,
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* but the most recent bytes, or the same data and more free space in case the
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* buffer is enlarged). */
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void resizeReplicationBacklog(void) {
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if (server.repl_backlog_size < CONFIG_REPL_BACKLOG_MIN_SIZE)
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server.repl_backlog_size = CONFIG_REPL_BACKLOG_MIN_SIZE;
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if (server.repl_backlog)
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incrementalTrimReplicationBacklog(REPL_BACKLOG_TRIM_BLOCKS_PER_CALL);
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}
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void freeReplicationBacklog(void) {
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serverAssert(listLength(server.slaves) == 0);
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if (server.repl_backlog == NULL) return;
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/* Decrease the start buffer node reference count. */
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if (server.repl_backlog->ref_repl_buf_node) {
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replBufBlock *o = listNodeValue(
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server.repl_backlog->ref_repl_buf_node);
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serverAssert(o->refcount == 1); /* Last reference. */
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o->refcount--;
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}
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/* Replication buffer blocks are completely released when we free the
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* backlog, since the backlog is released only when there are no replicas
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* and the backlog keeps the last reference of all blocks. */
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freeReplicationBacklogRefMemAsync(server.repl_buffer_blocks,
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server.repl_backlog->blocks_index);
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resetReplicationBuffer();
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zfree(server.repl_backlog);
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server.repl_backlog = NULL;
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}
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/* To make search offset from replication buffer blocks quickly
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* when replicas ask partial resynchronization, we create one index
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* block every REPL_BACKLOG_INDEX_PER_BLOCKS blocks. */
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void createReplicationBacklogIndex(listNode *ln) {
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server.repl_backlog->unindexed_count++;
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if (server.repl_backlog->unindexed_count >= REPL_BACKLOG_INDEX_PER_BLOCKS) {
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replBufBlock *o = listNodeValue(ln);
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uint64_t encoded_offset = htonu64(o->repl_offset);
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raxInsert(server.repl_backlog->blocks_index,
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(unsigned char*)&encoded_offset, sizeof(uint64_t),
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ln, NULL);
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server.repl_backlog->unindexed_count = 0;
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}
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}
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/* Rebase replication buffer blocks' offset since the initial
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* setting offset starts from 0 when master restart. */
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void rebaseReplicationBuffer(long long base_repl_offset) {
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raxFree(server.repl_backlog->blocks_index);
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server.repl_backlog->blocks_index = raxNew();
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server.repl_backlog->unindexed_count = 0;
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listIter li;
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listNode *ln;
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listRewind(server.repl_buffer_blocks, &li);
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while ((ln = listNext(&li))) {
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replBufBlock *o = listNodeValue(ln);
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o->repl_offset += base_repl_offset;
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createReplicationBacklogIndex(ln);
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}
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}
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void resetReplicationBuffer(void) {
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server.repl_buffer_mem = 0;
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server.repl_buffer_blocks = listCreate();
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listSetFreeMethod(server.repl_buffer_blocks, (void (*)(void*))zfree);
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}
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int canFeedReplicaReplBuffer(client *replica) {
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/* Don't feed replicas that only want the RDB. */
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if (replica->flags & CLIENT_REPL_RDBONLY) return 0;
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/* Don't feed replicas that are still waiting for BGSAVE to start. */
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if (replica->replstate == SLAVE_STATE_WAIT_BGSAVE_START) return 0;
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return 1;
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}
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/* Similar with 'prepareClientToWrite', note that we must call this function
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* before feeding replication stream into global replication buffer, since
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* clientHasPendingReplies in prepareClientToWrite will access the global
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* replication buffer to make judgements. */
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int prepareReplicasToWrite(void) {
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listIter li;
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listNode *ln;
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int prepared = 0;
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listRewind(server.slaves,&li);
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while((ln = listNext(&li))) {
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client *slave = ln->value;
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if (!canFeedReplicaReplBuffer(slave)) continue;
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if (prepareClientToWrite(slave) == C_ERR) continue;
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prepared++;
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}
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return prepared;
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}
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/* Wrapper for feedReplicationBuffer() that takes Redis string objects
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* as input. */
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void feedReplicationBufferWithObject(robj *o) {
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char llstr[LONG_STR_SIZE];
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void *p;
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size_t len;
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if (o->encoding == OBJ_ENCODING_INT) {
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len = ll2string(llstr,sizeof(llstr),(long)o->ptr);
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p = llstr;
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} else {
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len = sdslen(o->ptr);
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p = o->ptr;
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}
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feedReplicationBuffer(p,len);
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}
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/* Generally, we only have one replication buffer block to trim when replication
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* backlog size exceeds our setting and no replica reference it. But if replica
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* clients disconnect, we need to free many replication buffer blocks that are
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* referenced. It would cost much time if there are a lots blocks to free, that
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* will freeze server, so we trim replication backlog incrementally. */
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void incrementalTrimReplicationBacklog(size_t max_blocks) {
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serverAssert(server.repl_backlog != NULL);
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size_t trimmed_blocks = 0;
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while (server.repl_backlog->histlen > server.repl_backlog_size &&
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trimmed_blocks < max_blocks)
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{
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/* We never trim backlog to less than one block. */
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if (listLength(server.repl_buffer_blocks) <= 1) break;
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/* Replicas increment the refcount of the first replication buffer block
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* they refer to, in that case, we don't trim the backlog even if
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* backlog_histlen exceeds backlog_size. This implicitly makes backlog
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* bigger than our setting, but makes the master accept partial resync as
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* much as possible. So that backlog must be the last reference of
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* replication buffer blocks. */
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listNode *first = listFirst(server.repl_buffer_blocks);
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serverAssert(first == server.repl_backlog->ref_repl_buf_node);
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replBufBlock *fo = listNodeValue(first);
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if (fo->refcount != 1) break;
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/* We don't try trim backlog if backlog valid size will be lessen than
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* setting backlog size once we release the first repl buffer block. */
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if (server.repl_backlog->histlen - (long long)fo->size <=
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server.repl_backlog_size) break;
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/* Decr refcount and release the first block later. */
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fo->refcount--;
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trimmed_blocks++;
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server.repl_backlog->histlen -= fo->size;
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/* Go to use next replication buffer block node. */
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listNode *next = listNextNode(first);
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server.repl_backlog->ref_repl_buf_node = next;
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serverAssert(server.repl_backlog->ref_repl_buf_node != NULL);
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/* Incr reference count to keep the new head node. */
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((replBufBlock *)listNodeValue(next))->refcount++;
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/* Remove the node in recorded blocks. */
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uint64_t encoded_offset = htonu64(fo->repl_offset);
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raxRemove(server.repl_backlog->blocks_index,
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(unsigned char*)&encoded_offset, sizeof(uint64_t), NULL);
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/* Delete the first node from global replication buffer. */
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serverAssert(fo->refcount == 0 && fo->used == fo->size);
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server.repl_buffer_mem -= (fo->size +
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sizeof(listNode) + sizeof(replBufBlock));
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listDelNode(server.repl_buffer_blocks, first);
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}
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/* Set the offset of the first byte we have in the backlog. */
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server.repl_backlog->offset = server.master_repl_offset -
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server.repl_backlog->histlen + 1;
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}
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/* Free replication buffer blocks that are referenced by this client. */
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void freeReplicaReferencedReplBuffer(client *replica) {
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if (replica->ref_repl_buf_node != NULL) {
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/* Decrease the start buffer node reference count. */
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replBufBlock *o = listNodeValue(replica->ref_repl_buf_node);
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serverAssert(o->refcount > 0);
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o->refcount--;
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incrementalTrimReplicationBacklog(REPL_BACKLOG_TRIM_BLOCKS_PER_CALL);
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}
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replica->ref_repl_buf_node = NULL;
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replica->ref_block_pos = 0;
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}
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/* Append bytes into the global replication buffer list, replication backlog and
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* all replica clients use replication buffers collectively, this function replace
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* 'addReply*', 'feedReplicationBacklog' for replicas and replication backlog,
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* First we add buffer into global replication buffer block list, and then
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* update replica / replication-backlog referenced node and block position. */
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void feedReplicationBuffer(char *s, size_t len) {
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static long long repl_block_id = 0;
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if (server.repl_backlog == NULL) return;
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while(len > 0) {
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size_t start_pos = 0; /* The position of referenced block to start sending. */
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listNode *start_node = NULL; /* Replica/backlog starts referenced node. */
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int add_new_block = 0; /* Create new block if current block is total used. */
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listNode *ln = listLast(server.repl_buffer_blocks);
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replBufBlock *tail = ln ? listNodeValue(ln) : NULL;
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/* Append to tail string when possible. */
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if (tail && tail->size > tail->used) {
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start_node = listLast(server.repl_buffer_blocks);
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start_pos = tail->used;
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/* Copy the part we can fit into the tail, and leave the rest for a
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* new node */
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size_t avail = tail->size - tail->used;
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size_t copy = (avail >= len) ? len : avail;
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memcpy(tail->buf + tail->used, s, copy);
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tail->used += copy;
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s += copy;
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len -= copy;
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server.master_repl_offset += copy;
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server.repl_backlog->histlen += copy;
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}
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if (len) {
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/* Create a new node, make sure it is allocated to at
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* least PROTO_REPLY_CHUNK_BYTES */
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size_t usable_size;
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/* Avoid creating nodes smaller than PROTO_REPLY_CHUNK_BYTES, so that we can append more data into them,
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* and also avoid creating nodes bigger than repl_backlog_size / 16, so that we won't have huge nodes that can't
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* trim when we only still need to hold a small portion from them. */
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size_t limit = max((size_t)server.repl_backlog_size / 16, (size_t)PROTO_REPLY_CHUNK_BYTES);
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size_t size = min(max(len, (size_t)PROTO_REPLY_CHUNK_BYTES), limit);
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tail = zmalloc_usable(size + sizeof(replBufBlock), &usable_size);
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/* Take over the allocation's internal fragmentation */
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tail->size = usable_size - sizeof(replBufBlock);
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size_t copy = (tail->size >= len) ? len : tail->size;
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tail->used = copy;
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tail->refcount = 0;
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tail->repl_offset = server.master_repl_offset + 1;
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tail->id = repl_block_id++;
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memcpy(tail->buf, s, copy);
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listAddNodeTail(server.repl_buffer_blocks, tail);
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/* We also count the list node memory into replication buffer memory. */
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server.repl_buffer_mem += (usable_size + sizeof(listNode));
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add_new_block = 1;
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if (start_node == NULL) {
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start_node = listLast(server.repl_buffer_blocks);
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start_pos = 0;
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}
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s += copy;
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len -= copy;
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server.master_repl_offset += copy;
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server.repl_backlog->histlen += copy;
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}
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/* For output buffer of replicas. */
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listIter li;
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listRewind(server.slaves,&li);
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while((ln = listNext(&li))) {
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client *slave = ln->value;
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if (!canFeedReplicaReplBuffer(slave)) continue;
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/* Update shared replication buffer start position. */
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if (slave->ref_repl_buf_node == NULL) {
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slave->ref_repl_buf_node = start_node;
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slave->ref_block_pos = start_pos;
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/* Only increase the start block reference count. */
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((replBufBlock *)listNodeValue(start_node))->refcount++;
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}
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/* Check output buffer limit only when add new block. */
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if (add_new_block) closeClientOnOutputBufferLimitReached(slave, 1);
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}
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/* For replication backlog */
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if (server.repl_backlog->ref_repl_buf_node == NULL) {
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server.repl_backlog->ref_repl_buf_node = start_node;
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/* Only increase the start block reference count. */
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((replBufBlock *)listNodeValue(start_node))->refcount++;
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/* Replication buffer must be empty before adding replication stream
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* into replication backlog. */
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serverAssert(add_new_block == 1 && start_pos == 0);
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}
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if (add_new_block) {
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createReplicationBacklogIndex(listLast(server.repl_buffer_blocks));
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/* It is important to trim after adding replication data to keep the backlog size close to
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* repl_backlog_size in the common case. We wait until we add a new block to avoid repeated
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* unnecessary trimming attempts when small amounts of data are added. See comments in
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* freeMemoryGetNotCountedMemory() for details on replication backlog memory tracking. */
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incrementalTrimReplicationBacklog(REPL_BACKLOG_TRIM_BLOCKS_PER_CALL);
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}
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}
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}
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/* Propagate write commands to replication stream.
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*
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* This function is used if the instance is a master: we use the commands
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* received by our clients in order to create the replication stream.
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* Instead if the instance is a replica and has sub-replicas attached, we use
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* replicationFeedStreamFromMasterStream() */
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void replicationFeedSlaves(list *slaves, int dictid, robj **argv, int argc) {
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int j, len;
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char llstr[LONG_STR_SIZE];
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|
|
/* In case we propagate a command that doesn't touch keys (PING, REPLCONF) we
|
|
* pass dbid=-1 that indicate there is no need to replicate `select` command. */
|
|
serverAssert(dictid == -1 || (dictid >= 0 && dictid < server.dbnum));
|
|
|
|
/* If the instance is not a top level master, return ASAP: we'll just proxy
|
|
* the stream of data we receive from our master instead, in order to
|
|
* propagate *identical* replication stream. In this way this slave can
|
|
* advertise the same replication ID as the master (since it shares the
|
|
* master replication history and has the same backlog and offsets). */
|
|
if (server.masterhost != NULL) return;
|
|
|
|
/* If there aren't slaves, and there is no backlog buffer to populate,
|
|
* we can return ASAP. */
|
|
if (server.repl_backlog == NULL && listLength(slaves) == 0) {
|
|
/* We increment the repl_offset anyway, since we use that for tracking AOF fsyncs
|
|
* even when there's no replication active. This code will not be reached if AOF
|
|
* is also disabled. */
|
|
server.master_repl_offset += 1;
|
|
return;
|
|
}
|
|
|
|
/* We can't have slaves attached and no backlog. */
|
|
serverAssert(!(listLength(slaves) != 0 && server.repl_backlog == NULL));
|
|
|
|
/* Must install write handler for all replicas first before feeding
|
|
* replication stream. */
|
|
prepareReplicasToWrite();
|
|
|
|
/* Send SELECT command to every slave if needed. */
|
|
if (dictid != -1 && server.slaveseldb != dictid) {
|
|
robj *selectcmd;
|
|
|
|
/* For a few DBs we have pre-computed SELECT command. */
|
|
if (dictid >= 0 && dictid < PROTO_SHARED_SELECT_CMDS) {
|
|
selectcmd = shared.select[dictid];
|
|
} else {
|
|
int dictid_len;
|
|
|
|
dictid_len = ll2string(llstr,sizeof(llstr),dictid);
|
|
selectcmd = createObject(OBJ_STRING,
|
|
sdscatprintf(sdsempty(),
|
|
"*2\r\n$6\r\nSELECT\r\n$%d\r\n%s\r\n",
|
|
dictid_len, llstr));
|
|
}
|
|
|
|
feedReplicationBufferWithObject(selectcmd);
|
|
|
|
if (dictid < 0 || dictid >= PROTO_SHARED_SELECT_CMDS)
|
|
decrRefCount(selectcmd);
|
|
|
|
server.slaveseldb = dictid;
|
|
}
|
|
|
|
/* Write the command to the replication buffer if any. */
|
|
char aux[LONG_STR_SIZE+3];
|
|
|
|
/* Add the multi bulk reply length. */
|
|
aux[0] = '*';
|
|
len = ll2string(aux+1,sizeof(aux)-1,argc);
|
|
aux[len+1] = '\r';
|
|
aux[len+2] = '\n';
|
|
feedReplicationBuffer(aux,len+3);
|
|
|
|
for (j = 0; j < argc; j++) {
|
|
long objlen = stringObjectLen(argv[j]);
|
|
|
|
/* We need to feed the buffer with the object as a bulk reply
|
|
* not just as a plain string, so create the $..CRLF payload len
|
|
* and add the final CRLF */
|
|
aux[0] = '$';
|
|
len = ll2string(aux+1,sizeof(aux)-1,objlen);
|
|
aux[len+1] = '\r';
|
|
aux[len+2] = '\n';
|
|
feedReplicationBuffer(aux,len+3);
|
|
feedReplicationBufferWithObject(argv[j]);
|
|
feedReplicationBuffer(aux+len+1,2);
|
|
}
|
|
}
|
|
|
|
/* This is a debugging function that gets called when we detect something
|
|
* wrong with the replication protocol: the goal is to peek into the
|
|
* replication backlog and show a few final bytes to make simpler to
|
|
* guess what kind of bug it could be. */
|
|
void showLatestBacklog(void) {
|
|
if (server.repl_backlog == NULL) return;
|
|
if (listLength(server.repl_buffer_blocks) == 0) return;
|
|
|
|
size_t dumplen = 256;
|
|
if (server.repl_backlog->histlen < (long long)dumplen)
|
|
dumplen = server.repl_backlog->histlen;
|
|
|
|
sds dump = sdsempty();
|
|
listNode *node = listLast(server.repl_buffer_blocks);
|
|
while(dumplen) {
|
|
if (node == NULL) break;
|
|
replBufBlock *o = listNodeValue(node);
|
|
size_t thislen = o->used >= dumplen ? dumplen : o->used;
|
|
sds head = sdscatrepr(sdsempty(), o->buf+o->used-thislen, thislen);
|
|
sds tmp = sdscatsds(head, dump);
|
|
sdsfree(dump);
|
|
dump = tmp;
|
|
dumplen -= thislen;
|
|
node = listPrevNode(node);
|
|
}
|
|
|
|
/* Finally log such bytes: this is vital debugging info to
|
|
* understand what happened. */
|
|
serverLog(LL_NOTICE,"Latest backlog is: '%s'", dump);
|
|
sdsfree(dump);
|
|
}
|
|
|
|
/* This function is used in order to proxy what we receive from our master
|
|
* to our sub-slaves. */
|
|
#include <ctype.h>
|
|
void replicationFeedStreamFromMasterStream(char *buf, size_t buflen) {
|
|
/* Debugging: this is handy to see the stream sent from master
|
|
* to slaves. Disabled with if(0). */
|
|
if (0) {
|
|
printf("%zu:",buflen);
|
|
for (size_t j = 0; j < buflen; j++) {
|
|
printf("%c", isprint(buf[j]) ? buf[j] : '.');
|
|
}
|
|
printf("\n");
|
|
}
|
|
|
|
/* There must be replication backlog if having attached slaves. */
|
|
if (listLength(server.slaves)) serverAssert(server.repl_backlog != NULL);
|
|
if (server.repl_backlog) {
|
|
/* Must install write handler for all replicas first before feeding
|
|
* replication stream. */
|
|
prepareReplicasToWrite();
|
|
feedReplicationBuffer(buf,buflen);
|
|
}
|
|
}
|
|
|
|
void replicationFeedMonitors(client *c, list *monitors, int dictid, robj **argv, int argc) {
|
|
/* Fast path to return if the monitors list is empty or the server is in loading. */
|
|
if (monitors == NULL || listLength(monitors) == 0 || server.loading) return;
|
|
listNode *ln;
|
|
listIter li;
|
|
int j;
|
|
sds cmdrepr = sdsnew("+");
|
|
robj *cmdobj;
|
|
struct timeval tv;
|
|
|
|
gettimeofday(&tv,NULL);
|
|
cmdrepr = sdscatprintf(cmdrepr,"%ld.%06ld ",(long)tv.tv_sec,(long)tv.tv_usec);
|
|
if (c->flags & CLIENT_SCRIPT) {
|
|
cmdrepr = sdscatprintf(cmdrepr,"[%d lua] ",dictid);
|
|
} else if (c->flags & CLIENT_UNIX_SOCKET) {
|
|
cmdrepr = sdscatprintf(cmdrepr,"[%d unix:%s] ",dictid,server.unixsocket);
|
|
} else {
|
|
cmdrepr = sdscatprintf(cmdrepr,"[%d %s] ",dictid,getClientPeerId(c));
|
|
}
|
|
|
|
for (j = 0; j < argc; j++) {
|
|
if (argv[j]->encoding == OBJ_ENCODING_INT) {
|
|
cmdrepr = sdscatprintf(cmdrepr, "\"%ld\"", (long)argv[j]->ptr);
|
|
} else {
|
|
cmdrepr = sdscatrepr(cmdrepr,(char*)argv[j]->ptr,
|
|
sdslen(argv[j]->ptr));
|
|
}
|
|
if (j != argc-1)
|
|
cmdrepr = sdscatlen(cmdrepr," ",1);
|
|
}
|
|
cmdrepr = sdscatlen(cmdrepr,"\r\n",2);
|
|
cmdobj = createObject(OBJ_STRING,cmdrepr);
|
|
|
|
listRewind(monitors,&li);
|
|
while((ln = listNext(&li))) {
|
|
client *monitor = ln->value;
|
|
addReply(monitor,cmdobj);
|
|
updateClientMemUsageAndBucket(monitor);
|
|
}
|
|
decrRefCount(cmdobj);
|
|
}
|
|
|
|
/* Feed the slave 'c' with the replication backlog starting from the
|
|
* specified 'offset' up to the end of the backlog. */
|
|
long long addReplyReplicationBacklog(client *c, long long offset) {
|
|
long long skip;
|
|
|
|
serverLog(LL_DEBUG, "[PSYNC] Replica request offset: %lld", offset);
|
|
|
|
if (server.repl_backlog->histlen == 0) {
|
|
serverLog(LL_DEBUG, "[PSYNC] Backlog history len is zero");
|
|
return 0;
|
|
}
|
|
|
|
serverLog(LL_DEBUG, "[PSYNC] Backlog size: %lld",
|
|
server.repl_backlog_size);
|
|
serverLog(LL_DEBUG, "[PSYNC] First byte: %lld",
|
|
server.repl_backlog->offset);
|
|
serverLog(LL_DEBUG, "[PSYNC] History len: %lld",
|
|
server.repl_backlog->histlen);
|
|
|
|
/* Compute the amount of bytes we need to discard. */
|
|
skip = offset - server.repl_backlog->offset;
|
|
serverLog(LL_DEBUG, "[PSYNC] Skipping: %lld", skip);
|
|
|
|
/* Iterate recorded blocks, quickly search the approximate node. */
|
|
listNode *node = NULL;
|
|
if (raxSize(server.repl_backlog->blocks_index) > 0) {
|
|
uint64_t encoded_offset = htonu64(offset);
|
|
raxIterator ri;
|
|
raxStart(&ri, server.repl_backlog->blocks_index);
|
|
raxSeek(&ri, ">", (unsigned char*)&encoded_offset, sizeof(uint64_t));
|
|
if (raxEOF(&ri)) {
|
|
/* No found, so search from the last recorded node. */
|
|
raxSeek(&ri, "$", NULL, 0);
|
|
raxPrev(&ri);
|
|
node = (listNode *)ri.data;
|
|
} else {
|
|
raxPrev(&ri); /* Skip the sought node. */
|
|
/* We should search from the prev node since the offset of current
|
|
* sought node exceeds searching offset. */
|
|
if (raxPrev(&ri))
|
|
node = (listNode *)ri.data;
|
|
else
|
|
node = server.repl_backlog->ref_repl_buf_node;
|
|
}
|
|
raxStop(&ri);
|
|
} else {
|
|
/* No recorded blocks, just from the start node to search. */
|
|
node = server.repl_backlog->ref_repl_buf_node;
|
|
}
|
|
|
|
/* Search the exact node. */
|
|
while (node != NULL) {
|
|
replBufBlock *o = listNodeValue(node);
|
|
if (o->repl_offset + (long long)o->used >= offset) break;
|
|
node = listNextNode(node);
|
|
}
|
|
serverAssert(node != NULL);
|
|
|
|
/* Install a writer handler first.*/
|
|
prepareClientToWrite(c);
|
|
/* Setting output buffer of the replica. */
|
|
replBufBlock *o = listNodeValue(node);
|
|
o->refcount++;
|
|
c->ref_repl_buf_node = node;
|
|
c->ref_block_pos = offset - o->repl_offset;
|
|
|
|
return server.repl_backlog->histlen - skip;
|
|
}
|
|
|
|
/* Return the offset to provide as reply to the PSYNC command received
|
|
* from the slave. The returned value is only valid immediately after
|
|
* the BGSAVE process started and before executing any other command
|
|
* from clients. */
|
|
long long getPsyncInitialOffset(void) {
|
|
return server.master_repl_offset;
|
|
}
|
|
|
|
/* Send a FULLRESYNC reply in the specific case of a full resynchronization,
|
|
* as a side effect setup the slave for a full sync in different ways:
|
|
*
|
|
* 1) Remember, into the slave client structure, the replication offset
|
|
* we sent here, so that if new slaves will later attach to the same
|
|
* background RDB saving process (by duplicating this client output
|
|
* buffer), we can get the right offset from this slave.
|
|
* 2) Set the replication state of the slave to WAIT_BGSAVE_END so that
|
|
* we start accumulating differences from this point.
|
|
* 3) Force the replication stream to re-emit a SELECT statement so
|
|
* the new slave incremental differences will start selecting the
|
|
* right database number.
|
|
*
|
|
* Normally this function should be called immediately after a successful
|
|
* BGSAVE for replication was started, or when there is one already in
|
|
* progress that we attached our slave to. */
|
|
int replicationSetupSlaveForFullResync(client *slave, long long offset) {
|
|
char buf[128];
|
|
int buflen;
|
|
|
|
slave->psync_initial_offset = offset;
|
|
slave->replstate = SLAVE_STATE_WAIT_BGSAVE_END;
|
|
/* We are going to accumulate the incremental changes for this
|
|
* slave as well. Set slaveseldb to -1 in order to force to re-emit
|
|
* a SELECT statement in the replication stream. */
|
|
server.slaveseldb = -1;
|
|
|
|
/* Don't send this reply to slaves that approached us with
|
|
* the old SYNC command. */
|
|
if (!(slave->flags & CLIENT_PRE_PSYNC)) {
|
|
buflen = snprintf(buf,sizeof(buf),"+FULLRESYNC %s %lld\r\n",
|
|
server.replid,offset);
|
|
if (connWrite(slave->conn,buf,buflen) != buflen) {
|
|
freeClientAsync(slave);
|
|
return C_ERR;
|
|
}
|
|
}
|
|
return C_OK;
|
|
}
|
|
|
|
/* This function handles the PSYNC command from the point of view of a
|
|
* master receiving a request for partial resynchronization.
|
|
*
|
|
* On success return C_OK, otherwise C_ERR is returned and we proceed
|
|
* with the usual full resync. */
|
|
int masterTryPartialResynchronization(client *c, long long psync_offset) {
|
|
long long psync_len;
|
|
char *master_replid = c->argv[1]->ptr;
|
|
char buf[128];
|
|
int buflen;
|
|
|
|
/* Is the replication ID of this master the same advertised by the wannabe
|
|
* slave via PSYNC? If the replication ID changed this master has a
|
|
* different replication history, and there is no way to continue.
|
|
*
|
|
* Note that there are two potentially valid replication IDs: the ID1
|
|
* and the ID2. The ID2 however is only valid up to a specific offset. */
|
|
if (strcasecmp(master_replid, server.replid) &&
|
|
(strcasecmp(master_replid, server.replid2) ||
|
|
psync_offset > server.second_replid_offset))
|
|
{
|
|
/* Replid "?" is used by slaves that want to force a full resync. */
|
|
if (master_replid[0] != '?') {
|
|
if (strcasecmp(master_replid, server.replid) &&
|
|
strcasecmp(master_replid, server.replid2))
|
|
{
|
|
serverLog(LL_NOTICE,"Partial resynchronization not accepted: "
|
|
"Replication ID mismatch (Replica asked for '%s', my "
|
|
"replication IDs are '%s' and '%s')",
|
|
master_replid, server.replid, server.replid2);
|
|
} else {
|
|
serverLog(LL_NOTICE,"Partial resynchronization not accepted: "
|
|
"Requested offset for second ID was %lld, but I can reply "
|
|
"up to %lld", psync_offset, server.second_replid_offset);
|
|
}
|
|
} else {
|
|
serverLog(LL_NOTICE,"Full resync requested by replica %s",
|
|
replicationGetSlaveName(c));
|
|
}
|
|
goto need_full_resync;
|
|
}
|
|
|
|
/* We still have the data our slave is asking for? */
|
|
if (!server.repl_backlog ||
|
|
psync_offset < server.repl_backlog->offset ||
|
|
psync_offset > (server.repl_backlog->offset + server.repl_backlog->histlen))
|
|
{
|
|
serverLog(LL_NOTICE,
|
|
"Unable to partial resync with replica %s for lack of backlog (Replica request was: %lld).", replicationGetSlaveName(c), psync_offset);
|
|
if (psync_offset > server.master_repl_offset) {
|
|
serverLog(LL_WARNING,
|
|
"Warning: replica %s tried to PSYNC with an offset that is greater than the master replication offset.", replicationGetSlaveName(c));
|
|
}
|
|
goto need_full_resync;
|
|
}
|
|
|
|
/* If we reached this point, we are able to perform a partial resync:
|
|
* 1) Set client state to make it a slave.
|
|
* 2) Inform the client we can continue with +CONTINUE
|
|
* 3) Send the backlog data (from the offset to the end) to the slave. */
|
|
c->flags |= CLIENT_SLAVE;
|
|
c->replstate = SLAVE_STATE_ONLINE;
|
|
c->repl_ack_time = server.unixtime;
|
|
c->repl_start_cmd_stream_on_ack = 0;
|
|
listAddNodeTail(server.slaves,c);
|
|
/* We can't use the connection buffers since they are used to accumulate
|
|
* new commands at this stage. But we are sure the socket send buffer is
|
|
* empty so this write will never fail actually. */
|
|
if (c->slave_capa & SLAVE_CAPA_PSYNC2) {
|
|
buflen = snprintf(buf,sizeof(buf),"+CONTINUE %s\r\n", server.replid);
|
|
} else {
|
|
buflen = snprintf(buf,sizeof(buf),"+CONTINUE\r\n");
|
|
}
|
|
if (connWrite(c->conn,buf,buflen) != buflen) {
|
|
freeClientAsync(c);
|
|
return C_OK;
|
|
}
|
|
psync_len = addReplyReplicationBacklog(c,psync_offset);
|
|
serverLog(LL_NOTICE,
|
|
"Partial resynchronization request from %s accepted. Sending %lld bytes of backlog starting from offset %lld.",
|
|
replicationGetSlaveName(c),
|
|
psync_len, psync_offset);
|
|
/* Note that we don't need to set the selected DB at server.slaveseldb
|
|
* to -1 to force the master to emit SELECT, since the slave already
|
|
* has this state from the previous connection with the master. */
|
|
|
|
refreshGoodSlavesCount();
|
|
|
|
/* Fire the replica change modules event. */
|
|
moduleFireServerEvent(VALKEYMODULE_EVENT_REPLICA_CHANGE,
|
|
VALKEYMODULE_SUBEVENT_REPLICA_CHANGE_ONLINE,
|
|
NULL);
|
|
|
|
return C_OK; /* The caller can return, no full resync needed. */
|
|
|
|
need_full_resync:
|
|
/* We need a full resync for some reason... Note that we can't
|
|
* reply to PSYNC right now if a full SYNC is needed. The reply
|
|
* must include the master offset at the time the RDB file we transfer
|
|
* is generated, so we need to delay the reply to that moment. */
|
|
return C_ERR;
|
|
}
|
|
|
|
/* Start a BGSAVE for replication goals, which is, selecting the disk or
|
|
* socket target depending on the configuration, and making sure that
|
|
* the script cache is flushed before to start.
|
|
*
|
|
* The mincapa argument is the bitwise AND among all the slaves capabilities
|
|
* of the slaves waiting for this BGSAVE, so represents the slave capabilities
|
|
* all the slaves support. Can be tested via SLAVE_CAPA_* macros.
|
|
*
|
|
* Side effects, other than starting a BGSAVE:
|
|
*
|
|
* 1) Handle the slaves in WAIT_START state, by preparing them for a full
|
|
* sync if the BGSAVE was successfully started, or sending them an error
|
|
* and dropping them from the list of slaves.
|
|
*
|
|
* 2) Flush the Lua scripting script cache if the BGSAVE was actually
|
|
* started.
|
|
*
|
|
* Returns C_OK on success or C_ERR otherwise. */
|
|
int startBgsaveForReplication(int mincapa, int req) {
|
|
int retval;
|
|
int socket_target = 0;
|
|
listIter li;
|
|
listNode *ln;
|
|
|
|
/* We use a socket target if slave can handle the EOF marker and we're configured to do diskless syncs.
|
|
* Note that in case we're creating a "filtered" RDB (functions-only, for example) we also force socket replication
|
|
* to avoid overwriting the snapshot RDB file with filtered data. */
|
|
socket_target = (server.repl_diskless_sync || req & SLAVE_REQ_RDB_MASK) && (mincapa & SLAVE_CAPA_EOF);
|
|
/* `SYNC` should have failed with error if we don't support socket and require a filter, assert this here */
|
|
serverAssert(socket_target || !(req & SLAVE_REQ_RDB_MASK));
|
|
|
|
serverLog(LL_NOTICE,"Starting BGSAVE for SYNC with target: %s",
|
|
socket_target ? "replicas sockets" : "disk");
|
|
|
|
rdbSaveInfo rsi, *rsiptr;
|
|
rsiptr = rdbPopulateSaveInfo(&rsi);
|
|
/* Only do rdbSave* when rsiptr is not NULL,
|
|
* otherwise slave will miss repl-stream-db. */
|
|
if (rsiptr) {
|
|
if (socket_target)
|
|
retval = rdbSaveToSlavesSockets(req,rsiptr);
|
|
else {
|
|
/* Keep the page cache since it'll get used soon */
|
|
retval = rdbSaveBackground(req,server.rdb_filename,rsiptr,RDBFLAGS_KEEP_CACHE);
|
|
}
|
|
} else {
|
|
serverLog(LL_WARNING,"BGSAVE for replication: replication information not available, can't generate the RDB file right now. Try later.");
|
|
retval = C_ERR;
|
|
}
|
|
|
|
/* If we succeeded to start a BGSAVE with disk target, let's remember
|
|
* this fact, so that we can later delete the file if needed. Note
|
|
* that we don't set the flag to 1 if the feature is disabled, otherwise
|
|
* it would never be cleared: the file is not deleted. This way if
|
|
* the user enables it later with CONFIG SET, we are fine. */
|
|
if (retval == C_OK && !socket_target && server.rdb_del_sync_files)
|
|
RDBGeneratedByReplication = 1;
|
|
|
|
/* If we failed to BGSAVE, remove the slaves waiting for a full
|
|
* resynchronization from the list of slaves, inform them with
|
|
* an error about what happened, close the connection ASAP. */
|
|
if (retval == C_ERR) {
|
|
serverLog(LL_WARNING,"BGSAVE for replication failed");
|
|
listRewind(server.slaves,&li);
|
|
while((ln = listNext(&li))) {
|
|
client *slave = ln->value;
|
|
|
|
if (slave->replstate == SLAVE_STATE_WAIT_BGSAVE_START) {
|
|
slave->replstate = REPL_STATE_NONE;
|
|
slave->flags &= ~CLIENT_SLAVE;
|
|
listDelNode(server.slaves,ln);
|
|
addReplyError(slave,
|
|
"BGSAVE failed, replication can't continue");
|
|
slave->flags |= CLIENT_CLOSE_AFTER_REPLY;
|
|
}
|
|
}
|
|
return retval;
|
|
}
|
|
|
|
/* If the target is socket, rdbSaveToSlavesSockets() already setup
|
|
* the slaves for a full resync. Otherwise for disk target do it now.*/
|
|
if (!socket_target) {
|
|
listRewind(server.slaves,&li);
|
|
while((ln = listNext(&li))) {
|
|
client *slave = ln->value;
|
|
|
|
if (slave->replstate == SLAVE_STATE_WAIT_BGSAVE_START) {
|
|
/* Check slave has the exact requirements */
|
|
if (slave->slave_req != req)
|
|
continue;
|
|
replicationSetupSlaveForFullResync(slave, getPsyncInitialOffset());
|
|
}
|
|
}
|
|
}
|
|
|
|
return retval;
|
|
}
|
|
|
|
/* SYNC and PSYNC command implementation. */
|
|
void syncCommand(client *c) {
|
|
/* ignore SYNC if already slave or in monitor mode */
|
|
if (c->flags & CLIENT_SLAVE) return;
|
|
|
|
/* Check if this is a failover request to a replica with the same replid and
|
|
* become a master if so. */
|
|
if (c->argc > 3 && !strcasecmp(c->argv[0]->ptr,"psync") &&
|
|
!strcasecmp(c->argv[3]->ptr,"failover"))
|
|
{
|
|
serverLog(LL_NOTICE, "Failover request received for replid %s.",
|
|
(unsigned char *)c->argv[1]->ptr);
|
|
if (!server.masterhost) {
|
|
addReplyError(c, "PSYNC FAILOVER can't be sent to a master.");
|
|
return;
|
|
}
|
|
|
|
if (!strcasecmp(c->argv[1]->ptr,server.replid)) {
|
|
replicationUnsetMaster();
|
|
sds client = catClientInfoString(sdsempty(),c);
|
|
serverLog(LL_NOTICE,
|
|
"MASTER MODE enabled (failover request from '%s')",client);
|
|
sdsfree(client);
|
|
} else {
|
|
addReplyError(c, "PSYNC FAILOVER replid must match my replid.");
|
|
return;
|
|
}
|
|
}
|
|
|
|
/* Don't let replicas sync with us while we're failing over */
|
|
if (server.failover_state != NO_FAILOVER) {
|
|
addReplyError(c,"-NOMASTERLINK Can't SYNC while failing over");
|
|
return;
|
|
}
|
|
|
|
/* Refuse SYNC requests if we are a slave but the link with our master
|
|
* is not ok... */
|
|
if (server.masterhost && server.repl_state != REPL_STATE_CONNECTED) {
|
|
addReplyError(c,"-NOMASTERLINK Can't SYNC while not connected with my master");
|
|
return;
|
|
}
|
|
|
|
/* SYNC can't be issued when the server has pending data to send to
|
|
* the client about already issued commands. We need a fresh reply
|
|
* buffer registering the differences between the BGSAVE and the current
|
|
* dataset, so that we can copy to other slaves if needed. */
|
|
if (clientHasPendingReplies(c)) {
|
|
addReplyError(c,"SYNC and PSYNC are invalid with pending output");
|
|
return;
|
|
}
|
|
|
|
/* Fail sync if slave doesn't support EOF capability but wants a filtered RDB. This is because we force filtered
|
|
* RDB's to be generated over a socket and not through a file to avoid conflicts with the snapshot files. Forcing
|
|
* use of a socket is handled, if needed, in `startBgsaveForReplication`. */
|
|
if (c->slave_req & SLAVE_REQ_RDB_MASK && !(c->slave_capa & SLAVE_CAPA_EOF)) {
|
|
addReplyError(c,"Filtered replica requires EOF capability");
|
|
return;
|
|
}
|
|
|
|
serverLog(LL_NOTICE,"Replica %s asks for synchronization",
|
|
replicationGetSlaveName(c));
|
|
|
|
/* Try a partial resynchronization if this is a PSYNC command.
|
|
* If it fails, we continue with usual full resynchronization, however
|
|
* when this happens replicationSetupSlaveForFullResync will replied
|
|
* with:
|
|
*
|
|
* +FULLRESYNC <replid> <offset>
|
|
*
|
|
* So the slave knows the new replid and offset to try a PSYNC later
|
|
* if the connection with the master is lost. */
|
|
if (!strcasecmp(c->argv[0]->ptr,"psync")) {
|
|
long long psync_offset;
|
|
if (getLongLongFromObjectOrReply(c, c->argv[2], &psync_offset, NULL) != C_OK) {
|
|
serverLog(LL_WARNING, "Replica %s asks for synchronization but with a wrong offset",
|
|
replicationGetSlaveName(c));
|
|
return;
|
|
}
|
|
|
|
if (masterTryPartialResynchronization(c, psync_offset) == C_OK) {
|
|
server.stat_sync_partial_ok++;
|
|
return; /* No full resync needed, return. */
|
|
} else {
|
|
char *master_replid = c->argv[1]->ptr;
|
|
|
|
/* Increment stats for failed PSYNCs, but only if the
|
|
* replid is not "?", as this is used by slaves to force a full
|
|
* resync on purpose when they are not able to partially
|
|
* resync. */
|
|
if (master_replid[0] != '?') server.stat_sync_partial_err++;
|
|
}
|
|
} else {
|
|
/* If a slave uses SYNC, we are dealing with an old implementation
|
|
* of the replication protocol (like redis-cli --slave). Flag the client
|
|
* so that we don't expect to receive REPLCONF ACK feedbacks. */
|
|
c->flags |= CLIENT_PRE_PSYNC;
|
|
}
|
|
|
|
/* Full resynchronization. */
|
|
server.stat_sync_full++;
|
|
|
|
/* Setup the slave as one waiting for BGSAVE to start. The following code
|
|
* paths will change the state if we handle the slave differently. */
|
|
c->replstate = SLAVE_STATE_WAIT_BGSAVE_START;
|
|
if (server.repl_disable_tcp_nodelay)
|
|
connDisableTcpNoDelay(c->conn); /* Non critical if it fails. */
|
|
c->repldbfd = -1;
|
|
c->flags |= CLIENT_SLAVE;
|
|
listAddNodeTail(server.slaves,c);
|
|
|
|
/* Create the replication backlog if needed. */
|
|
if (listLength(server.slaves) == 1 && server.repl_backlog == NULL) {
|
|
/* When we create the backlog from scratch, we always use a new
|
|
* replication ID and clear the ID2, since there is no valid
|
|
* past history. */
|
|
changeReplicationId();
|
|
clearReplicationId2();
|
|
createReplicationBacklog();
|
|
serverLog(LL_NOTICE,"Replication backlog created, my new "
|
|
"replication IDs are '%s' and '%s'",
|
|
server.replid, server.replid2);
|
|
}
|
|
|
|
/* CASE 1: BGSAVE is in progress, with disk target. */
|
|
if (server.child_type == CHILD_TYPE_RDB &&
|
|
server.rdb_child_type == RDB_CHILD_TYPE_DISK)
|
|
{
|
|
/* Ok a background save is in progress. Let's check if it is a good
|
|
* one for replication, i.e. if there is another slave that is
|
|
* registering differences since the server forked to save. */
|
|
client *slave;
|
|
listNode *ln;
|
|
listIter li;
|
|
|
|
listRewind(server.slaves,&li);
|
|
while((ln = listNext(&li))) {
|
|
slave = ln->value;
|
|
/* If the client needs a buffer of commands, we can't use
|
|
* a replica without replication buffer. */
|
|
if (slave->replstate == SLAVE_STATE_WAIT_BGSAVE_END &&
|
|
(!(slave->flags & CLIENT_REPL_RDBONLY) ||
|
|
(c->flags & CLIENT_REPL_RDBONLY)))
|
|
break;
|
|
}
|
|
/* To attach this slave, we check that it has at least all the
|
|
* capabilities of the slave that triggered the current BGSAVE
|
|
* and its exact requirements. */
|
|
if (ln && ((c->slave_capa & slave->slave_capa) == slave->slave_capa) &&
|
|
c->slave_req == slave->slave_req) {
|
|
/* Perfect, the server is already registering differences for
|
|
* another slave. Set the right state, and copy the buffer.
|
|
* We don't copy buffer if clients don't want. */
|
|
if (!(c->flags & CLIENT_REPL_RDBONLY))
|
|
copyReplicaOutputBuffer(c,slave);
|
|
replicationSetupSlaveForFullResync(c,slave->psync_initial_offset);
|
|
serverLog(LL_NOTICE,"Waiting for end of BGSAVE for SYNC");
|
|
} else {
|
|
/* No way, we need to wait for the next BGSAVE in order to
|
|
* register differences. */
|
|
serverLog(LL_NOTICE,"Can't attach the replica to the current BGSAVE. Waiting for next BGSAVE for SYNC");
|
|
}
|
|
|
|
/* CASE 2: BGSAVE is in progress, with socket target. */
|
|
} else if (server.child_type == CHILD_TYPE_RDB &&
|
|
server.rdb_child_type == RDB_CHILD_TYPE_SOCKET)
|
|
{
|
|
/* There is an RDB child process but it is writing directly to
|
|
* children sockets. We need to wait for the next BGSAVE
|
|
* in order to synchronize. */
|
|
serverLog(LL_NOTICE,"Current BGSAVE has socket target. Waiting for next BGSAVE for SYNC");
|
|
|
|
/* CASE 3: There is no BGSAVE is in progress. */
|
|
} else {
|
|
if (server.repl_diskless_sync && (c->slave_capa & SLAVE_CAPA_EOF) &&
|
|
server.repl_diskless_sync_delay)
|
|
{
|
|
/* Diskless replication RDB child is created inside
|
|
* replicationCron() since we want to delay its start a
|
|
* few seconds to wait for more slaves to arrive. */
|
|
serverLog(LL_NOTICE,"Delay next BGSAVE for diskless SYNC");
|
|
} else {
|
|
/* We don't have a BGSAVE in progress, let's start one. Diskless
|
|
* or disk-based mode is determined by replica's capacity. */
|
|
if (!hasActiveChildProcess()) {
|
|
startBgsaveForReplication(c->slave_capa, c->slave_req);
|
|
} else {
|
|
serverLog(LL_NOTICE,
|
|
"No BGSAVE in progress, but another BG operation is active. "
|
|
"BGSAVE for replication delayed");
|
|
}
|
|
}
|
|
}
|
|
return;
|
|
}
|
|
|
|
/* REPLCONF <option> <value> <option> <value> ...
|
|
* This command is used by a replica in order to configure the replication
|
|
* process before starting it with the SYNC command.
|
|
* This command is also used by a master in order to get the replication
|
|
* offset from a replica.
|
|
*
|
|
* Currently we support these options:
|
|
*
|
|
* - listening-port <port>
|
|
* - ip-address <ip>
|
|
* What is the listening ip and port of the Replica redis instance, so that
|
|
* the master can accurately lists replicas and their listening ports in the
|
|
* INFO output.
|
|
*
|
|
* - capa <eof|psync2>
|
|
* What is the capabilities of this instance.
|
|
* eof: supports EOF-style RDB transfer for diskless replication.
|
|
* psync2: supports PSYNC v2, so understands +CONTINUE <new repl ID>.
|
|
*
|
|
* - ack <offset> [fack <aofofs>]
|
|
* Replica informs the master the amount of replication stream that it
|
|
* processed so far, and optionally the replication offset fsynced to the AOF file.
|
|
* This special pattern doesn't reply to the caller.
|
|
*
|
|
* - getack <dummy>
|
|
* Unlike other subcommands, this is used by master to get the replication
|
|
* offset from a replica.
|
|
*
|
|
* - rdb-only <0|1>
|
|
* Only wants RDB snapshot without replication buffer.
|
|
*
|
|
* - rdb-filter-only <include-filters>
|
|
* Define "include" filters for the RDB snapshot. Currently we only support
|
|
* a single include filter: "functions". Passing an empty string "" will
|
|
* result in an empty RDB. */
|
|
void replconfCommand(client *c) {
|
|
int j;
|
|
|
|
if ((c->argc % 2) == 0) {
|
|
/* Number of arguments must be odd to make sure that every
|
|
* option has a corresponding value. */
|
|
addReplyErrorObject(c,shared.syntaxerr);
|
|
return;
|
|
}
|
|
|
|
/* Process every option-value pair. */
|
|
for (j = 1; j < c->argc; j+=2) {
|
|
if (!strcasecmp(c->argv[j]->ptr,"listening-port")) {
|
|
long port;
|
|
|
|
if ((getLongFromObjectOrReply(c,c->argv[j+1],
|
|
&port,NULL) != C_OK))
|
|
return;
|
|
c->slave_listening_port = port;
|
|
} else if (!strcasecmp(c->argv[j]->ptr,"ip-address")) {
|
|
sds addr = c->argv[j+1]->ptr;
|
|
if (sdslen(addr) < NET_HOST_STR_LEN) {
|
|
if (c->slave_addr) sdsfree(c->slave_addr);
|
|
c->slave_addr = sdsdup(addr);
|
|
} else {
|
|
addReplyErrorFormat(c,"REPLCONF ip-address provided by "
|
|
"replica instance is too long: %zd bytes", sdslen(addr));
|
|
return;
|
|
}
|
|
} else if (!strcasecmp(c->argv[j]->ptr,"capa")) {
|
|
/* Ignore capabilities not understood by this master. */
|
|
if (!strcasecmp(c->argv[j+1]->ptr,"eof"))
|
|
c->slave_capa |= SLAVE_CAPA_EOF;
|
|
else if (!strcasecmp(c->argv[j+1]->ptr,"psync2"))
|
|
c->slave_capa |= SLAVE_CAPA_PSYNC2;
|
|
} else if (!strcasecmp(c->argv[j]->ptr,"ack")) {
|
|
/* REPLCONF ACK is used by slave to inform the master the amount
|
|
* of replication stream that it processed so far. It is an
|
|
* internal only command that normal clients should never use. */
|
|
long long offset;
|
|
|
|
if (!(c->flags & CLIENT_SLAVE)) return;
|
|
if ((getLongLongFromObject(c->argv[j+1], &offset) != C_OK))
|
|
return;
|
|
if (offset > c->repl_ack_off)
|
|
c->repl_ack_off = offset;
|
|
if (c->argc > j+3 && !strcasecmp(c->argv[j+2]->ptr,"fack")) {
|
|
if ((getLongLongFromObject(c->argv[j+3], &offset) != C_OK))
|
|
return;
|
|
if (offset > c->repl_aof_off)
|
|
c->repl_aof_off = offset;
|
|
}
|
|
c->repl_ack_time = server.unixtime;
|
|
/* If this was a diskless replication, we need to really put
|
|
* the slave online when the first ACK is received (which
|
|
* confirms slave is online and ready to get more data). This
|
|
* allows for simpler and less CPU intensive EOF detection
|
|
* when streaming RDB files.
|
|
* There's a chance the ACK got to us before we detected that the
|
|
* bgsave is done (since that depends on cron ticks), so run a
|
|
* quick check first (instead of waiting for the next ACK. */
|
|
if (server.child_type == CHILD_TYPE_RDB && c->replstate == SLAVE_STATE_WAIT_BGSAVE_END)
|
|
checkChildrenDone();
|
|
if (c->repl_start_cmd_stream_on_ack && c->replstate == SLAVE_STATE_ONLINE)
|
|
replicaStartCommandStream(c);
|
|
/* Note: this command does not reply anything! */
|
|
return;
|
|
} else if (!strcasecmp(c->argv[j]->ptr,"getack")) {
|
|
/* REPLCONF GETACK is used in order to request an ACK ASAP
|
|
* to the slave. */
|
|
if (server.masterhost && server.master) replicationSendAck();
|
|
return;
|
|
} else if (!strcasecmp(c->argv[j]->ptr,"rdb-only")) {
|
|
/* REPLCONF RDB-ONLY is used to identify the client only wants
|
|
* RDB snapshot without replication buffer. */
|
|
long rdb_only = 0;
|
|
if (getRangeLongFromObjectOrReply(c,c->argv[j+1],
|
|
0,1,&rdb_only,NULL) != C_OK)
|
|
return;
|
|
if (rdb_only == 1) c->flags |= CLIENT_REPL_RDBONLY;
|
|
else c->flags &= ~CLIENT_REPL_RDBONLY;
|
|
} else if (!strcasecmp(c->argv[j]->ptr,"rdb-filter-only")) {
|
|
/* REPLCONFG RDB-FILTER-ONLY is used to define "include" filters
|
|
* for the RDB snapshot. Currently we only support a single
|
|
* include filter: "functions". In the future we may want to add
|
|
* other filters like key patterns, key types, non-volatile, module
|
|
* aux fields, ...
|
|
* We might want to add the complementing "RDB-FILTER-EXCLUDE" to
|
|
* filter out certain data. */
|
|
int filter_count, i;
|
|
sds *filters;
|
|
if (!(filters = sdssplitargs(c->argv[j+1]->ptr, &filter_count))) {
|
|
addReplyErrorFormat(c, "Missing rdb-filter-only values");
|
|
return;
|
|
}
|
|
/* By default filter out all parts of the rdb */
|
|
c->slave_req |= SLAVE_REQ_RDB_EXCLUDE_DATA;
|
|
c->slave_req |= SLAVE_REQ_RDB_EXCLUDE_FUNCTIONS;
|
|
for (i = 0; i < filter_count; i++) {
|
|
if (!strcasecmp(filters[i], "functions"))
|
|
c->slave_req &= ~SLAVE_REQ_RDB_EXCLUDE_FUNCTIONS;
|
|
else {
|
|
addReplyErrorFormat(c, "Unsupported rdb-filter-only option: %s", (char*)filters[i]);
|
|
sdsfreesplitres(filters, filter_count);
|
|
return;
|
|
}
|
|
}
|
|
sdsfreesplitres(filters, filter_count);
|
|
} else {
|
|
addReplyErrorFormat(c,"Unrecognized REPLCONF option: %s",
|
|
(char*)c->argv[j]->ptr);
|
|
return;
|
|
}
|
|
}
|
|
addReply(c,shared.ok);
|
|
}
|
|
|
|
/* This function puts a replica in the online state, and should be called just
|
|
* after a replica received the RDB file for the initial synchronization.
|
|
*
|
|
* It does a few things:
|
|
* 1) Put the slave in ONLINE state.
|
|
* 2) Update the count of "good replicas".
|
|
* 3) Trigger the module event.
|
|
*
|
|
* the return value indicates that the replica should be disconnected.
|
|
* */
|
|
int replicaPutOnline(client *slave) {
|
|
if (slave->flags & CLIENT_REPL_RDBONLY) {
|
|
slave->replstate = SLAVE_STATE_RDB_TRANSMITTED;
|
|
/* The client asked for RDB only so we should close it ASAP */
|
|
serverLog(LL_NOTICE,
|
|
"RDB transfer completed, rdb only replica (%s) should be disconnected asap",
|
|
replicationGetSlaveName(slave));
|
|
return 0;
|
|
}
|
|
slave->replstate = SLAVE_STATE_ONLINE;
|
|
slave->repl_ack_time = server.unixtime; /* Prevent false timeout. */
|
|
|
|
refreshGoodSlavesCount();
|
|
/* Fire the replica change modules event. */
|
|
moduleFireServerEvent(VALKEYMODULE_EVENT_REPLICA_CHANGE,
|
|
VALKEYMODULE_SUBEVENT_REPLICA_CHANGE_ONLINE,
|
|
NULL);
|
|
serverLog(LL_NOTICE,"Synchronization with replica %s succeeded",
|
|
replicationGetSlaveName(slave));
|
|
return 1;
|
|
}
|
|
|
|
/* This function should be called just after a replica received the RDB file
|
|
* for the initial synchronization, and we are finally ready to send the
|
|
* incremental stream of commands.
|
|
*
|
|
* It does a few things:
|
|
* 1) Close the replica's connection async if it doesn't need replication
|
|
* commands buffer stream, since it actually isn't a valid replica.
|
|
* 2) Make sure the writable event is re-installed, since when calling the SYNC
|
|
* command we had no replies and it was disabled, and then we could
|
|
* accumulate output buffer data without sending it to the replica so it
|
|
* won't get mixed with the RDB stream. */
|
|
void replicaStartCommandStream(client *slave) {
|
|
serverAssert(!(slave->flags & CLIENT_REPL_RDBONLY));
|
|
slave->repl_start_cmd_stream_on_ack = 0;
|
|
|
|
putClientInPendingWriteQueue(slave);
|
|
}
|
|
|
|
/* We call this function periodically to remove an RDB file that was
|
|
* generated because of replication, in an instance that is otherwise
|
|
* without any persistence. We don't want instances without persistence
|
|
* to take RDB files around, this violates certain policies in certain
|
|
* environments. */
|
|
void removeRDBUsedToSyncReplicas(void) {
|
|
/* If the feature is disabled, return ASAP but also clear the
|
|
* RDBGeneratedByReplication flag in case it was set. Otherwise if the
|
|
* feature was enabled, but gets disabled later with CONFIG SET, the
|
|
* flag may remain set to one: then next time the feature is re-enabled
|
|
* via CONFIG SET we have it set even if no RDB was generated
|
|
* because of replication recently. */
|
|
if (!server.rdb_del_sync_files) {
|
|
RDBGeneratedByReplication = 0;
|
|
return;
|
|
}
|
|
|
|
if (allPersistenceDisabled() && RDBGeneratedByReplication) {
|
|
client *slave;
|
|
listNode *ln;
|
|
listIter li;
|
|
|
|
int delrdb = 1;
|
|
listRewind(server.slaves,&li);
|
|
while((ln = listNext(&li))) {
|
|
slave = ln->value;
|
|
if (slave->replstate == SLAVE_STATE_WAIT_BGSAVE_START ||
|
|
slave->replstate == SLAVE_STATE_WAIT_BGSAVE_END ||
|
|
slave->replstate == SLAVE_STATE_SEND_BULK)
|
|
{
|
|
delrdb = 0;
|
|
break; /* No need to check the other replicas. */
|
|
}
|
|
}
|
|
if (delrdb) {
|
|
struct stat sb;
|
|
if (lstat(server.rdb_filename,&sb) != -1) {
|
|
RDBGeneratedByReplication = 0;
|
|
serverLog(LL_NOTICE,
|
|
"Removing the RDB file used to feed replicas "
|
|
"in a persistence-less instance");
|
|
bg_unlink(server.rdb_filename);
|
|
}
|
|
}
|
|
}
|
|
}
|
|
|
|
/* Close the repldbfd and reclaim the page cache if the client hold
|
|
* the last reference to replication DB */
|
|
void closeRepldbfd(client *myself) {
|
|
listNode *ln;
|
|
listIter li;
|
|
int reclaim = 1;
|
|
listRewind(server.slaves,&li);
|
|
while((ln = listNext(&li))) {
|
|
client *slave = ln->value;
|
|
if (slave != myself && slave->replstate == SLAVE_STATE_SEND_BULK) {
|
|
reclaim = 0;
|
|
break;
|
|
}
|
|
}
|
|
|
|
if (reclaim) {
|
|
bioCreateCloseJob(myself->repldbfd, 0, 1);
|
|
} else {
|
|
close(myself->repldbfd);
|
|
}
|
|
myself->repldbfd = -1;
|
|
}
|
|
|
|
void sendBulkToSlave(connection *conn) {
|
|
client *slave = connGetPrivateData(conn);
|
|
char buf[PROTO_IOBUF_LEN];
|
|
ssize_t nwritten, buflen;
|
|
|
|
/* Before sending the RDB file, we send the preamble as configured by the
|
|
* replication process. Currently the preamble is just the bulk count of
|
|
* the file in the form "$<length>\r\n". */
|
|
if (slave->replpreamble) {
|
|
nwritten = connWrite(conn,slave->replpreamble,sdslen(slave->replpreamble));
|
|
if (nwritten == -1) {
|
|
serverLog(LL_WARNING,
|
|
"Write error sending RDB preamble to replica: %s",
|
|
connGetLastError(conn));
|
|
freeClient(slave);
|
|
return;
|
|
}
|
|
atomicIncr(server.stat_net_repl_output_bytes, nwritten);
|
|
sdsrange(slave->replpreamble,nwritten,-1);
|
|
if (sdslen(slave->replpreamble) == 0) {
|
|
sdsfree(slave->replpreamble);
|
|
slave->replpreamble = NULL;
|
|
/* fall through sending data. */
|
|
} else {
|
|
return;
|
|
}
|
|
}
|
|
|
|
/* If the preamble was already transferred, send the RDB bulk data. */
|
|
lseek(slave->repldbfd,slave->repldboff,SEEK_SET);
|
|
buflen = read(slave->repldbfd,buf,PROTO_IOBUF_LEN);
|
|
if (buflen <= 0) {
|
|
serverLog(LL_WARNING,"Read error sending DB to replica: %s",
|
|
(buflen == 0) ? "premature EOF" : strerror(errno));
|
|
freeClient(slave);
|
|
return;
|
|
}
|
|
if ((nwritten = connWrite(conn,buf,buflen)) == -1) {
|
|
if (connGetState(conn) != CONN_STATE_CONNECTED) {
|
|
serverLog(LL_WARNING,"Write error sending DB to replica: %s",
|
|
connGetLastError(conn));
|
|
freeClient(slave);
|
|
}
|
|
return;
|
|
}
|
|
slave->repldboff += nwritten;
|
|
atomicIncr(server.stat_net_repl_output_bytes, nwritten);
|
|
if (slave->repldboff == slave->repldbsize) {
|
|
closeRepldbfd(slave);
|
|
connSetWriteHandler(slave->conn,NULL);
|
|
if (!replicaPutOnline(slave)) {
|
|
freeClient(slave);
|
|
return;
|
|
}
|
|
replicaStartCommandStream(slave);
|
|
}
|
|
}
|
|
|
|
/* Remove one write handler from the list of connections waiting to be writable
|
|
* during rdb pipe transfer. */
|
|
void rdbPipeWriteHandlerConnRemoved(struct connection *conn) {
|
|
if (!connHasWriteHandler(conn))
|
|
return;
|
|
connSetWriteHandler(conn, NULL);
|
|
client *slave = connGetPrivateData(conn);
|
|
slave->repl_last_partial_write = 0;
|
|
server.rdb_pipe_numconns_writing--;
|
|
/* if there are no more writes for now for this conn, or write error: */
|
|
if (server.rdb_pipe_numconns_writing == 0) {
|
|
if (aeCreateFileEvent(server.el, server.rdb_pipe_read, AE_READABLE, rdbPipeReadHandler,NULL) == AE_ERR) {
|
|
serverPanic("Unrecoverable error creating server.rdb_pipe_read file event.");
|
|
}
|
|
}
|
|
}
|
|
|
|
/* Called in diskless master during transfer of data from the rdb pipe, when
|
|
* the replica becomes writable again. */
|
|
void rdbPipeWriteHandler(struct connection *conn) {
|
|
serverAssert(server.rdb_pipe_bufflen>0);
|
|
client *slave = connGetPrivateData(conn);
|
|
ssize_t nwritten;
|
|
if ((nwritten = connWrite(conn, server.rdb_pipe_buff + slave->repldboff,
|
|
server.rdb_pipe_bufflen - slave->repldboff)) == -1)
|
|
{
|
|
if (connGetState(conn) == CONN_STATE_CONNECTED)
|
|
return; /* equivalent to EAGAIN */
|
|
serverLog(LL_WARNING,"Write error sending DB to replica: %s",
|
|
connGetLastError(conn));
|
|
freeClient(slave);
|
|
return;
|
|
} else {
|
|
slave->repldboff += nwritten;
|
|
atomicIncr(server.stat_net_repl_output_bytes, nwritten);
|
|
if (slave->repldboff < server.rdb_pipe_bufflen) {
|
|
slave->repl_last_partial_write = server.unixtime;
|
|
return; /* more data to write.. */
|
|
}
|
|
}
|
|
rdbPipeWriteHandlerConnRemoved(conn);
|
|
}
|
|
|
|
/* Called in diskless master, when there's data to read from the child's rdb pipe */
|
|
void rdbPipeReadHandler(struct aeEventLoop *eventLoop, int fd, void *clientData, int mask) {
|
|
UNUSED(mask);
|
|
UNUSED(clientData);
|
|
UNUSED(eventLoop);
|
|
int i;
|
|
if (!server.rdb_pipe_buff)
|
|
server.rdb_pipe_buff = zmalloc(PROTO_IOBUF_LEN);
|
|
serverAssert(server.rdb_pipe_numconns_writing==0);
|
|
|
|
while (1) {
|
|
server.rdb_pipe_bufflen = read(fd, server.rdb_pipe_buff, PROTO_IOBUF_LEN);
|
|
if (server.rdb_pipe_bufflen < 0) {
|
|
if (errno == EAGAIN || errno == EWOULDBLOCK)
|
|
return;
|
|
serverLog(LL_WARNING,"Diskless rdb transfer, read error sending DB to replicas: %s", strerror(errno));
|
|
for (i=0; i < server.rdb_pipe_numconns; i++) {
|
|
connection *conn = server.rdb_pipe_conns[i];
|
|
if (!conn)
|
|
continue;
|
|
client *slave = connGetPrivateData(conn);
|
|
freeClient(slave);
|
|
server.rdb_pipe_conns[i] = NULL;
|
|
}
|
|
killRDBChild();
|
|
return;
|
|
}
|
|
|
|
if (server.rdb_pipe_bufflen == 0) {
|
|
/* EOF - write end was closed. */
|
|
int stillUp = 0;
|
|
aeDeleteFileEvent(server.el, server.rdb_pipe_read, AE_READABLE);
|
|
for (i=0; i < server.rdb_pipe_numconns; i++)
|
|
{
|
|
connection *conn = server.rdb_pipe_conns[i];
|
|
if (!conn)
|
|
continue;
|
|
stillUp++;
|
|
}
|
|
serverLog(LL_NOTICE,"Diskless rdb transfer, done reading from pipe, %d replicas still up.", stillUp);
|
|
/* Now that the replicas have finished reading, notify the child that it's safe to exit.
|
|
* When the server detects the child has exited, it can mark the replica as online, and
|
|
* start streaming the replication buffers. */
|
|
close(server.rdb_child_exit_pipe);
|
|
server.rdb_child_exit_pipe = -1;
|
|
return;
|
|
}
|
|
|
|
int stillAlive = 0;
|
|
for (i=0; i < server.rdb_pipe_numconns; i++)
|
|
{
|
|
ssize_t nwritten;
|
|
connection *conn = server.rdb_pipe_conns[i];
|
|
if (!conn)
|
|
continue;
|
|
|
|
client *slave = connGetPrivateData(conn);
|
|
if ((nwritten = connWrite(conn, server.rdb_pipe_buff, server.rdb_pipe_bufflen)) == -1) {
|
|
if (connGetState(conn) != CONN_STATE_CONNECTED) {
|
|
serverLog(LL_WARNING,"Diskless rdb transfer, write error sending DB to replica: %s",
|
|
connGetLastError(conn));
|
|
freeClient(slave);
|
|
server.rdb_pipe_conns[i] = NULL;
|
|
continue;
|
|
}
|
|
/* An error and still in connected state, is equivalent to EAGAIN */
|
|
slave->repldboff = 0;
|
|
} else {
|
|
/* Note: when use diskless replication, 'repldboff' is the offset
|
|
* of 'rdb_pipe_buff' sent rather than the offset of entire RDB. */
|
|
slave->repldboff = nwritten;
|
|
atomicIncr(server.stat_net_repl_output_bytes, nwritten);
|
|
}
|
|
/* If we were unable to write all the data to one of the replicas,
|
|
* setup write handler (and disable pipe read handler, below) */
|
|
if (nwritten != server.rdb_pipe_bufflen) {
|
|
slave->repl_last_partial_write = server.unixtime;
|
|
server.rdb_pipe_numconns_writing++;
|
|
connSetWriteHandler(conn, rdbPipeWriteHandler);
|
|
}
|
|
stillAlive++;
|
|
}
|
|
|
|
if (stillAlive == 0) {
|
|
serverLog(LL_WARNING,"Diskless rdb transfer, last replica dropped, killing fork child.");
|
|
killRDBChild();
|
|
}
|
|
/* Remove the pipe read handler if at least one write handler was set. */
|
|
if (server.rdb_pipe_numconns_writing || stillAlive == 0) {
|
|
aeDeleteFileEvent(server.el, server.rdb_pipe_read, AE_READABLE);
|
|
break;
|
|
}
|
|
}
|
|
}
|
|
|
|
/* This function is called at the end of every background saving.
|
|
*
|
|
* The argument bgsaveerr is C_OK if the background saving succeeded
|
|
* otherwise C_ERR is passed to the function.
|
|
* The 'type' argument is the type of the child that terminated
|
|
* (if it had a disk or socket target). */
|
|
void updateSlavesWaitingBgsave(int bgsaveerr, int type) {
|
|
listNode *ln;
|
|
listIter li;
|
|
|
|
/* Note: there's a chance we got here from within the REPLCONF ACK command
|
|
* so we must avoid using freeClient, otherwise we'll crash on our way up. */
|
|
|
|
listRewind(server.slaves,&li);
|
|
while((ln = listNext(&li))) {
|
|
client *slave = ln->value;
|
|
|
|
if (slave->replstate == SLAVE_STATE_WAIT_BGSAVE_END) {
|
|
struct redis_stat buf;
|
|
|
|
if (bgsaveerr != C_OK) {
|
|
freeClientAsync(slave);
|
|
serverLog(LL_WARNING,"SYNC failed. BGSAVE child returned an error");
|
|
continue;
|
|
}
|
|
|
|
/* If this was an RDB on disk save, we have to prepare to send
|
|
* the RDB from disk to the slave socket. Otherwise if this was
|
|
* already an RDB -> Slaves socket transfer, used in the case of
|
|
* diskless replication, our work is trivial, we can just put
|
|
* the slave online. */
|
|
if (type == RDB_CHILD_TYPE_SOCKET) {
|
|
serverLog(LL_NOTICE,
|
|
"Streamed RDB transfer with replica %s succeeded (socket). Waiting for REPLCONF ACK from replica to enable streaming",
|
|
replicationGetSlaveName(slave));
|
|
/* Note: we wait for a REPLCONF ACK message from the replica in
|
|
* order to really put it online (install the write handler
|
|
* so that the accumulated data can be transferred). However
|
|
* we change the replication state ASAP, since our slave
|
|
* is technically online now.
|
|
*
|
|
* So things work like that:
|
|
*
|
|
* 1. We end transferring the RDB file via socket.
|
|
* 2. The replica is put ONLINE but the write handler
|
|
* is not installed.
|
|
* 3. The replica however goes really online, and pings us
|
|
* back via REPLCONF ACK commands.
|
|
* 4. Now we finally install the write handler, and send
|
|
* the buffers accumulated so far to the replica.
|
|
*
|
|
* But why we do that? Because the replica, when we stream
|
|
* the RDB directly via the socket, must detect the RDB
|
|
* EOF (end of file), that is a special random string at the
|
|
* end of the RDB (for streamed RDBs we don't know the length
|
|
* in advance). Detecting such final EOF string is much
|
|
* simpler and less CPU intensive if no more data is sent
|
|
* after such final EOF. So we don't want to glue the end of
|
|
* the RDB transfer with the start of the other replication
|
|
* data. */
|
|
if (!replicaPutOnline(slave)) {
|
|
freeClientAsync(slave);
|
|
continue;
|
|
}
|
|
slave->repl_start_cmd_stream_on_ack = 1;
|
|
} else {
|
|
if ((slave->repldbfd = open(server.rdb_filename,O_RDONLY)) == -1 ||
|
|
redis_fstat(slave->repldbfd,&buf) == -1) {
|
|
freeClientAsync(slave);
|
|
serverLog(LL_WARNING,"SYNC failed. Can't open/stat DB after BGSAVE: %s", strerror(errno));
|
|
continue;
|
|
}
|
|
slave->repldboff = 0;
|
|
slave->repldbsize = buf.st_size;
|
|
slave->replstate = SLAVE_STATE_SEND_BULK;
|
|
slave->replpreamble = sdscatprintf(sdsempty(),"$%lld\r\n",
|
|
(unsigned long long) slave->repldbsize);
|
|
|
|
connSetWriteHandler(slave->conn,NULL);
|
|
if (connSetWriteHandler(slave->conn,sendBulkToSlave) == C_ERR) {
|
|
freeClientAsync(slave);
|
|
continue;
|
|
}
|
|
}
|
|
}
|
|
}
|
|
}
|
|
|
|
/* Change the current instance replication ID with a new, random one.
|
|
* This will prevent successful PSYNCs between this master and other
|
|
* slaves, so the command should be called when something happens that
|
|
* alters the current story of the dataset. */
|
|
void changeReplicationId(void) {
|
|
getRandomHexChars(server.replid,CONFIG_RUN_ID_SIZE);
|
|
server.replid[CONFIG_RUN_ID_SIZE] = '\0';
|
|
}
|
|
|
|
/* Clear (invalidate) the secondary replication ID. This happens, for
|
|
* example, after a full resynchronization, when we start a new replication
|
|
* history. */
|
|
void clearReplicationId2(void) {
|
|
memset(server.replid2,'0',sizeof(server.replid));
|
|
server.replid2[CONFIG_RUN_ID_SIZE] = '\0';
|
|
server.second_replid_offset = -1;
|
|
}
|
|
|
|
/* Use the current replication ID / offset as secondary replication
|
|
* ID, and change the current one in order to start a new history.
|
|
* This should be used when an instance is switched from slave to master
|
|
* so that it can serve PSYNC requests performed using the master
|
|
* replication ID. */
|
|
void shiftReplicationId(void) {
|
|
memcpy(server.replid2,server.replid,sizeof(server.replid));
|
|
/* We set the second replid offset to the master offset + 1, since
|
|
* the slave will ask for the first byte it has not yet received, so
|
|
* we need to add one to the offset: for example if, as a slave, we are
|
|
* sure we have the same history as the master for 50 bytes, after we
|
|
* are turned into a master, we can accept a PSYNC request with offset
|
|
* 51, since the slave asking has the same history up to the 50th
|
|
* byte, and is asking for the new bytes starting at offset 51. */
|
|
server.second_replid_offset = server.master_repl_offset+1;
|
|
changeReplicationId();
|
|
serverLog(LL_NOTICE,"Setting secondary replication ID to %s, valid up to offset: %lld. New replication ID is %s", server.replid2, server.second_replid_offset, server.replid);
|
|
}
|
|
|
|
/* ----------------------------------- SLAVE -------------------------------- */
|
|
|
|
/* Returns 1 if the given replication state is a handshake state,
|
|
* 0 otherwise. */
|
|
int slaveIsInHandshakeState(void) {
|
|
return server.repl_state >= REPL_STATE_RECEIVE_PING_REPLY &&
|
|
server.repl_state <= REPL_STATE_RECEIVE_PSYNC_REPLY;
|
|
}
|
|
|
|
/* Avoid the master to detect the slave is timing out while loading the
|
|
* RDB file in initial synchronization. We send a single newline character
|
|
* that is valid protocol but is guaranteed to either be sent entirely or
|
|
* not, since the byte is indivisible.
|
|
*
|
|
* The function is called in two contexts: while we flush the current
|
|
* data with emptyDb(), and while we load the new data received as an
|
|
* RDB file from the master. */
|
|
void replicationSendNewlineToMaster(void) {
|
|
static time_t newline_sent;
|
|
if (time(NULL) != newline_sent) {
|
|
newline_sent = time(NULL);
|
|
/* Pinging back in this stage is best-effort. */
|
|
if (server.repl_transfer_s) connWrite(server.repl_transfer_s, "\n", 1);
|
|
}
|
|
}
|
|
|
|
/* Callback used by emptyDb() while flushing away old data to load
|
|
* the new dataset received by the master and by discardTempDb()
|
|
* after loading succeeded or failed. */
|
|
void replicationEmptyDbCallback(dict *d) {
|
|
UNUSED(d);
|
|
if (server.repl_state == REPL_STATE_TRANSFER)
|
|
replicationSendNewlineToMaster();
|
|
}
|
|
|
|
/* Once we have a link with the master and the synchronization was
|
|
* performed, this function materializes the master client we store
|
|
* at server.master, starting from the specified file descriptor. */
|
|
void replicationCreateMasterClient(connection *conn, int dbid) {
|
|
server.master = createClient(conn);
|
|
if (conn)
|
|
connSetReadHandler(server.master->conn, readQueryFromClient);
|
|
|
|
/**
|
|
* Important note:
|
|
* The CLIENT_DENY_BLOCKING flag is not, and should not, be set here.
|
|
* For commands like BLPOP, it makes no sense to block the master
|
|
* connection, and such blocking attempt will probably cause deadlock and
|
|
* break the replication. We consider such a thing as a bug because
|
|
* commands as BLPOP should never be sent on the replication link.
|
|
* A possible use-case for blocking the replication link is if a module wants
|
|
* to pass the execution to a background thread and unblock after the
|
|
* execution is done. This is the reason why we allow blocking the replication
|
|
* connection. */
|
|
server.master->flags |= CLIENT_MASTER;
|
|
|
|
server.master->authenticated = 1;
|
|
server.master->reploff = server.master_initial_offset;
|
|
server.master->read_reploff = server.master->reploff;
|
|
server.master->user = NULL; /* This client can do everything. */
|
|
memcpy(server.master->replid, server.master_replid,
|
|
sizeof(server.master_replid));
|
|
/* If master offset is set to -1, this master is old and is not
|
|
* PSYNC capable, so we flag it accordingly. */
|
|
if (server.master->reploff == -1)
|
|
server.master->flags |= CLIENT_PRE_PSYNC;
|
|
if (dbid != -1) selectDb(server.master,dbid);
|
|
}
|
|
|
|
/* This function will try to re-enable the AOF file after the
|
|
* master-replica synchronization: if it fails after multiple attempts
|
|
* the replica cannot be considered reliable and exists with an
|
|
* error. */
|
|
void restartAOFAfterSYNC(void) {
|
|
unsigned int tries, max_tries = 10;
|
|
for (tries = 0; tries < max_tries; ++tries) {
|
|
if (startAppendOnly() == C_OK) break;
|
|
serverLog(LL_WARNING,
|
|
"Failed enabling the AOF after successful master synchronization! "
|
|
"Trying it again in one second.");
|
|
sleep(1);
|
|
}
|
|
if (tries == max_tries) {
|
|
serverLog(LL_WARNING,
|
|
"FATAL: this replica instance finished the synchronization with "
|
|
"its master, but the AOF can't be turned on. Exiting now.");
|
|
exit(1);
|
|
}
|
|
}
|
|
|
|
static int useDisklessLoad(void) {
|
|
/* compute boolean decision to use diskless load */
|
|
int enabled = server.repl_diskless_load == REPL_DISKLESS_LOAD_SWAPDB ||
|
|
(server.repl_diskless_load == REPL_DISKLESS_LOAD_WHEN_DB_EMPTY && dbTotalServerKeyCount()==0);
|
|
|
|
if (enabled) {
|
|
/* Check all modules handle read errors, otherwise it's not safe to use diskless load. */
|
|
if (!moduleAllDatatypesHandleErrors()) {
|
|
serverLog(LL_NOTICE,
|
|
"Skipping diskless-load because there are modules that don't handle read errors.");
|
|
enabled = 0;
|
|
}
|
|
/* Check all modules handle async replication, otherwise it's not safe to use diskless load. */
|
|
else if (server.repl_diskless_load == REPL_DISKLESS_LOAD_SWAPDB && !moduleAllModulesHandleReplAsyncLoad()) {
|
|
serverLog(LL_NOTICE,
|
|
"Skipping diskless-load because there are modules that are not aware of async replication.");
|
|
enabled = 0;
|
|
}
|
|
}
|
|
return enabled;
|
|
}
|
|
|
|
/* Helper function for readSyncBulkPayload() to initialize tempDb
|
|
* before socket-loading the new db from master. The tempDb may be populated
|
|
* by swapMainDbWithTempDb or freed by disklessLoadDiscardTempDb later. */
|
|
redisDb *disklessLoadInitTempDb(void) {
|
|
return initTempDb();
|
|
}
|
|
|
|
/* Helper function for readSyncBulkPayload() to discard our tempDb
|
|
* when the loading succeeded or failed. */
|
|
void disklessLoadDiscardTempDb(redisDb *tempDb) {
|
|
discardTempDb(tempDb, replicationEmptyDbCallback);
|
|
}
|
|
|
|
/* If we know we got an entirely different data set from our master
|
|
* we have no way to incrementally feed our replicas after that.
|
|
* We want our replicas to resync with us as well, if we have any sub-replicas.
|
|
* This is useful on readSyncBulkPayload in places where we just finished transferring db. */
|
|
void replicationAttachToNewMaster(void) {
|
|
/* Replica starts to apply data from new master, we must discard the cached
|
|
* master structure. */
|
|
serverAssert(server.master == NULL);
|
|
replicationDiscardCachedMaster();
|
|
|
|
disconnectSlaves(); /* Force our replicas to resync with us as well. */
|
|
freeReplicationBacklog(); /* Don't allow our chained replicas to PSYNC. */
|
|
}
|
|
|
|
/* Asynchronously read the SYNC payload we receive from a master */
|
|
#define REPL_MAX_WRITTEN_BEFORE_FSYNC (1024*1024*8) /* 8 MB */
|
|
void readSyncBulkPayload(connection *conn) {
|
|
char buf[PROTO_IOBUF_LEN];
|
|
ssize_t nread, readlen, nwritten;
|
|
int use_diskless_load = useDisklessLoad();
|
|
redisDb *diskless_load_tempDb = NULL;
|
|
functionsLibCtx* temp_functions_lib_ctx = NULL;
|
|
int empty_db_flags = server.repl_slave_lazy_flush ? EMPTYDB_ASYNC :
|
|
EMPTYDB_NO_FLAGS;
|
|
off_t left;
|
|
|
|
/* Static vars used to hold the EOF mark, and the last bytes received
|
|
* from the server: when they match, we reached the end of the transfer. */
|
|
static char eofmark[CONFIG_RUN_ID_SIZE];
|
|
static char lastbytes[CONFIG_RUN_ID_SIZE];
|
|
static int usemark = 0;
|
|
|
|
/* If repl_transfer_size == -1 we still have to read the bulk length
|
|
* from the master reply. */
|
|
if (server.repl_transfer_size == -1) {
|
|
nread = connSyncReadLine(conn,buf,1024,server.repl_syncio_timeout*1000);
|
|
if (nread == -1) {
|
|
serverLog(LL_WARNING,
|
|
"I/O error reading bulk count from MASTER: %s",
|
|
connGetLastError(conn));
|
|
goto error;
|
|
} else {
|
|
/* nread here is returned by connSyncReadLine(), which calls syncReadLine() and
|
|
* convert "\r\n" to '\0' so 1 byte is lost. */
|
|
atomicIncr(server.stat_net_repl_input_bytes, nread+1);
|
|
}
|
|
|
|
if (buf[0] == '-') {
|
|
serverLog(LL_WARNING,
|
|
"MASTER aborted replication with an error: %s",
|
|
buf+1);
|
|
goto error;
|
|
} else if (buf[0] == '\0') {
|
|
/* At this stage just a newline works as a PING in order to take
|
|
* the connection live. So we refresh our last interaction
|
|
* timestamp. */
|
|
server.repl_transfer_lastio = server.unixtime;
|
|
return;
|
|
} else if (buf[0] != '$') {
|
|
serverLog(LL_WARNING,"Bad protocol from MASTER, the first byte is not '$' (we received '%s'), are you sure the host and port are right?", buf);
|
|
goto error;
|
|
}
|
|
|
|
/* There are two possible forms for the bulk payload. One is the
|
|
* usual $<count> bulk format. The other is used for diskless transfers
|
|
* when the master does not know beforehand the size of the file to
|
|
* transfer. In the latter case, the following format is used:
|
|
*
|
|
* $EOF:<40 bytes delimiter>
|
|
*
|
|
* At the end of the file the announced delimiter is transmitted. The
|
|
* delimiter is long and random enough that the probability of a
|
|
* collision with the actual file content can be ignored. */
|
|
if (strncmp(buf+1,"EOF:",4) == 0 && strlen(buf+5) >= CONFIG_RUN_ID_SIZE) {
|
|
usemark = 1;
|
|
memcpy(eofmark,buf+5,CONFIG_RUN_ID_SIZE);
|
|
memset(lastbytes,0,CONFIG_RUN_ID_SIZE);
|
|
/* Set any repl_transfer_size to avoid entering this code path
|
|
* at the next call. */
|
|
server.repl_transfer_size = 0;
|
|
serverLog(LL_NOTICE,
|
|
"MASTER <-> REPLICA sync: receiving streamed RDB from master with EOF %s",
|
|
use_diskless_load? "to parser":"to disk");
|
|
} else {
|
|
usemark = 0;
|
|
server.repl_transfer_size = strtol(buf+1,NULL,10);
|
|
serverLog(LL_NOTICE,
|
|
"MASTER <-> REPLICA sync: receiving %lld bytes from master %s",
|
|
(long long) server.repl_transfer_size,
|
|
use_diskless_load? "to parser":"to disk");
|
|
}
|
|
return;
|
|
}
|
|
|
|
if (!use_diskless_load) {
|
|
/* Read the data from the socket, store it to a file and search
|
|
* for the EOF. */
|
|
if (usemark) {
|
|
readlen = sizeof(buf);
|
|
} else {
|
|
left = server.repl_transfer_size - server.repl_transfer_read;
|
|
readlen = (left < (signed)sizeof(buf)) ? left : (signed)sizeof(buf);
|
|
}
|
|
|
|
nread = connRead(conn,buf,readlen);
|
|
if (nread <= 0) {
|
|
if (connGetState(conn) == CONN_STATE_CONNECTED) {
|
|
/* equivalent to EAGAIN */
|
|
return;
|
|
}
|
|
serverLog(LL_WARNING,"I/O error trying to sync with MASTER: %s",
|
|
(nread == -1) ? connGetLastError(conn) : "connection lost");
|
|
cancelReplicationHandshake(1);
|
|
return;
|
|
}
|
|
atomicIncr(server.stat_net_repl_input_bytes, nread);
|
|
|
|
/* When a mark is used, we want to detect EOF asap in order to avoid
|
|
* writing the EOF mark into the file... */
|
|
int eof_reached = 0;
|
|
|
|
if (usemark) {
|
|
/* Update the last bytes array, and check if it matches our
|
|
* delimiter. */
|
|
if (nread >= CONFIG_RUN_ID_SIZE) {
|
|
memcpy(lastbytes,buf+nread-CONFIG_RUN_ID_SIZE,
|
|
CONFIG_RUN_ID_SIZE);
|
|
} else {
|
|
int rem = CONFIG_RUN_ID_SIZE-nread;
|
|
memmove(lastbytes,lastbytes+nread,rem);
|
|
memcpy(lastbytes+rem,buf,nread);
|
|
}
|
|
if (memcmp(lastbytes,eofmark,CONFIG_RUN_ID_SIZE) == 0)
|
|
eof_reached = 1;
|
|
}
|
|
|
|
/* Update the last I/O time for the replication transfer (used in
|
|
* order to detect timeouts during replication), and write what we
|
|
* got from the socket to the dump file on disk. */
|
|
server.repl_transfer_lastio = server.unixtime;
|
|
if ((nwritten = write(server.repl_transfer_fd,buf,nread)) != nread) {
|
|
serverLog(LL_WARNING,
|
|
"Write error or short write writing to the DB dump file "
|
|
"needed for MASTER <-> REPLICA synchronization: %s",
|
|
(nwritten == -1) ? strerror(errno) : "short write");
|
|
goto error;
|
|
}
|
|
server.repl_transfer_read += nread;
|
|
|
|
/* Delete the last 40 bytes from the file if we reached EOF. */
|
|
if (usemark && eof_reached) {
|
|
if (ftruncate(server.repl_transfer_fd,
|
|
server.repl_transfer_read - CONFIG_RUN_ID_SIZE) == -1)
|
|
{
|
|
serverLog(LL_WARNING,
|
|
"Error truncating the RDB file received from the master "
|
|
"for SYNC: %s", strerror(errno));
|
|
goto error;
|
|
}
|
|
}
|
|
|
|
/* Sync data on disk from time to time, otherwise at the end of the
|
|
* transfer we may suffer a big delay as the memory buffers are copied
|
|
* into the actual disk. */
|
|
if (server.repl_transfer_read >=
|
|
server.repl_transfer_last_fsync_off + REPL_MAX_WRITTEN_BEFORE_FSYNC)
|
|
{
|
|
off_t sync_size = server.repl_transfer_read -
|
|
server.repl_transfer_last_fsync_off;
|
|
rdb_fsync_range(server.repl_transfer_fd,
|
|
server.repl_transfer_last_fsync_off, sync_size);
|
|
server.repl_transfer_last_fsync_off += sync_size;
|
|
}
|
|
|
|
/* Check if the transfer is now complete */
|
|
if (!usemark) {
|
|
if (server.repl_transfer_read == server.repl_transfer_size)
|
|
eof_reached = 1;
|
|
}
|
|
|
|
/* If the transfer is yet not complete, we need to read more, so
|
|
* return ASAP and wait for the handler to be called again. */
|
|
if (!eof_reached) return;
|
|
}
|
|
|
|
/* We reach this point in one of the following cases:
|
|
*
|
|
* 1. The replica is using diskless replication, that is, it reads data
|
|
* directly from the socket to the Redis memory, without using
|
|
* a temporary RDB file on disk. In that case we just block and
|
|
* read everything from the socket.
|
|
*
|
|
* 2. Or when we are done reading from the socket to the RDB file, in
|
|
* such case we want just to read the RDB file in memory. */
|
|
|
|
/* We need to stop any AOF rewriting child before flushing and parsing
|
|
* the RDB, otherwise we'll create a copy-on-write disaster. */
|
|
if (server.aof_state != AOF_OFF) stopAppendOnly();
|
|
/* Also try to stop save RDB child before flushing and parsing the RDB:
|
|
* 1. Ensure background save doesn't overwrite synced data after being loaded.
|
|
* 2. Avoid copy-on-write disaster. */
|
|
if (server.child_type == CHILD_TYPE_RDB) {
|
|
if (!use_diskless_load) {
|
|
serverLog(LL_NOTICE,
|
|
"Replica is about to load the RDB file received from the "
|
|
"master, but there is a pending RDB child running. "
|
|
"Killing process %ld and removing its temp file to avoid "
|
|
"any race",
|
|
(long) server.child_pid);
|
|
}
|
|
killRDBChild();
|
|
}
|
|
|
|
if (use_diskless_load && server.repl_diskless_load == REPL_DISKLESS_LOAD_SWAPDB) {
|
|
/* Initialize empty tempDb dictionaries. */
|
|
diskless_load_tempDb = disklessLoadInitTempDb();
|
|
temp_functions_lib_ctx = functionsLibCtxCreate();
|
|
|
|
moduleFireServerEvent(VALKEYMODULE_EVENT_REPL_ASYNC_LOAD,
|
|
VALKEYMODULE_SUBEVENT_REPL_ASYNC_LOAD_STARTED,
|
|
NULL);
|
|
} else {
|
|
replicationAttachToNewMaster();
|
|
|
|
serverLog(LL_NOTICE, "MASTER <-> REPLICA sync: Flushing old data");
|
|
emptyData(-1,empty_db_flags,replicationEmptyDbCallback);
|
|
}
|
|
|
|
/* Before loading the DB into memory we need to delete the readable
|
|
* handler, otherwise it will get called recursively since
|
|
* rdbLoad() will call the event loop to process events from time to
|
|
* time for non blocking loading. */
|
|
connSetReadHandler(conn, NULL);
|
|
|
|
serverLog(LL_NOTICE, "MASTER <-> REPLICA sync: Loading DB in memory");
|
|
rdbSaveInfo rsi = RDB_SAVE_INFO_INIT;
|
|
if (use_diskless_load) {
|
|
rio rdb;
|
|
redisDb *dbarray;
|
|
functionsLibCtx* functions_lib_ctx;
|
|
int asyncLoading = 0;
|
|
|
|
if (server.repl_diskless_load == REPL_DISKLESS_LOAD_SWAPDB) {
|
|
/* Async loading means we continue serving read commands during full resync, and
|
|
* "swap" the new db with the old db only when loading is done.
|
|
* It is enabled only on SWAPDB diskless replication when master replication ID hasn't changed,
|
|
* because in that state the old content of the db represents a different point in time of the same
|
|
* data set we're currently receiving from the master. */
|
|
if (memcmp(server.replid, server.master_replid, CONFIG_RUN_ID_SIZE) == 0) {
|
|
asyncLoading = 1;
|
|
}
|
|
dbarray = diskless_load_tempDb;
|
|
functions_lib_ctx = temp_functions_lib_ctx;
|
|
} else {
|
|
dbarray = server.db;
|
|
functions_lib_ctx = functionsLibCtxGetCurrent();
|
|
functionsLibCtxClear(functions_lib_ctx);
|
|
}
|
|
|
|
rioInitWithConn(&rdb,conn,server.repl_transfer_size);
|
|
|
|
/* Put the socket in blocking mode to simplify RDB transfer.
|
|
* We'll restore it when the RDB is received. */
|
|
connBlock(conn);
|
|
connRecvTimeout(conn, server.repl_timeout*1000);
|
|
startLoading(server.repl_transfer_size, RDBFLAGS_REPLICATION, asyncLoading);
|
|
|
|
int loadingFailed = 0;
|
|
rdbLoadingCtx loadingCtx = { .dbarray = dbarray, .functions_lib_ctx = functions_lib_ctx };
|
|
if (rdbLoadRioWithLoadingCtx(&rdb,RDBFLAGS_REPLICATION,&rsi,&loadingCtx) != C_OK) {
|
|
/* RDB loading failed. */
|
|
serverLog(LL_WARNING,
|
|
"Failed trying to load the MASTER synchronization DB "
|
|
"from socket, check server logs.");
|
|
loadingFailed = 1;
|
|
} else if (usemark) {
|
|
/* Verify the end mark is correct. */
|
|
if (!rioRead(&rdb, buf, CONFIG_RUN_ID_SIZE) ||
|
|
memcmp(buf, eofmark, CONFIG_RUN_ID_SIZE) != 0)
|
|
{
|
|
serverLog(LL_WARNING, "Replication stream EOF marker is broken");
|
|
loadingFailed = 1;
|
|
}
|
|
}
|
|
|
|
if (loadingFailed) {
|
|
stopLoading(0);
|
|
cancelReplicationHandshake(1);
|
|
rioFreeConn(&rdb, NULL);
|
|
|
|
if (server.repl_diskless_load == REPL_DISKLESS_LOAD_SWAPDB) {
|
|
/* Discard potentially partially loaded tempDb. */
|
|
moduleFireServerEvent(VALKEYMODULE_EVENT_REPL_ASYNC_LOAD,
|
|
VALKEYMODULE_SUBEVENT_REPL_ASYNC_LOAD_ABORTED,
|
|
NULL);
|
|
|
|
disklessLoadDiscardTempDb(diskless_load_tempDb);
|
|
functionsLibCtxFree(temp_functions_lib_ctx);
|
|
serverLog(LL_NOTICE, "MASTER <-> REPLICA sync: Discarding temporary DB in background");
|
|
} else {
|
|
/* Remove the half-loaded data in case we started with an empty replica. */
|
|
emptyData(-1,empty_db_flags,replicationEmptyDbCallback);
|
|
}
|
|
|
|
/* Note that there's no point in restarting the AOF on SYNC
|
|
* failure, it'll be restarted when sync succeeds or the replica
|
|
* gets promoted. */
|
|
return;
|
|
}
|
|
|
|
/* RDB loading succeeded if we reach this point. */
|
|
if (server.repl_diskless_load == REPL_DISKLESS_LOAD_SWAPDB) {
|
|
/* We will soon swap main db with tempDb and replicas will start
|
|
* to apply data from new master, we must discard the cached
|
|
* master structure and force resync of sub-replicas. */
|
|
replicationAttachToNewMaster();
|
|
|
|
serverLog(LL_NOTICE, "MASTER <-> REPLICA sync: Swapping active DB with loaded DB");
|
|
swapMainDbWithTempDb(diskless_load_tempDb);
|
|
|
|
/* swap existing functions ctx with the temporary one */
|
|
functionsLibCtxSwapWithCurrent(temp_functions_lib_ctx);
|
|
|
|
moduleFireServerEvent(VALKEYMODULE_EVENT_REPL_ASYNC_LOAD,
|
|
VALKEYMODULE_SUBEVENT_REPL_ASYNC_LOAD_COMPLETED,
|
|
NULL);
|
|
|
|
/* Delete the old db as it's useless now. */
|
|
disklessLoadDiscardTempDb(diskless_load_tempDb);
|
|
serverLog(LL_NOTICE, "MASTER <-> REPLICA sync: Discarding old DB in background");
|
|
}
|
|
|
|
/* Inform about db change, as replication was diskless and didn't cause a save. */
|
|
server.dirty++;
|
|
|
|
stopLoading(1);
|
|
|
|
/* Cleanup and restore the socket to the original state to continue
|
|
* with the normal replication. */
|
|
rioFreeConn(&rdb, NULL);
|
|
connNonBlock(conn);
|
|
connRecvTimeout(conn,0);
|
|
} else {
|
|
|
|
/* Make sure the new file (also used for persistence) is fully synced
|
|
* (not covered by earlier calls to rdb_fsync_range). */
|
|
if (fsync(server.repl_transfer_fd) == -1) {
|
|
serverLog(LL_WARNING,
|
|
"Failed trying to sync the temp DB to disk in "
|
|
"MASTER <-> REPLICA synchronization: %s",
|
|
strerror(errno));
|
|
cancelReplicationHandshake(1);
|
|
return;
|
|
}
|
|
|
|
/* Rename rdb like renaming rewrite aof asynchronously. */
|
|
int old_rdb_fd = open(server.rdb_filename,O_RDONLY|O_NONBLOCK);
|
|
if (rename(server.repl_transfer_tmpfile,server.rdb_filename) == -1) {
|
|
serverLog(LL_WARNING,
|
|
"Failed trying to rename the temp DB into %s in "
|
|
"MASTER <-> REPLICA synchronization: %s",
|
|
server.rdb_filename, strerror(errno));
|
|
cancelReplicationHandshake(1);
|
|
if (old_rdb_fd != -1) close(old_rdb_fd);
|
|
return;
|
|
}
|
|
/* Close old rdb asynchronously. */
|
|
if (old_rdb_fd != -1) bioCreateCloseJob(old_rdb_fd, 0, 0);
|
|
|
|
/* Sync the directory to ensure rename is persisted */
|
|
if (fsyncFileDir(server.rdb_filename) == -1) {
|
|
serverLog(LL_WARNING,
|
|
"Failed trying to sync DB directory %s in "
|
|
"MASTER <-> REPLICA synchronization: %s",
|
|
server.rdb_filename, strerror(errno));
|
|
cancelReplicationHandshake(1);
|
|
return;
|
|
}
|
|
|
|
if (rdbLoad(server.rdb_filename,&rsi,RDBFLAGS_REPLICATION) != RDB_OK) {
|
|
serverLog(LL_WARNING,
|
|
"Failed trying to load the MASTER synchronization "
|
|
"DB from disk, check server logs.");
|
|
cancelReplicationHandshake(1);
|
|
if (server.rdb_del_sync_files && allPersistenceDisabled()) {
|
|
serverLog(LL_NOTICE,"Removing the RDB file obtained from "
|
|
"the master. This replica has persistence "
|
|
"disabled");
|
|
bg_unlink(server.rdb_filename);
|
|
}
|
|
/* Note that there's no point in restarting the AOF on sync failure,
|
|
it'll be restarted when sync succeeds or replica promoted. */
|
|
return;
|
|
}
|
|
|
|
/* Cleanup. */
|
|
if (server.rdb_del_sync_files && allPersistenceDisabled()) {
|
|
serverLog(LL_NOTICE,"Removing the RDB file obtained from "
|
|
"the master. This replica has persistence "
|
|
"disabled");
|
|
bg_unlink(server.rdb_filename);
|
|
}
|
|
|
|
zfree(server.repl_transfer_tmpfile);
|
|
close(server.repl_transfer_fd);
|
|
server.repl_transfer_fd = -1;
|
|
server.repl_transfer_tmpfile = NULL;
|
|
}
|
|
|
|
/* Final setup of the connected slave <- master link */
|
|
replicationCreateMasterClient(server.repl_transfer_s,rsi.repl_stream_db);
|
|
server.repl_state = REPL_STATE_CONNECTED;
|
|
server.repl_down_since = 0;
|
|
|
|
/* Fire the master link modules event. */
|
|
moduleFireServerEvent(VALKEYMODULE_EVENT_PRIMARY_LINK_CHANGE,
|
|
VALKEYMODULE_SUBEVENT_PRIMARY_LINK_UP,
|
|
NULL);
|
|
|
|
/* After a full resynchronization we use the replication ID and
|
|
* offset of the master. The secondary ID / offset are cleared since
|
|
* we are starting a new history. */
|
|
memcpy(server.replid,server.master->replid,sizeof(server.replid));
|
|
server.master_repl_offset = server.master->reploff;
|
|
clearReplicationId2();
|
|
|
|
/* Let's create the replication backlog if needed. Slaves need to
|
|
* accumulate the backlog regardless of the fact they have sub-slaves
|
|
* or not, in order to behave correctly if they are promoted to
|
|
* masters after a failover. */
|
|
if (server.repl_backlog == NULL) createReplicationBacklog();
|
|
serverLog(LL_NOTICE, "MASTER <-> REPLICA sync: Finished with success");
|
|
|
|
if (server.supervised_mode == SUPERVISED_SYSTEMD) {
|
|
redisCommunicateSystemd("STATUS=MASTER <-> REPLICA sync: Finished with success. Ready to accept connections in read-write mode.\n");
|
|
}
|
|
|
|
/* Send the initial ACK immediately to put this replica in online state. */
|
|
if (usemark) replicationSendAck();
|
|
|
|
/* Restart the AOF subsystem now that we finished the sync. This
|
|
* will trigger an AOF rewrite, and when done will start appending
|
|
* to the new file. */
|
|
if (server.aof_enabled) restartAOFAfterSYNC();
|
|
return;
|
|
|
|
error:
|
|
cancelReplicationHandshake(1);
|
|
return;
|
|
}
|
|
|
|
char *receiveSynchronousResponse(connection *conn) {
|
|
char buf[256];
|
|
/* Read the reply from the server. */
|
|
if (connSyncReadLine(conn,buf,sizeof(buf),server.repl_syncio_timeout*1000) == -1)
|
|
{
|
|
serverLog(LL_WARNING, "Failed to read response from the server: %s", connGetLastError(conn));
|
|
return NULL;
|
|
}
|
|
server.repl_transfer_lastio = server.unixtime;
|
|
return sdsnew(buf);
|
|
}
|
|
|
|
/* Send a pre-formatted multi-bulk command to the connection. */
|
|
char* sendCommandRaw(connection *conn, sds cmd) {
|
|
if (connSyncWrite(conn,cmd,sdslen(cmd),server.repl_syncio_timeout*1000) == -1) {
|
|
return sdscatprintf(sdsempty(),"-Writing to master: %s",
|
|
connGetLastError(conn));
|
|
}
|
|
return NULL;
|
|
}
|
|
|
|
/* Compose a multi-bulk command and send it to the connection.
|
|
* Used to send AUTH and REPLCONF commands to the master before starting the
|
|
* replication.
|
|
*
|
|
* Takes a list of char* arguments, terminated by a NULL argument.
|
|
*
|
|
* The command returns an sds string representing the result of the
|
|
* operation. On error the first byte is a "-".
|
|
*/
|
|
char *sendCommand(connection *conn, ...) {
|
|
va_list ap;
|
|
sds cmd = sdsempty();
|
|
sds cmdargs = sdsempty();
|
|
size_t argslen = 0;
|
|
char *arg;
|
|
|
|
/* Create the command to send to the master, we use redis binary
|
|
* protocol to make sure correct arguments are sent. This function
|
|
* is not safe for all binary data. */
|
|
va_start(ap,conn);
|
|
while(1) {
|
|
arg = va_arg(ap, char*);
|
|
if (arg == NULL) break;
|
|
cmdargs = sdscatprintf(cmdargs,"$%zu\r\n%s\r\n",strlen(arg),arg);
|
|
argslen++;
|
|
}
|
|
|
|
cmd = sdscatprintf(cmd,"*%zu\r\n",argslen);
|
|
cmd = sdscatsds(cmd,cmdargs);
|
|
sdsfree(cmdargs);
|
|
|
|
va_end(ap);
|
|
char* err = sendCommandRaw(conn, cmd);
|
|
sdsfree(cmd);
|
|
if(err)
|
|
return err;
|
|
return NULL;
|
|
}
|
|
|
|
/* Compose a multi-bulk command and send it to the connection.
|
|
* Used to send AUTH and REPLCONF commands to the master before starting the
|
|
* replication.
|
|
*
|
|
* argv_lens is optional, when NULL, strlen is used.
|
|
*
|
|
* The command returns an sds string representing the result of the
|
|
* operation. On error the first byte is a "-".
|
|
*/
|
|
char *sendCommandArgv(connection *conn, int argc, char **argv, size_t *argv_lens) {
|
|
sds cmd = sdsempty();
|
|
char *arg;
|
|
int i;
|
|
|
|
/* Create the command to send to the master. */
|
|
cmd = sdscatfmt(cmd,"*%i\r\n",argc);
|
|
for (i=0; i<argc; i++) {
|
|
int len;
|
|
arg = argv[i];
|
|
len = argv_lens ? argv_lens[i] : strlen(arg);
|
|
cmd = sdscatfmt(cmd,"$%i\r\n",len);
|
|
cmd = sdscatlen(cmd,arg,len);
|
|
cmd = sdscatlen(cmd,"\r\n",2);
|
|
}
|
|
char* err = sendCommandRaw(conn, cmd);
|
|
sdsfree(cmd);
|
|
if (err)
|
|
return err;
|
|
return NULL;
|
|
}
|
|
|
|
/* Try a partial resynchronization with the master if we are about to reconnect.
|
|
* If there is no cached master structure, at least try to issue a
|
|
* "PSYNC ? -1" command in order to trigger a full resync using the PSYNC
|
|
* command in order to obtain the master replid and the master replication
|
|
* global offset.
|
|
*
|
|
* This function is designed to be called from syncWithMaster(), so the
|
|
* following assumptions are made:
|
|
*
|
|
* 1) We pass the function an already connected socket "fd".
|
|
* 2) This function does not close the file descriptor "fd". However in case
|
|
* of successful partial resynchronization, the function will reuse
|
|
* 'fd' as file descriptor of the server.master client structure.
|
|
*
|
|
* The function is split in two halves: if read_reply is 0, the function
|
|
* writes the PSYNC command on the socket, and a new function call is
|
|
* needed, with read_reply set to 1, in order to read the reply of the
|
|
* command. This is useful in order to support non blocking operations, so
|
|
* that we write, return into the event loop, and read when there are data.
|
|
*
|
|
* When read_reply is 0 the function returns PSYNC_WRITE_ERR if there
|
|
* was a write error, or PSYNC_WAIT_REPLY to signal we need another call
|
|
* with read_reply set to 1. However even when read_reply is set to 1
|
|
* the function may return PSYNC_WAIT_REPLY again to signal there were
|
|
* insufficient data to read to complete its work. We should re-enter
|
|
* into the event loop and wait in such a case.
|
|
*
|
|
* The function returns:
|
|
*
|
|
* PSYNC_CONTINUE: If the PSYNC command succeeded and we can continue.
|
|
* PSYNC_FULLRESYNC: If PSYNC is supported but a full resync is needed.
|
|
* In this case the master replid and global replication
|
|
* offset is saved.
|
|
* PSYNC_NOT_SUPPORTED: If the server does not understand PSYNC at all and
|
|
* the caller should fall back to SYNC.
|
|
* PSYNC_WRITE_ERROR: There was an error writing the command to the socket.
|
|
* PSYNC_WAIT_REPLY: Call again the function with read_reply set to 1.
|
|
* PSYNC_TRY_LATER: Master is currently in a transient error condition.
|
|
*
|
|
* Notable side effects:
|
|
*
|
|
* 1) As a side effect of the function call the function removes the readable
|
|
* event handler from "fd", unless the return value is PSYNC_WAIT_REPLY.
|
|
* 2) server.master_initial_offset is set to the right value according
|
|
* to the master reply. This will be used to populate the 'server.master'
|
|
* structure replication offset.
|
|
*/
|
|
|
|
#define PSYNC_WRITE_ERROR 0
|
|
#define PSYNC_WAIT_REPLY 1
|
|
#define PSYNC_CONTINUE 2
|
|
#define PSYNC_FULLRESYNC 3
|
|
#define PSYNC_NOT_SUPPORTED 4
|
|
#define PSYNC_TRY_LATER 5
|
|
int slaveTryPartialResynchronization(connection *conn, int read_reply) {
|
|
char *psync_replid;
|
|
char psync_offset[32];
|
|
sds reply;
|
|
|
|
/* Writing half */
|
|
if (!read_reply) {
|
|
/* Initially set master_initial_offset to -1 to mark the current
|
|
* master replid and offset as not valid. Later if we'll be able to do
|
|
* a FULL resync using the PSYNC command we'll set the offset at the
|
|
* right value, so that this information will be propagated to the
|
|
* client structure representing the master into server.master. */
|
|
server.master_initial_offset = -1;
|
|
|
|
if (server.cached_master) {
|
|
psync_replid = server.cached_master->replid;
|
|
snprintf(psync_offset,sizeof(psync_offset),"%lld", server.cached_master->reploff+1);
|
|
serverLog(LL_NOTICE,"Trying a partial resynchronization (request %s:%s).", psync_replid, psync_offset);
|
|
} else {
|
|
serverLog(LL_NOTICE,"Partial resynchronization not possible (no cached master)");
|
|
psync_replid = "?";
|
|
memcpy(psync_offset,"-1",3);
|
|
}
|
|
|
|
/* Issue the PSYNC command, if this is a master with a failover in
|
|
* progress then send the failover argument to the replica to cause it
|
|
* to become a master */
|
|
if (server.failover_state == FAILOVER_IN_PROGRESS) {
|
|
reply = sendCommand(conn,"PSYNC",psync_replid,psync_offset,"FAILOVER",NULL);
|
|
} else {
|
|
reply = sendCommand(conn,"PSYNC",psync_replid,psync_offset,NULL);
|
|
}
|
|
|
|
if (reply != NULL) {
|
|
serverLog(LL_WARNING,"Unable to send PSYNC to master: %s",reply);
|
|
sdsfree(reply);
|
|
connSetReadHandler(conn, NULL);
|
|
return PSYNC_WRITE_ERROR;
|
|
}
|
|
return PSYNC_WAIT_REPLY;
|
|
}
|
|
|
|
/* Reading half */
|
|
reply = receiveSynchronousResponse(conn);
|
|
/* Master did not reply to PSYNC */
|
|
if (reply == NULL) {
|
|
connSetReadHandler(conn, NULL);
|
|
serverLog(LL_WARNING, "Master did not reply to PSYNC, will try later");
|
|
return PSYNC_TRY_LATER;
|
|
}
|
|
|
|
if (sdslen(reply) == 0) {
|
|
/* The master may send empty newlines after it receives PSYNC
|
|
* and before to reply, just to keep the connection alive. */
|
|
sdsfree(reply);
|
|
return PSYNC_WAIT_REPLY;
|
|
}
|
|
|
|
connSetReadHandler(conn, NULL);
|
|
|
|
if (!strncmp(reply,"+FULLRESYNC",11)) {
|
|
char *replid = NULL, *offset = NULL;
|
|
|
|
/* FULL RESYNC, parse the reply in order to extract the replid
|
|
* and the replication offset. */
|
|
replid = strchr(reply,' ');
|
|
if (replid) {
|
|
replid++;
|
|
offset = strchr(replid,' ');
|
|
if (offset) offset++;
|
|
}
|
|
if (!replid || !offset || (offset-replid-1) != CONFIG_RUN_ID_SIZE) {
|
|
serverLog(LL_WARNING,
|
|
"Master replied with wrong +FULLRESYNC syntax.");
|
|
/* This is an unexpected condition, actually the +FULLRESYNC
|
|
* reply means that the master supports PSYNC, but the reply
|
|
* format seems wrong. To stay safe we blank the master
|
|
* replid to make sure next PSYNCs will fail. */
|
|
memset(server.master_replid,0,CONFIG_RUN_ID_SIZE+1);
|
|
} else {
|
|
memcpy(server.master_replid, replid, offset-replid-1);
|
|
server.master_replid[CONFIG_RUN_ID_SIZE] = '\0';
|
|
server.master_initial_offset = strtoll(offset,NULL,10);
|
|
serverLog(LL_NOTICE,"Full resync from master: %s:%lld",
|
|
server.master_replid,
|
|
server.master_initial_offset);
|
|
}
|
|
sdsfree(reply);
|
|
return PSYNC_FULLRESYNC;
|
|
}
|
|
|
|
if (!strncmp(reply,"+CONTINUE",9)) {
|
|
/* Partial resync was accepted. */
|
|
serverLog(LL_NOTICE,
|
|
"Successful partial resynchronization with master.");
|
|
|
|
/* Check the new replication ID advertised by the master. If it
|
|
* changed, we need to set the new ID as primary ID, and set
|
|
* secondary ID as the old master ID up to the current offset, so
|
|
* that our sub-slaves will be able to PSYNC with us after a
|
|
* disconnection. */
|
|
char *start = reply+10;
|
|
char *end = reply+9;
|
|
while(end[0] != '\r' && end[0] != '\n' && end[0] != '\0') end++;
|
|
if (end-start == CONFIG_RUN_ID_SIZE) {
|
|
char new[CONFIG_RUN_ID_SIZE+1];
|
|
memcpy(new,start,CONFIG_RUN_ID_SIZE);
|
|
new[CONFIG_RUN_ID_SIZE] = '\0';
|
|
|
|
if (strcmp(new,server.cached_master->replid)) {
|
|
/* Master ID changed. */
|
|
serverLog(LL_NOTICE,"Master replication ID changed to %s",new);
|
|
|
|
/* Set the old ID as our ID2, up to the current offset+1. */
|
|
memcpy(server.replid2,server.cached_master->replid,
|
|
sizeof(server.replid2));
|
|
server.second_replid_offset = server.master_repl_offset+1;
|
|
|
|
/* Update the cached master ID and our own primary ID to the
|
|
* new one. */
|
|
memcpy(server.replid,new,sizeof(server.replid));
|
|
memcpy(server.cached_master->replid,new,sizeof(server.replid));
|
|
|
|
/* Disconnect all the sub-slaves: they need to be notified. */
|
|
disconnectSlaves();
|
|
}
|
|
}
|
|
|
|
/* Setup the replication to continue. */
|
|
sdsfree(reply);
|
|
replicationResurrectCachedMaster(conn);
|
|
|
|
/* If this instance was restarted and we read the metadata to
|
|
* PSYNC from the persistence file, our replication backlog could
|
|
* be still not initialized. Create it. */
|
|
if (server.repl_backlog == NULL) createReplicationBacklog();
|
|
return PSYNC_CONTINUE;
|
|
}
|
|
|
|
/* If we reach this point we received either an error (since the master does
|
|
* not understand PSYNC or because it is in a special state and cannot
|
|
* serve our request), or an unexpected reply from the master.
|
|
*
|
|
* Return PSYNC_NOT_SUPPORTED on errors we don't understand, otherwise
|
|
* return PSYNC_TRY_LATER if we believe this is a transient error. */
|
|
|
|
if (!strncmp(reply,"-NOMASTERLINK",13) ||
|
|
!strncmp(reply,"-LOADING",8))
|
|
{
|
|
serverLog(LL_NOTICE,
|
|
"Master is currently unable to PSYNC "
|
|
"but should be in the future: %s", reply);
|
|
sdsfree(reply);
|
|
return PSYNC_TRY_LATER;
|
|
}
|
|
|
|
if (strncmp(reply,"-ERR",4)) {
|
|
/* If it's not an error, log the unexpected event. */
|
|
serverLog(LL_WARNING,
|
|
"Unexpected reply to PSYNC from master: %s", reply);
|
|
} else {
|
|
serverLog(LL_NOTICE,
|
|
"Master does not support PSYNC or is in "
|
|
"error state (reply: %s)", reply);
|
|
}
|
|
sdsfree(reply);
|
|
return PSYNC_NOT_SUPPORTED;
|
|
}
|
|
|
|
/* This handler fires when the non blocking connect was able to
|
|
* establish a connection with the master. */
|
|
void syncWithMaster(connection *conn) {
|
|
char tmpfile[256], *err = NULL;
|
|
int dfd = -1, maxtries = 5;
|
|
int psync_result;
|
|
|
|
/* If this event fired after the user turned the instance into a master
|
|
* with SLAVEOF NO ONE we must just return ASAP. */
|
|
if (server.repl_state == REPL_STATE_NONE) {
|
|
connClose(conn);
|
|
return;
|
|
}
|
|
|
|
/* Check for errors in the socket: after a non blocking connect() we
|
|
* may find that the socket is in error state. */
|
|
if (connGetState(conn) != CONN_STATE_CONNECTED) {
|
|
serverLog(LL_WARNING,"Error condition on socket for SYNC: %s",
|
|
connGetLastError(conn));
|
|
goto error;
|
|
}
|
|
|
|
/* Send a PING to check the master is able to reply without errors. */
|
|
if (server.repl_state == REPL_STATE_CONNECTING) {
|
|
serverLog(LL_NOTICE,"Non blocking connect for SYNC fired the event.");
|
|
/* Delete the writable event so that the readable event remains
|
|
* registered and we can wait for the PONG reply. */
|
|
connSetReadHandler(conn, syncWithMaster);
|
|
connSetWriteHandler(conn, NULL);
|
|
server.repl_state = REPL_STATE_RECEIVE_PING_REPLY;
|
|
/* Send the PING, don't check for errors at all, we have the timeout
|
|
* that will take care about this. */
|
|
err = sendCommand(conn,"PING",NULL);
|
|
if (err) goto write_error;
|
|
return;
|
|
}
|
|
|
|
/* Receive the PONG command. */
|
|
if (server.repl_state == REPL_STATE_RECEIVE_PING_REPLY) {
|
|
err = receiveSynchronousResponse(conn);
|
|
|
|
/* The master did not reply */
|
|
if (err == NULL) goto no_response_error;
|
|
|
|
/* We accept only two replies as valid, a positive +PONG reply
|
|
* (we just check for "+") or an authentication error.
|
|
* Note that older versions of Redis replied with "operation not
|
|
* permitted" instead of using a proper error code, so we test
|
|
* both. */
|
|
if (err[0] != '+' &&
|
|
strncmp(err,"-NOAUTH",7) != 0 &&
|
|
strncmp(err,"-NOPERM",7) != 0 &&
|
|
strncmp(err,"-ERR operation not permitted",28) != 0)
|
|
{
|
|
serverLog(LL_WARNING,"Error reply to PING from master: '%s'",err);
|
|
sdsfree(err);
|
|
goto error;
|
|
} else {
|
|
serverLog(LL_NOTICE,
|
|
"Master replied to PING, replication can continue...");
|
|
}
|
|
sdsfree(err);
|
|
err = NULL;
|
|
server.repl_state = REPL_STATE_SEND_HANDSHAKE;
|
|
}
|
|
|
|
if (server.repl_state == REPL_STATE_SEND_HANDSHAKE) {
|
|
/* AUTH with the master if required. */
|
|
if (server.masterauth) {
|
|
char *args[3] = {"AUTH",NULL,NULL};
|
|
size_t lens[3] = {4,0,0};
|
|
int argc = 1;
|
|
if (server.masteruser) {
|
|
args[argc] = server.masteruser;
|
|
lens[argc] = strlen(server.masteruser);
|
|
argc++;
|
|
}
|
|
args[argc] = server.masterauth;
|
|
lens[argc] = sdslen(server.masterauth);
|
|
argc++;
|
|
err = sendCommandArgv(conn, argc, args, lens);
|
|
if (err) goto write_error;
|
|
}
|
|
|
|
/* Set the slave port, so that Master's INFO command can list the
|
|
* slave listening port correctly. */
|
|
{
|
|
int port;
|
|
if (server.slave_announce_port)
|
|
port = server.slave_announce_port;
|
|
else if (server.tls_replication && server.tls_port)
|
|
port = server.tls_port;
|
|
else
|
|
port = server.port;
|
|
sds portstr = sdsfromlonglong(port);
|
|
err = sendCommand(conn,"REPLCONF",
|
|
"listening-port",portstr, NULL);
|
|
sdsfree(portstr);
|
|
if (err) goto write_error;
|
|
}
|
|
|
|
/* Set the slave ip, so that Master's INFO command can list the
|
|
* slave IP address port correctly in case of port forwarding or NAT.
|
|
* Skip REPLCONF ip-address if there is no slave-announce-ip option set. */
|
|
if (server.slave_announce_ip) {
|
|
err = sendCommand(conn,"REPLCONF",
|
|
"ip-address",server.slave_announce_ip, NULL);
|
|
if (err) goto write_error;
|
|
}
|
|
|
|
/* Inform the master of our (slave) capabilities.
|
|
*
|
|
* EOF: supports EOF-style RDB transfer for diskless replication.
|
|
* PSYNC2: supports PSYNC v2, so understands +CONTINUE <new repl ID>.
|
|
*
|
|
* The master will ignore capabilities it does not understand. */
|
|
err = sendCommand(conn,"REPLCONF",
|
|
"capa","eof","capa","psync2",NULL);
|
|
if (err) goto write_error;
|
|
|
|
server.repl_state = REPL_STATE_RECEIVE_AUTH_REPLY;
|
|
return;
|
|
}
|
|
|
|
if (server.repl_state == REPL_STATE_RECEIVE_AUTH_REPLY && !server.masterauth)
|
|
server.repl_state = REPL_STATE_RECEIVE_PORT_REPLY;
|
|
|
|
/* Receive AUTH reply. */
|
|
if (server.repl_state == REPL_STATE_RECEIVE_AUTH_REPLY) {
|
|
err = receiveSynchronousResponse(conn);
|
|
if (err == NULL) goto no_response_error;
|
|
if (err[0] == '-') {
|
|
serverLog(LL_WARNING,"Unable to AUTH to MASTER: %s",err);
|
|
sdsfree(err);
|
|
goto error;
|
|
}
|
|
sdsfree(err);
|
|
err = NULL;
|
|
server.repl_state = REPL_STATE_RECEIVE_PORT_REPLY;
|
|
return;
|
|
}
|
|
|
|
/* Receive REPLCONF listening-port reply. */
|
|
if (server.repl_state == REPL_STATE_RECEIVE_PORT_REPLY) {
|
|
err = receiveSynchronousResponse(conn);
|
|
if (err == NULL) goto no_response_error;
|
|
/* Ignore the error if any, not all the Redis versions support
|
|
* REPLCONF listening-port. */
|
|
if (err[0] == '-') {
|
|
serverLog(LL_NOTICE,"(Non critical) Master does not understand "
|
|
"REPLCONF listening-port: %s", err);
|
|
}
|
|
sdsfree(err);
|
|
server.repl_state = REPL_STATE_RECEIVE_IP_REPLY;
|
|
return;
|
|
}
|
|
|
|
if (server.repl_state == REPL_STATE_RECEIVE_IP_REPLY && !server.slave_announce_ip)
|
|
server.repl_state = REPL_STATE_RECEIVE_CAPA_REPLY;
|
|
|
|
/* Receive REPLCONF ip-address reply. */
|
|
if (server.repl_state == REPL_STATE_RECEIVE_IP_REPLY) {
|
|
err = receiveSynchronousResponse(conn);
|
|
if (err == NULL) goto no_response_error;
|
|
/* Ignore the error if any, not all the Redis versions support
|
|
* REPLCONF ip-address. */
|
|
if (err[0] == '-') {
|
|
serverLog(LL_NOTICE,"(Non critical) Master does not understand "
|
|
"REPLCONF ip-address: %s", err);
|
|
}
|
|
sdsfree(err);
|
|
server.repl_state = REPL_STATE_RECEIVE_CAPA_REPLY;
|
|
return;
|
|
}
|
|
|
|
/* Receive CAPA reply. */
|
|
if (server.repl_state == REPL_STATE_RECEIVE_CAPA_REPLY) {
|
|
err = receiveSynchronousResponse(conn);
|
|
if (err == NULL) goto no_response_error;
|
|
/* Ignore the error if any, not all the Redis versions support
|
|
* REPLCONF capa. */
|
|
if (err[0] == '-') {
|
|
serverLog(LL_NOTICE,"(Non critical) Master does not understand "
|
|
"REPLCONF capa: %s", err);
|
|
}
|
|
sdsfree(err);
|
|
err = NULL;
|
|
server.repl_state = REPL_STATE_SEND_PSYNC;
|
|
}
|
|
|
|
/* Try a partial resynchronization. If we don't have a cached master
|
|
* slaveTryPartialResynchronization() will at least try to use PSYNC
|
|
* to start a full resynchronization so that we get the master replid
|
|
* and the global offset, to try a partial resync at the next
|
|
* reconnection attempt. */
|
|
if (server.repl_state == REPL_STATE_SEND_PSYNC) {
|
|
if (slaveTryPartialResynchronization(conn,0) == PSYNC_WRITE_ERROR) {
|
|
err = sdsnew("Write error sending the PSYNC command.");
|
|
abortFailover("Write error to failover target");
|
|
goto write_error;
|
|
}
|
|
server.repl_state = REPL_STATE_RECEIVE_PSYNC_REPLY;
|
|
return;
|
|
}
|
|
|
|
/* If reached this point, we should be in REPL_STATE_RECEIVE_PSYNC_REPLY. */
|
|
if (server.repl_state != REPL_STATE_RECEIVE_PSYNC_REPLY) {
|
|
serverLog(LL_WARNING,"syncWithMaster(): state machine error, "
|
|
"state should be RECEIVE_PSYNC but is %d",
|
|
server.repl_state);
|
|
goto error;
|
|
}
|
|
|
|
psync_result = slaveTryPartialResynchronization(conn,1);
|
|
if (psync_result == PSYNC_WAIT_REPLY) return; /* Try again later... */
|
|
|
|
/* Check the status of the planned failover. We expect PSYNC_CONTINUE,
|
|
* but there is nothing technically wrong with a full resync which
|
|
* could happen in edge cases. */
|
|
if (server.failover_state == FAILOVER_IN_PROGRESS) {
|
|
if (psync_result == PSYNC_CONTINUE || psync_result == PSYNC_FULLRESYNC) {
|
|
clearFailoverState();
|
|
} else {
|
|
abortFailover("Failover target rejected psync request");
|
|
return;
|
|
}
|
|
}
|
|
|
|
/* If the master is in an transient error, we should try to PSYNC
|
|
* from scratch later, so go to the error path. This happens when
|
|
* the server is loading the dataset or is not connected with its
|
|
* master and so forth. */
|
|
if (psync_result == PSYNC_TRY_LATER) goto error;
|
|
|
|
/* Note: if PSYNC does not return WAIT_REPLY, it will take care of
|
|
* uninstalling the read handler from the file descriptor. */
|
|
|
|
if (psync_result == PSYNC_CONTINUE) {
|
|
serverLog(LL_NOTICE, "MASTER <-> REPLICA sync: Master accepted a Partial Resynchronization.");
|
|
if (server.supervised_mode == SUPERVISED_SYSTEMD) {
|
|
redisCommunicateSystemd("STATUS=MASTER <-> REPLICA sync: Partial Resynchronization accepted. Ready to accept connections in read-write mode.\n");
|
|
}
|
|
return;
|
|
}
|
|
|
|
/* Fall back to SYNC if needed. Otherwise psync_result == PSYNC_FULLRESYNC
|
|
* and the server.master_replid and master_initial_offset are
|
|
* already populated. */
|
|
if (psync_result == PSYNC_NOT_SUPPORTED) {
|
|
serverLog(LL_NOTICE,"Retrying with SYNC...");
|
|
if (connSyncWrite(conn,"SYNC\r\n",6,server.repl_syncio_timeout*1000) == -1) {
|
|
serverLog(LL_WARNING,"I/O error writing to MASTER: %s",
|
|
connGetLastError(conn));
|
|
goto error;
|
|
}
|
|
}
|
|
|
|
/* Prepare a suitable temp file for bulk transfer */
|
|
if (!useDisklessLoad()) {
|
|
while(maxtries--) {
|
|
snprintf(tmpfile,256,
|
|
"temp-%d.%ld.rdb",(int)server.unixtime,(long int)getpid());
|
|
dfd = open(tmpfile,O_CREAT|O_WRONLY|O_EXCL,0644);
|
|
if (dfd != -1) break;
|
|
sleep(1);
|
|
}
|
|
if (dfd == -1) {
|
|
serverLog(LL_WARNING,"Opening the temp file needed for MASTER <-> REPLICA synchronization: %s",strerror(errno));
|
|
goto error;
|
|
}
|
|
server.repl_transfer_tmpfile = zstrdup(tmpfile);
|
|
server.repl_transfer_fd = dfd;
|
|
}
|
|
|
|
/* Setup the non blocking download of the bulk file. */
|
|
if (connSetReadHandler(conn, readSyncBulkPayload)
|
|
== C_ERR)
|
|
{
|
|
char conninfo[CONN_INFO_LEN];
|
|
serverLog(LL_WARNING,
|
|
"Can't create readable event for SYNC: %s (%s)",
|
|
strerror(errno), connGetInfo(conn, conninfo, sizeof(conninfo)));
|
|
goto error;
|
|
}
|
|
|
|
server.repl_state = REPL_STATE_TRANSFER;
|
|
server.repl_transfer_size = -1;
|
|
server.repl_transfer_read = 0;
|
|
server.repl_transfer_last_fsync_off = 0;
|
|
server.repl_transfer_lastio = server.unixtime;
|
|
return;
|
|
|
|
no_response_error: /* Handle receiveSynchronousResponse() error when master has no reply */
|
|
serverLog(LL_WARNING, "Master did not respond to command during SYNC handshake");
|
|
/* Fall through to regular error handling */
|
|
|
|
error:
|
|
if (dfd != -1) close(dfd);
|
|
connClose(conn);
|
|
server.repl_transfer_s = NULL;
|
|
if (server.repl_transfer_fd != -1)
|
|
close(server.repl_transfer_fd);
|
|
if (server.repl_transfer_tmpfile)
|
|
zfree(server.repl_transfer_tmpfile);
|
|
server.repl_transfer_tmpfile = NULL;
|
|
server.repl_transfer_fd = -1;
|
|
server.repl_state = REPL_STATE_CONNECT;
|
|
return;
|
|
|
|
write_error: /* Handle sendCommand() errors. */
|
|
serverLog(LL_WARNING,"Sending command to master in replication handshake: %s", err);
|
|
sdsfree(err);
|
|
goto error;
|
|
}
|
|
|
|
int connectWithMaster(void) {
|
|
server.repl_transfer_s = connCreate(connTypeOfReplication());
|
|
if (connConnect(server.repl_transfer_s, server.masterhost, server.masterport,
|
|
server.bind_source_addr, syncWithMaster) == C_ERR) {
|
|
serverLog(LL_WARNING,"Unable to connect to MASTER: %s",
|
|
connGetLastError(server.repl_transfer_s));
|
|
connClose(server.repl_transfer_s);
|
|
server.repl_transfer_s = NULL;
|
|
return C_ERR;
|
|
}
|
|
|
|
|
|
server.repl_transfer_lastio = server.unixtime;
|
|
server.repl_state = REPL_STATE_CONNECTING;
|
|
serverLog(LL_NOTICE,"MASTER <-> REPLICA sync started");
|
|
return C_OK;
|
|
}
|
|
|
|
/* This function can be called when a non blocking connection is currently
|
|
* in progress to undo it.
|
|
* Never call this function directly, use cancelReplicationHandshake() instead.
|
|
*/
|
|
void undoConnectWithMaster(void) {
|
|
connClose(server.repl_transfer_s);
|
|
server.repl_transfer_s = NULL;
|
|
}
|
|
|
|
/* Abort the async download of the bulk dataset while SYNC-ing with master.
|
|
* Never call this function directly, use cancelReplicationHandshake() instead.
|
|
*/
|
|
void replicationAbortSyncTransfer(void) {
|
|
serverAssert(server.repl_state == REPL_STATE_TRANSFER);
|
|
undoConnectWithMaster();
|
|
if (server.repl_transfer_fd!=-1) {
|
|
close(server.repl_transfer_fd);
|
|
bg_unlink(server.repl_transfer_tmpfile);
|
|
zfree(server.repl_transfer_tmpfile);
|
|
server.repl_transfer_tmpfile = NULL;
|
|
server.repl_transfer_fd = -1;
|
|
}
|
|
}
|
|
|
|
/* This function aborts a non blocking replication attempt if there is one
|
|
* in progress, by canceling the non-blocking connect attempt or
|
|
* the initial bulk transfer.
|
|
*
|
|
* If there was a replication handshake in progress 1 is returned and
|
|
* the replication state (server.repl_state) set to REPL_STATE_CONNECT.
|
|
*
|
|
* Otherwise zero is returned and no operation is performed at all. */
|
|
int cancelReplicationHandshake(int reconnect) {
|
|
if (server.repl_state == REPL_STATE_TRANSFER) {
|
|
replicationAbortSyncTransfer();
|
|
server.repl_state = REPL_STATE_CONNECT;
|
|
} else if (server.repl_state == REPL_STATE_CONNECTING ||
|
|
slaveIsInHandshakeState())
|
|
{
|
|
undoConnectWithMaster();
|
|
server.repl_state = REPL_STATE_CONNECT;
|
|
} else {
|
|
return 0;
|
|
}
|
|
|
|
if (!reconnect)
|
|
return 1;
|
|
|
|
/* try to re-connect without waiting for replicationCron, this is needed
|
|
* for the "diskless loading short read" test. */
|
|
serverLog(LL_NOTICE,"Reconnecting to MASTER %s:%d after failure",
|
|
server.masterhost, server.masterport);
|
|
connectWithMaster();
|
|
|
|
return 1;
|
|
}
|
|
|
|
/* Set replication to the specified master address and port. */
|
|
void replicationSetMaster(char *ip, int port) {
|
|
int was_master = server.masterhost == NULL;
|
|
|
|
sdsfree(server.masterhost);
|
|
server.masterhost = NULL;
|
|
if (server.master) {
|
|
freeClient(server.master);
|
|
}
|
|
disconnectAllBlockedClients(); /* Clients blocked in master, now slave. */
|
|
|
|
/* Setting masterhost only after the call to freeClient since it calls
|
|
* replicationHandleMasterDisconnection which can trigger a re-connect
|
|
* directly from within that call. */
|
|
server.masterhost = sdsnew(ip);
|
|
server.masterport = port;
|
|
|
|
/* Update oom_score_adj */
|
|
setOOMScoreAdj(-1);
|
|
|
|
/* Here we don't disconnect with replicas, since they may hopefully be able
|
|
* to partially resync with us. We will disconnect with replicas and force
|
|
* them to resync with us when changing replid on partially resync with new
|
|
* master, or finishing transferring RDB and preparing loading DB on full
|
|
* sync with new master. */
|
|
|
|
cancelReplicationHandshake(0);
|
|
/* Before destroying our master state, create a cached master using
|
|
* our own parameters, to later PSYNC with the new master. */
|
|
if (was_master) {
|
|
replicationDiscardCachedMaster();
|
|
replicationCacheMasterUsingMyself();
|
|
}
|
|
|
|
/* Fire the role change modules event. */
|
|
moduleFireServerEvent(VALKEYMODULE_EVENT_REPLICATION_ROLE_CHANGED,
|
|
VALKEYMODULE_EVENT_REPLROLECHANGED_NOW_REPLICA,
|
|
NULL);
|
|
|
|
/* Fire the master link modules event. */
|
|
if (server.repl_state == REPL_STATE_CONNECTED)
|
|
moduleFireServerEvent(VALKEYMODULE_EVENT_PRIMARY_LINK_CHANGE,
|
|
VALKEYMODULE_SUBEVENT_PRIMARY_LINK_DOWN,
|
|
NULL);
|
|
|
|
server.repl_state = REPL_STATE_CONNECT;
|
|
serverLog(LL_NOTICE,"Connecting to MASTER %s:%d",
|
|
server.masterhost, server.masterport);
|
|
connectWithMaster();
|
|
}
|
|
|
|
/* Cancel replication, setting the instance as a master itself. */
|
|
void replicationUnsetMaster(void) {
|
|
if (server.masterhost == NULL) return; /* Nothing to do. */
|
|
|
|
/* Fire the master link modules event. */
|
|
if (server.repl_state == REPL_STATE_CONNECTED)
|
|
moduleFireServerEvent(VALKEYMODULE_EVENT_PRIMARY_LINK_CHANGE,
|
|
VALKEYMODULE_SUBEVENT_PRIMARY_LINK_DOWN,
|
|
NULL);
|
|
|
|
/* Clear masterhost first, since the freeClient calls
|
|
* replicationHandleMasterDisconnection which can attempt to re-connect. */
|
|
sdsfree(server.masterhost);
|
|
server.masterhost = NULL;
|
|
if (server.master) freeClient(server.master);
|
|
replicationDiscardCachedMaster();
|
|
cancelReplicationHandshake(0);
|
|
/* When a slave is turned into a master, the current replication ID
|
|
* (that was inherited from the master at synchronization time) is
|
|
* used as secondary ID up to the current offset, and a new replication
|
|
* ID is created to continue with a new replication history. */
|
|
shiftReplicationId();
|
|
/* Disconnecting all the slaves is required: we need to inform slaves
|
|
* of the replication ID change (see shiftReplicationId() call). However
|
|
* the slaves will be able to partially resync with us, so it will be
|
|
* a very fast reconnection. */
|
|
disconnectSlaves();
|
|
server.repl_state = REPL_STATE_NONE;
|
|
|
|
/* We need to make sure the new master will start the replication stream
|
|
* with a SELECT statement. This is forced after a full resync, but
|
|
* with PSYNC version 2, there is no need for full resync after a
|
|
* master switch. */
|
|
server.slaveseldb = -1;
|
|
|
|
/* Update oom_score_adj */
|
|
setOOMScoreAdj(-1);
|
|
|
|
/* Once we turn from slave to master, we consider the starting time without
|
|
* slaves (that is used to count the replication backlog time to live) as
|
|
* starting from now. Otherwise the backlog will be freed after a
|
|
* failover if slaves do not connect immediately. */
|
|
server.repl_no_slaves_since = server.unixtime;
|
|
|
|
/* Reset down time so it'll be ready for when we turn into replica again. */
|
|
server.repl_down_since = 0;
|
|
|
|
/* Fire the role change modules event. */
|
|
moduleFireServerEvent(VALKEYMODULE_EVENT_REPLICATION_ROLE_CHANGED,
|
|
VALKEYMODULE_EVENT_REPLROLECHANGED_NOW_PRIMARY,
|
|
NULL);
|
|
|
|
/* Restart the AOF subsystem in case we shut it down during a sync when
|
|
* we were still a slave. */
|
|
if (server.aof_enabled && server.aof_state == AOF_OFF) restartAOFAfterSYNC();
|
|
}
|
|
|
|
/* This function is called when the slave lose the connection with the
|
|
* master into an unexpected way. */
|
|
void replicationHandleMasterDisconnection(void) {
|
|
/* Fire the master link modules event. */
|
|
if (server.repl_state == REPL_STATE_CONNECTED)
|
|
moduleFireServerEvent(VALKEYMODULE_EVENT_PRIMARY_LINK_CHANGE,
|
|
VALKEYMODULE_SUBEVENT_PRIMARY_LINK_DOWN,
|
|
NULL);
|
|
|
|
server.master = NULL;
|
|
server.repl_state = REPL_STATE_CONNECT;
|
|
server.repl_down_since = server.unixtime;
|
|
/* We lost connection with our master, don't disconnect slaves yet,
|
|
* maybe we'll be able to PSYNC with our master later. We'll disconnect
|
|
* the slaves only if we'll have to do a full resync with our master. */
|
|
|
|
/* Try to re-connect immediately rather than wait for replicationCron
|
|
* waiting 1 second may risk backlog being recycled. */
|
|
if (server.masterhost) {
|
|
serverLog(LL_NOTICE,"Reconnecting to MASTER %s:%d",
|
|
server.masterhost, server.masterport);
|
|
connectWithMaster();
|
|
}
|
|
}
|
|
|
|
void replicaofCommand(client *c) {
|
|
/* SLAVEOF is not allowed in cluster mode as replication is automatically
|
|
* configured using the current address of the master node. */
|
|
if (server.cluster_enabled) {
|
|
addReplyError(c,"REPLICAOF not allowed in cluster mode.");
|
|
return;
|
|
}
|
|
|
|
if (server.failover_state != NO_FAILOVER) {
|
|
addReplyError(c,"REPLICAOF not allowed while failing over.");
|
|
return;
|
|
}
|
|
|
|
/* The special host/port combination "NO" "ONE" turns the instance
|
|
* into a master. Otherwise the new master address is set. */
|
|
if (!strcasecmp(c->argv[1]->ptr,"no") &&
|
|
!strcasecmp(c->argv[2]->ptr,"one")) {
|
|
if (server.masterhost) {
|
|
replicationUnsetMaster();
|
|
sds client = catClientInfoString(sdsempty(),c);
|
|
serverLog(LL_NOTICE,"MASTER MODE enabled (user request from '%s')",
|
|
client);
|
|
sdsfree(client);
|
|
}
|
|
} else {
|
|
long port;
|
|
|
|
if (c->flags & CLIENT_SLAVE)
|
|
{
|
|
/* If a client is already a replica they cannot run this command,
|
|
* because it involves flushing all replicas (including this
|
|
* client) */
|
|
addReplyError(c, "Command is not valid when client is a replica.");
|
|
return;
|
|
}
|
|
|
|
if (getRangeLongFromObjectOrReply(c, c->argv[2], 0, 65535, &port,
|
|
"Invalid master port") != C_OK)
|
|
return;
|
|
|
|
/* Check if we are already attached to the specified master */
|
|
if (server.masterhost && !strcasecmp(server.masterhost,c->argv[1]->ptr)
|
|
&& server.masterport == port) {
|
|
serverLog(LL_NOTICE,"REPLICAOF would result into synchronization "
|
|
"with the master we are already connected "
|
|
"with. No operation performed.");
|
|
addReplySds(c,sdsnew("+OK Already connected to specified "
|
|
"master\r\n"));
|
|
return;
|
|
}
|
|
/* There was no previous master or the user specified a different one,
|
|
* we can continue. */
|
|
replicationSetMaster(c->argv[1]->ptr, port);
|
|
sds client = catClientInfoString(sdsempty(),c);
|
|
serverLog(LL_NOTICE,"REPLICAOF %s:%d enabled (user request from '%s')",
|
|
server.masterhost, server.masterport, client);
|
|
sdsfree(client);
|
|
}
|
|
addReply(c,shared.ok);
|
|
}
|
|
|
|
/* ROLE command: provide information about the role of the instance
|
|
* (master or slave) and additional information related to replication
|
|
* in an easy to process format. */
|
|
void roleCommand(client *c) {
|
|
if (server.sentinel_mode) {
|
|
sentinelRoleCommand(c);
|
|
return;
|
|
}
|
|
|
|
if (server.masterhost == NULL) {
|
|
listIter li;
|
|
listNode *ln;
|
|
void *mbcount;
|
|
int slaves = 0;
|
|
|
|
addReplyArrayLen(c,3);
|
|
addReplyBulkCBuffer(c,"master",6);
|
|
addReplyLongLong(c,server.master_repl_offset);
|
|
mbcount = addReplyDeferredLen(c);
|
|
listRewind(server.slaves,&li);
|
|
while((ln = listNext(&li))) {
|
|
client *slave = ln->value;
|
|
char ip[NET_IP_STR_LEN], *slaveaddr = slave->slave_addr;
|
|
|
|
if (!slaveaddr) {
|
|
if (connAddrPeerName(slave->conn,ip,sizeof(ip),NULL) == -1)
|
|
continue;
|
|
slaveaddr = ip;
|
|
}
|
|
if (slave->replstate != SLAVE_STATE_ONLINE) continue;
|
|
addReplyArrayLen(c,3);
|
|
addReplyBulkCString(c,slaveaddr);
|
|
addReplyBulkLongLong(c,slave->slave_listening_port);
|
|
addReplyBulkLongLong(c,slave->repl_ack_off);
|
|
slaves++;
|
|
}
|
|
setDeferredArrayLen(c,mbcount,slaves);
|
|
} else {
|
|
char *slavestate = NULL;
|
|
|
|
addReplyArrayLen(c,5);
|
|
addReplyBulkCBuffer(c,"slave",5);
|
|
addReplyBulkCString(c,server.masterhost);
|
|
addReplyLongLong(c,server.masterport);
|
|
if (slaveIsInHandshakeState()) {
|
|
slavestate = "handshake";
|
|
} else {
|
|
switch(server.repl_state) {
|
|
case REPL_STATE_NONE: slavestate = "none"; break;
|
|
case REPL_STATE_CONNECT: slavestate = "connect"; break;
|
|
case REPL_STATE_CONNECTING: slavestate = "connecting"; break;
|
|
case REPL_STATE_TRANSFER: slavestate = "sync"; break;
|
|
case REPL_STATE_CONNECTED: slavestate = "connected"; break;
|
|
default: slavestate = "unknown"; break;
|
|
}
|
|
}
|
|
addReplyBulkCString(c,slavestate);
|
|
addReplyLongLong(c,server.master ? server.master->reploff : -1);
|
|
}
|
|
}
|
|
|
|
/* Send a REPLCONF ACK command to the master to inform it about the current
|
|
* processed offset. If we are not connected with a master, the command has
|
|
* no effects. */
|
|
void replicationSendAck(void) {
|
|
client *c = server.master;
|
|
|
|
if (c != NULL) {
|
|
int send_fack = server.fsynced_reploff != -1;
|
|
c->flags |= CLIENT_MASTER_FORCE_REPLY;
|
|
addReplyArrayLen(c,send_fack ? 5 : 3);
|
|
addReplyBulkCString(c,"REPLCONF");
|
|
addReplyBulkCString(c,"ACK");
|
|
addReplyBulkLongLong(c,c->reploff);
|
|
if (send_fack) {
|
|
addReplyBulkCString(c,"FACK");
|
|
addReplyBulkLongLong(c,server.fsynced_reploff);
|
|
}
|
|
c->flags &= ~CLIENT_MASTER_FORCE_REPLY;
|
|
}
|
|
}
|
|
|
|
/* ---------------------- MASTER CACHING FOR PSYNC -------------------------- */
|
|
|
|
/* In order to implement partial synchronization we need to be able to cache
|
|
* our master's client structure after a transient disconnection.
|
|
* It is cached into server.cached_master and flushed away using the following
|
|
* functions. */
|
|
|
|
/* This function is called by freeClient() in order to cache the master
|
|
* client structure instead of destroying it. freeClient() will return
|
|
* ASAP after this function returns, so every action needed to avoid problems
|
|
* with a client that is really "suspended" has to be done by this function.
|
|
*
|
|
* The other functions that will deal with the cached master are:
|
|
*
|
|
* replicationDiscardCachedMaster() that will make sure to kill the client
|
|
* as for some reason we don't want to use it in the future.
|
|
*
|
|
* replicationResurrectCachedMaster() that is used after a successful PSYNC
|
|
* handshake in order to reactivate the cached master.
|
|
*/
|
|
void replicationCacheMaster(client *c) {
|
|
serverAssert(server.master != NULL && server.cached_master == NULL);
|
|
serverLog(LL_NOTICE,"Caching the disconnected master state.");
|
|
|
|
/* Unlink the client from the server structures. */
|
|
unlinkClient(c);
|
|
|
|
/* Reset the master client so that's ready to accept new commands:
|
|
* we want to discard the non processed query buffers and non processed
|
|
* offsets, including pending transactions, already populated arguments,
|
|
* pending outputs to the master. */
|
|
sdsclear(server.master->querybuf);
|
|
server.master->qb_pos = 0;
|
|
server.master->repl_applied = 0;
|
|
server.master->read_reploff = server.master->reploff;
|
|
if (c->flags & CLIENT_MULTI) discardTransaction(c);
|
|
listEmpty(c->reply);
|
|
c->sentlen = 0;
|
|
c->reply_bytes = 0;
|
|
c->bufpos = 0;
|
|
resetClient(c);
|
|
|
|
/* Save the master. Server.master will be set to null later by
|
|
* replicationHandleMasterDisconnection(). */
|
|
server.cached_master = server.master;
|
|
|
|
/* Invalidate the Peer ID cache. */
|
|
if (c->peerid) {
|
|
sdsfree(c->peerid);
|
|
c->peerid = NULL;
|
|
}
|
|
/* Invalidate the Sock Name cache. */
|
|
if (c->sockname) {
|
|
sdsfree(c->sockname);
|
|
c->sockname = NULL;
|
|
}
|
|
|
|
/* Caching the master happens instead of the actual freeClient() call,
|
|
* so make sure to adjust the replication state. This function will
|
|
* also set server.master to NULL. */
|
|
replicationHandleMasterDisconnection();
|
|
}
|
|
|
|
/* This function is called when a master is turned into a slave, in order to
|
|
* create from scratch a cached master for the new client, that will allow
|
|
* to PSYNC with the slave that was promoted as the new master after a
|
|
* failover.
|
|
*
|
|
* Assuming this instance was previously the master instance of the new master,
|
|
* the new master will accept its replication ID, and potential also the
|
|
* current offset if no data was lost during the failover. So we use our
|
|
* current replication ID and offset in order to synthesize a cached master. */
|
|
void replicationCacheMasterUsingMyself(void) {
|
|
serverLog(LL_NOTICE,
|
|
"Before turning into a replica, using my own master parameters "
|
|
"to synthesize a cached master: I may be able to synchronize with "
|
|
"the new master with just a partial transfer.");
|
|
|
|
/* This will be used to populate the field server.master->reploff
|
|
* by replicationCreateMasterClient(). We'll later set the created
|
|
* master as server.cached_master, so the replica will use such
|
|
* offset for PSYNC. */
|
|
server.master_initial_offset = server.master_repl_offset;
|
|
|
|
/* The master client we create can be set to any DBID, because
|
|
* the new master will start its replication stream with SELECT. */
|
|
replicationCreateMasterClient(NULL,-1);
|
|
|
|
/* Use our own ID / offset. */
|
|
memcpy(server.master->replid, server.replid, sizeof(server.replid));
|
|
|
|
/* Set as cached master. */
|
|
unlinkClient(server.master);
|
|
server.cached_master = server.master;
|
|
server.master = NULL;
|
|
}
|
|
|
|
/* Free a cached master, called when there are no longer the conditions for
|
|
* a partial resync on reconnection. */
|
|
void replicationDiscardCachedMaster(void) {
|
|
if (server.cached_master == NULL) return;
|
|
|
|
serverLog(LL_NOTICE,"Discarding previously cached master state.");
|
|
server.cached_master->flags &= ~CLIENT_MASTER;
|
|
freeClient(server.cached_master);
|
|
server.cached_master = NULL;
|
|
}
|
|
|
|
/* Turn the cached master into the current master, using the file descriptor
|
|
* passed as argument as the socket for the new master.
|
|
*
|
|
* This function is called when successfully setup a partial resynchronization
|
|
* so the stream of data that we'll receive will start from where this
|
|
* master left. */
|
|
void replicationResurrectCachedMaster(connection *conn) {
|
|
server.master = server.cached_master;
|
|
server.cached_master = NULL;
|
|
server.master->conn = conn;
|
|
connSetPrivateData(server.master->conn, server.master);
|
|
server.master->flags &= ~(CLIENT_CLOSE_AFTER_REPLY|CLIENT_CLOSE_ASAP);
|
|
server.master->authenticated = 1;
|
|
server.master->lastinteraction = server.unixtime;
|
|
server.repl_state = REPL_STATE_CONNECTED;
|
|
server.repl_down_since = 0;
|
|
|
|
/* Fire the master link modules event. */
|
|
moduleFireServerEvent(VALKEYMODULE_EVENT_PRIMARY_LINK_CHANGE,
|
|
VALKEYMODULE_SUBEVENT_PRIMARY_LINK_UP,
|
|
NULL);
|
|
|
|
/* Re-add to the list of clients. */
|
|
linkClient(server.master);
|
|
if (connSetReadHandler(server.master->conn, readQueryFromClient)) {
|
|
serverLog(LL_WARNING,"Error resurrecting the cached master, impossible to add the readable handler: %s", strerror(errno));
|
|
freeClientAsync(server.master); /* Close ASAP. */
|
|
}
|
|
|
|
/* We may also need to install the write handler as well if there is
|
|
* pending data in the write buffers. */
|
|
if (clientHasPendingReplies(server.master)) {
|
|
if (connSetWriteHandler(server.master->conn, sendReplyToClient)) {
|
|
serverLog(LL_WARNING,"Error resurrecting the cached master, impossible to add the writable handler: %s", strerror(errno));
|
|
freeClientAsync(server.master); /* Close ASAP. */
|
|
}
|
|
}
|
|
}
|
|
|
|
/* ------------------------- MIN-SLAVES-TO-WRITE --------------------------- */
|
|
|
|
/* This function counts the number of slaves with lag <= min-slaves-max-lag.
|
|
* If the option is active, the server will prevent writes if there are not
|
|
* enough connected slaves with the specified lag (or less). */
|
|
void refreshGoodSlavesCount(void) {
|
|
listIter li;
|
|
listNode *ln;
|
|
int good = 0;
|
|
|
|
if (!server.repl_min_slaves_to_write ||
|
|
!server.repl_min_slaves_max_lag) return;
|
|
|
|
listRewind(server.slaves,&li);
|
|
while((ln = listNext(&li))) {
|
|
client *slave = ln->value;
|
|
time_t lag = server.unixtime - slave->repl_ack_time;
|
|
|
|
if (slave->replstate == SLAVE_STATE_ONLINE &&
|
|
lag <= server.repl_min_slaves_max_lag) good++;
|
|
}
|
|
server.repl_good_slaves_count = good;
|
|
}
|
|
|
|
/* return true if status of good replicas is OK. otherwise false */
|
|
int checkGoodReplicasStatus(void) {
|
|
return server.masterhost || /* not a primary status should be OK */
|
|
!server.repl_min_slaves_max_lag || /* Min slave max lag not configured */
|
|
!server.repl_min_slaves_to_write || /* Min slave to write not configured */
|
|
server.repl_good_slaves_count >= server.repl_min_slaves_to_write; /* check if we have enough slaves */
|
|
}
|
|
|
|
/* ----------------------- SYNCHRONOUS REPLICATION --------------------------
|
|
* Redis synchronous replication design can be summarized in points:
|
|
*
|
|
* - Redis masters have a global replication offset, used by PSYNC.
|
|
* - Master increment the offset every time new commands are sent to slaves.
|
|
* - Slaves ping back masters with the offset processed so far.
|
|
*
|
|
* So synchronous replication adds a new WAIT command in the form:
|
|
*
|
|
* WAIT <num_replicas> <milliseconds_timeout>
|
|
*
|
|
* That returns the number of replicas that processed the query when
|
|
* we finally have at least num_replicas, or when the timeout was
|
|
* reached.
|
|
*
|
|
* The command is implemented in this way:
|
|
*
|
|
* - Every time a client processes a command, we remember the replication
|
|
* offset after sending that command to the slaves.
|
|
* - When WAIT is called, we ask slaves to send an acknowledgement ASAP.
|
|
* The client is blocked at the same time (see blocked.c).
|
|
* - Once we receive enough ACKs for a given offset or when the timeout
|
|
* is reached, the WAIT command is unblocked and the reply sent to the
|
|
* client.
|
|
*/
|
|
|
|
/* This just set a flag so that we broadcast a REPLCONF GETACK command
|
|
* to all the slaves in the beforeSleep() function. Note that this way
|
|
* we "group" all the clients that want to wait for synchronous replication
|
|
* in a given event loop iteration, and send a single GETACK for them all. */
|
|
void replicationRequestAckFromSlaves(void) {
|
|
server.get_ack_from_slaves = 1;
|
|
}
|
|
|
|
/* Return the number of slaves that already acknowledged the specified
|
|
* replication offset. */
|
|
int replicationCountAcksByOffset(long long offset) {
|
|
listIter li;
|
|
listNode *ln;
|
|
int count = 0;
|
|
|
|
listRewind(server.slaves,&li);
|
|
while((ln = listNext(&li))) {
|
|
client *slave = ln->value;
|
|
|
|
if (slave->replstate != SLAVE_STATE_ONLINE) continue;
|
|
if (slave->repl_ack_off >= offset) count++;
|
|
}
|
|
return count;
|
|
}
|
|
|
|
/* Return the number of replicas that already acknowledged the specified
|
|
* replication offset being AOF fsynced. */
|
|
int replicationCountAOFAcksByOffset(long long offset) {
|
|
listIter li;
|
|
listNode *ln;
|
|
int count = 0;
|
|
|
|
listRewind(server.slaves,&li);
|
|
while((ln = listNext(&li))) {
|
|
client *slave = ln->value;
|
|
|
|
if (slave->replstate != SLAVE_STATE_ONLINE) continue;
|
|
if (slave->repl_aof_off >= offset) count++;
|
|
}
|
|
return count;
|
|
}
|
|
|
|
/* WAIT for N replicas to acknowledge the processing of our latest
|
|
* write command (and all the previous commands). */
|
|
void waitCommand(client *c) {
|
|
mstime_t timeout;
|
|
long numreplicas, ackreplicas;
|
|
long long offset = c->woff;
|
|
|
|
if (server.masterhost) {
|
|
addReplyError(c,"WAIT cannot be used with replica instances. Please also note that since Redis 4.0 if a replica is configured to be writable (which is not the default) writes to replicas are just local and are not propagated.");
|
|
return;
|
|
}
|
|
|
|
/* Argument parsing. */
|
|
if (getLongFromObjectOrReply(c,c->argv[1],&numreplicas,NULL) != C_OK)
|
|
return;
|
|
if (getTimeoutFromObjectOrReply(c,c->argv[2],&timeout,UNIT_MILLISECONDS)
|
|
!= C_OK) return;
|
|
|
|
/* First try without blocking at all. */
|
|
ackreplicas = replicationCountAcksByOffset(c->woff);
|
|
if (ackreplicas >= numreplicas || c->flags & CLIENT_DENY_BLOCKING) {
|
|
addReplyLongLong(c,ackreplicas);
|
|
return;
|
|
}
|
|
|
|
/* Otherwise block the client and put it into our list of clients
|
|
* waiting for ack from slaves. */
|
|
blockForReplication(c,timeout,offset,numreplicas);
|
|
|
|
/* Make sure that the server will send an ACK request to all the slaves
|
|
* before returning to the event loop. */
|
|
replicationRequestAckFromSlaves();
|
|
}
|
|
|
|
/* WAIT for N replicas and / or local master to acknowledge our latest
|
|
* write command got synced to the disk. */
|
|
void waitaofCommand(client *c) {
|
|
mstime_t timeout;
|
|
long numreplicas, numlocal, ackreplicas, acklocal;
|
|
|
|
/* Argument parsing. */
|
|
if (getRangeLongFromObjectOrReply(c,c->argv[1],0,1,&numlocal,NULL) != C_OK)
|
|
return;
|
|
if (getPositiveLongFromObjectOrReply(c,c->argv[2],&numreplicas,NULL) != C_OK)
|
|
return;
|
|
if (getTimeoutFromObjectOrReply(c,c->argv[3],&timeout,UNIT_MILLISECONDS) != C_OK)
|
|
return;
|
|
|
|
if (server.masterhost) {
|
|
addReplyError(c,"WAITAOF cannot be used with replica instances. Please also note that writes to replicas are just local and are not propagated.");
|
|
return;
|
|
}
|
|
if (numlocal && !server.aof_enabled) {
|
|
addReplyError(c, "WAITAOF cannot be used when numlocal is set but appendonly is disabled.");
|
|
return;
|
|
}
|
|
|
|
/* First try without blocking at all. */
|
|
ackreplicas = replicationCountAOFAcksByOffset(c->woff);
|
|
acklocal = server.fsynced_reploff >= c->woff;
|
|
if ((ackreplicas >= numreplicas && acklocal >= numlocal) || c->flags & CLIENT_DENY_BLOCKING) {
|
|
addReplyArrayLen(c,2);
|
|
addReplyLongLong(c,acklocal);
|
|
addReplyLongLong(c,ackreplicas);
|
|
return;
|
|
}
|
|
|
|
/* Otherwise block the client and put it into our list of clients
|
|
* waiting for ack from slaves. */
|
|
blockForAofFsync(c,timeout,c->woff,numlocal,numreplicas);
|
|
|
|
/* Make sure that the server will send an ACK request to all the slaves
|
|
* before returning to the event loop. */
|
|
replicationRequestAckFromSlaves();
|
|
}
|
|
|
|
/* This is called by unblockClient() to perform the blocking op type
|
|
* specific cleanup. We just remove the client from the list of clients
|
|
* waiting for replica acks. Never call it directly, call unblockClient()
|
|
* instead. */
|
|
void unblockClientWaitingReplicas(client *c) {
|
|
listNode *ln = listSearchKey(server.clients_waiting_acks,c);
|
|
serverAssert(ln != NULL);
|
|
listDelNode(server.clients_waiting_acks,ln);
|
|
updateStatsOnUnblock(c, 0, 0, 0);
|
|
}
|
|
|
|
/* Check if there are clients blocked in WAIT or WAITAOF that can be unblocked
|
|
* since we received enough ACKs from slaves. */
|
|
void processClientsWaitingReplicas(void) {
|
|
long long last_offset = 0;
|
|
long long last_aof_offset = 0;
|
|
int last_numreplicas = 0;
|
|
int last_aof_numreplicas = 0;
|
|
|
|
listIter li;
|
|
listNode *ln;
|
|
|
|
listRewind(server.clients_waiting_acks,&li);
|
|
while((ln = listNext(&li))) {
|
|
int numlocal = 0;
|
|
int numreplicas = 0;
|
|
|
|
client *c = ln->value;
|
|
int is_wait_aof = c->bstate.btype == BLOCKED_WAITAOF;
|
|
|
|
if (is_wait_aof && c->bstate.numlocal && !server.aof_enabled) {
|
|
addReplyError(c, "WAITAOF cannot be used when numlocal is set but appendonly is disabled.");
|
|
unblockClient(c, 1);
|
|
continue;
|
|
}
|
|
|
|
/* Every time we find a client that is satisfied for a given
|
|
* offset and number of replicas, we remember it so the next client
|
|
* may be unblocked without calling replicationCountAcksByOffset()
|
|
* or calling replicationCountAOFAcksByOffset()
|
|
* if the requested offset / replicas were equal or less. */
|
|
if (!is_wait_aof && last_offset && last_offset >= c->bstate.reploffset &&
|
|
last_numreplicas >= c->bstate.numreplicas)
|
|
{
|
|
numreplicas = last_numreplicas;
|
|
} else if (is_wait_aof && last_aof_offset && last_aof_offset >= c->bstate.reploffset &&
|
|
last_aof_numreplicas >= c->bstate.numreplicas)
|
|
{
|
|
numreplicas = last_aof_numreplicas;
|
|
} else {
|
|
numreplicas = is_wait_aof ?
|
|
replicationCountAOFAcksByOffset(c->bstate.reploffset) :
|
|
replicationCountAcksByOffset(c->bstate.reploffset);
|
|
|
|
/* Check if the number of replicas is satisfied. */
|
|
if (numreplicas < c->bstate.numreplicas) continue;
|
|
|
|
if (is_wait_aof) {
|
|
last_aof_offset = c->bstate.reploffset;
|
|
last_aof_numreplicas = numreplicas;
|
|
} else {
|
|
last_offset = c->bstate.reploffset;
|
|
last_numreplicas = numreplicas;
|
|
}
|
|
}
|
|
|
|
/* Check if the local constraint of WAITAOF is served */
|
|
if (is_wait_aof) {
|
|
numlocal = server.fsynced_reploff >= c->bstate.reploffset;
|
|
if (numlocal < c->bstate.numlocal) continue;
|
|
}
|
|
|
|
/* Reply before unblocking, because unblock client calls reqresAppendResponse */
|
|
if (is_wait_aof) {
|
|
/* WAITAOF has an array reply */
|
|
addReplyArrayLen(c, 2);
|
|
addReplyLongLong(c, numlocal);
|
|
addReplyLongLong(c, numreplicas);
|
|
} else {
|
|
addReplyLongLong(c, numreplicas);
|
|
}
|
|
|
|
unblockClient(c, 1);
|
|
}
|
|
}
|
|
|
|
/* Return the slave replication offset for this instance, that is
|
|
* the offset for which we already processed the master replication stream. */
|
|
long long replicationGetSlaveOffset(void) {
|
|
long long offset = 0;
|
|
|
|
if (server.masterhost != NULL) {
|
|
if (server.master) {
|
|
offset = server.master->reploff;
|
|
} else if (server.cached_master) {
|
|
offset = server.cached_master->reploff;
|
|
}
|
|
}
|
|
/* offset may be -1 when the master does not support it at all, however
|
|
* this function is designed to return an offset that can express the
|
|
* amount of data processed by the master, so we return a positive
|
|
* integer. */
|
|
if (offset < 0) offset = 0;
|
|
return offset;
|
|
}
|
|
|
|
/* --------------------------- REPLICATION CRON ---------------------------- */
|
|
|
|
/* Replication cron function, called 1 time per second. */
|
|
void replicationCron(void) {
|
|
static long long replication_cron_loops = 0;
|
|
|
|
/* Check failover status first, to see if we need to start
|
|
* handling the failover. */
|
|
updateFailoverStatus();
|
|
|
|
/* Non blocking connection timeout? */
|
|
if (server.masterhost &&
|
|
(server.repl_state == REPL_STATE_CONNECTING ||
|
|
slaveIsInHandshakeState()) &&
|
|
(time(NULL)-server.repl_transfer_lastio) > server.repl_timeout)
|
|
{
|
|
serverLog(LL_WARNING,"Timeout connecting to the MASTER...");
|
|
cancelReplicationHandshake(1);
|
|
}
|
|
|
|
/* Bulk transfer I/O timeout? */
|
|
if (server.masterhost && server.repl_state == REPL_STATE_TRANSFER &&
|
|
(time(NULL)-server.repl_transfer_lastio) > server.repl_timeout)
|
|
{
|
|
serverLog(LL_WARNING,"Timeout receiving bulk data from MASTER... If the problem persists try to set the 'repl-timeout' parameter in redis.conf to a larger value.");
|
|
cancelReplicationHandshake(1);
|
|
}
|
|
|
|
/* Timed out master when we are an already connected slave? */
|
|
if (server.masterhost && server.repl_state == REPL_STATE_CONNECTED &&
|
|
(time(NULL)-server.master->lastinteraction) > server.repl_timeout)
|
|
{
|
|
serverLog(LL_WARNING,"MASTER timeout: no data nor PING received...");
|
|
freeClient(server.master);
|
|
}
|
|
|
|
/* Check if we should connect to a MASTER */
|
|
if (server.repl_state == REPL_STATE_CONNECT) {
|
|
serverLog(LL_NOTICE,"Connecting to MASTER %s:%d",
|
|
server.masterhost, server.masterport);
|
|
connectWithMaster();
|
|
}
|
|
|
|
/* Send ACK to master from time to time.
|
|
* Note that we do not send periodic acks to masters that don't
|
|
* support PSYNC and replication offsets. */
|
|
if (server.masterhost && server.master &&
|
|
!(server.master->flags & CLIENT_PRE_PSYNC))
|
|
replicationSendAck();
|
|
|
|
/* If we have attached slaves, PING them from time to time.
|
|
* So slaves can implement an explicit timeout to masters, and will
|
|
* be able to detect a link disconnection even if the TCP connection
|
|
* will not actually go down. */
|
|
listIter li;
|
|
listNode *ln;
|
|
robj *ping_argv[1];
|
|
|
|
/* First, send PING according to ping_slave_period. */
|
|
if ((replication_cron_loops % server.repl_ping_slave_period) == 0 &&
|
|
listLength(server.slaves))
|
|
{
|
|
/* Note that we don't send the PING if the clients are paused during
|
|
* a Redis Cluster manual failover: the PING we send will otherwise
|
|
* alter the replication offsets of master and slave, and will no longer
|
|
* match the one stored into 'mf_master_offset' state. */
|
|
int manual_failover_in_progress =
|
|
((server.cluster_enabled &&
|
|
server.cluster->mf_end) ||
|
|
server.failover_end_time) &&
|
|
isPausedActionsWithUpdate(PAUSE_ACTION_REPLICA);
|
|
|
|
if (!manual_failover_in_progress) {
|
|
ping_argv[0] = shared.ping;
|
|
replicationFeedSlaves(server.slaves, -1,
|
|
ping_argv, 1);
|
|
}
|
|
}
|
|
|
|
/* Second, send a newline to all the slaves in pre-synchronization
|
|
* stage, that is, slaves waiting for the master to create the RDB file.
|
|
*
|
|
* Also send the a newline to all the chained slaves we have, if we lost
|
|
* connection from our master, to keep the slaves aware that their
|
|
* master is online. This is needed since sub-slaves only receive proxied
|
|
* data from top-level masters, so there is no explicit pinging in order
|
|
* to avoid altering the replication offsets. This special out of band
|
|
* pings (newlines) can be sent, they will have no effect in the offset.
|
|
*
|
|
* The newline will be ignored by the slave but will refresh the
|
|
* last interaction timer preventing a timeout. In this case we ignore the
|
|
* ping period and refresh the connection once per second since certain
|
|
* timeouts are set at a few seconds (example: PSYNC response). */
|
|
listRewind(server.slaves,&li);
|
|
while((ln = listNext(&li))) {
|
|
client *slave = ln->value;
|
|
|
|
int is_presync =
|
|
(slave->replstate == SLAVE_STATE_WAIT_BGSAVE_START ||
|
|
(slave->replstate == SLAVE_STATE_WAIT_BGSAVE_END &&
|
|
server.rdb_child_type != RDB_CHILD_TYPE_SOCKET));
|
|
|
|
if (is_presync) {
|
|
connWrite(slave->conn, "\n", 1);
|
|
}
|
|
}
|
|
|
|
/* Disconnect timedout slaves. */
|
|
if (listLength(server.slaves)) {
|
|
listIter li;
|
|
listNode *ln;
|
|
|
|
listRewind(server.slaves,&li);
|
|
while((ln = listNext(&li))) {
|
|
client *slave = ln->value;
|
|
|
|
if (slave->replstate == SLAVE_STATE_ONLINE) {
|
|
if (slave->flags & CLIENT_PRE_PSYNC)
|
|
continue;
|
|
if ((server.unixtime - slave->repl_ack_time) > server.repl_timeout) {
|
|
serverLog(LL_WARNING, "Disconnecting timedout replica (streaming sync): %s",
|
|
replicationGetSlaveName(slave));
|
|
freeClient(slave);
|
|
continue;
|
|
}
|
|
}
|
|
/* We consider disconnecting only diskless replicas because disk-based replicas aren't fed
|
|
* by the fork child so if a disk-based replica is stuck it doesn't prevent the fork child
|
|
* from terminating. */
|
|
if (slave->replstate == SLAVE_STATE_WAIT_BGSAVE_END && server.rdb_child_type == RDB_CHILD_TYPE_SOCKET) {
|
|
if (slave->repl_last_partial_write != 0 &&
|
|
(server.unixtime - slave->repl_last_partial_write) > server.repl_timeout)
|
|
{
|
|
serverLog(LL_WARNING, "Disconnecting timedout replica (full sync): %s",
|
|
replicationGetSlaveName(slave));
|
|
freeClient(slave);
|
|
continue;
|
|
}
|
|
}
|
|
}
|
|
}
|
|
|
|
/* If this is a master without attached slaves and there is a replication
|
|
* backlog active, in order to reclaim memory we can free it after some
|
|
* (configured) time. Note that this cannot be done for slaves: slaves
|
|
* without sub-slaves attached should still accumulate data into the
|
|
* backlog, in order to reply to PSYNC queries if they are turned into
|
|
* masters after a failover. */
|
|
if (listLength(server.slaves) == 0 && server.repl_backlog_time_limit &&
|
|
server.repl_backlog && server.masterhost == NULL)
|
|
{
|
|
time_t idle = server.unixtime - server.repl_no_slaves_since;
|
|
|
|
if (idle > server.repl_backlog_time_limit) {
|
|
/* When we free the backlog, we always use a new
|
|
* replication ID and clear the ID2. This is needed
|
|
* because when there is no backlog, the master_repl_offset
|
|
* is not updated, but we would still retain our replication
|
|
* ID, leading to the following problem:
|
|
*
|
|
* 1. We are a master instance.
|
|
* 2. Our slave is promoted to master. It's repl-id-2 will
|
|
* be the same as our repl-id.
|
|
* 3. We, yet as master, receive some updates, that will not
|
|
* increment the master_repl_offset.
|
|
* 4. Later we are turned into a slave, connect to the new
|
|
* master that will accept our PSYNC request by second
|
|
* replication ID, but there will be data inconsistency
|
|
* because we received writes. */
|
|
changeReplicationId();
|
|
clearReplicationId2();
|
|
freeReplicationBacklog();
|
|
serverLog(LL_NOTICE,
|
|
"Replication backlog freed after %d seconds "
|
|
"without connected replicas.",
|
|
(int) server.repl_backlog_time_limit);
|
|
}
|
|
}
|
|
|
|
replicationStartPendingFork();
|
|
|
|
/* Remove the RDB file used for replication if Redis is not running
|
|
* with any persistence. */
|
|
removeRDBUsedToSyncReplicas();
|
|
|
|
/* Sanity check replication buffer, the first block of replication buffer blocks
|
|
* must be referenced by someone, since it will be freed when not referenced,
|
|
* otherwise, server will OOM. also, its refcount must not be more than
|
|
* replicas number + 1(replication backlog). */
|
|
if (listLength(server.repl_buffer_blocks) > 0) {
|
|
replBufBlock *o = listNodeValue(listFirst(server.repl_buffer_blocks));
|
|
serverAssert(o->refcount > 0 &&
|
|
o->refcount <= (int)listLength(server.slaves)+1);
|
|
}
|
|
|
|
/* Refresh the number of slaves with lag <= min-slaves-max-lag. */
|
|
refreshGoodSlavesCount();
|
|
replication_cron_loops++; /* Incremented with frequency 1 HZ. */
|
|
}
|
|
|
|
int shouldStartChildReplication(int *mincapa_out, int *req_out) {
|
|
/* We should start a BGSAVE good for replication if we have slaves in
|
|
* WAIT_BGSAVE_START state.
|
|
*
|
|
* In case of diskless replication, we make sure to wait the specified
|
|
* number of seconds (according to configuration) so that other slaves
|
|
* have the time to arrive before we start streaming. */
|
|
if (!hasActiveChildProcess()) {
|
|
time_t idle, max_idle = 0;
|
|
int slaves_waiting = 0;
|
|
int mincapa;
|
|
int req;
|
|
int first = 1;
|
|
listNode *ln;
|
|
listIter li;
|
|
|
|
listRewind(server.slaves,&li);
|
|
while((ln = listNext(&li))) {
|
|
client *slave = ln->value;
|
|
if (slave->replstate == SLAVE_STATE_WAIT_BGSAVE_START) {
|
|
if (first) {
|
|
/* Get first slave's requirements */
|
|
req = slave->slave_req;
|
|
} else if (req != slave->slave_req) {
|
|
/* Skip slaves that don't match */
|
|
continue;
|
|
}
|
|
idle = server.unixtime - slave->lastinteraction;
|
|
if (idle > max_idle) max_idle = idle;
|
|
slaves_waiting++;
|
|
mincapa = first ? slave->slave_capa : (mincapa & slave->slave_capa);
|
|
first = 0;
|
|
}
|
|
}
|
|
|
|
if (slaves_waiting &&
|
|
(!server.repl_diskless_sync ||
|
|
(server.repl_diskless_sync_max_replicas > 0 &&
|
|
slaves_waiting >= server.repl_diskless_sync_max_replicas) ||
|
|
max_idle >= server.repl_diskless_sync_delay))
|
|
{
|
|
if (mincapa_out)
|
|
*mincapa_out = mincapa;
|
|
if (req_out)
|
|
*req_out = req;
|
|
return 1;
|
|
}
|
|
}
|
|
|
|
return 0;
|
|
}
|
|
|
|
void replicationStartPendingFork(void) {
|
|
int mincapa = -1;
|
|
int req = -1;
|
|
|
|
if (shouldStartChildReplication(&mincapa, &req)) {
|
|
/* Start the BGSAVE. The called function may start a
|
|
* BGSAVE with socket target or disk target depending on the
|
|
* configuration and slaves capabilities and requirements. */
|
|
startBgsaveForReplication(mincapa, req);
|
|
}
|
|
}
|
|
|
|
/* Find replica at IP:PORT from replica list */
|
|
static client *findReplica(char *host, int port) {
|
|
listIter li;
|
|
listNode *ln;
|
|
client *replica;
|
|
|
|
listRewind(server.slaves,&li);
|
|
while((ln = listNext(&li))) {
|
|
replica = ln->value;
|
|
char ip[NET_IP_STR_LEN], *replicaip = replica->slave_addr;
|
|
|
|
if (!replicaip) {
|
|
if (connAddrPeerName(replica->conn, ip, sizeof(ip), NULL) == -1)
|
|
continue;
|
|
replicaip = ip;
|
|
}
|
|
|
|
if (!strcasecmp(host, replicaip) &&
|
|
(port == replica->slave_listening_port))
|
|
return replica;
|
|
}
|
|
|
|
return NULL;
|
|
}
|
|
|
|
const char *getFailoverStateString(void) {
|
|
switch(server.failover_state) {
|
|
case NO_FAILOVER: return "no-failover";
|
|
case FAILOVER_IN_PROGRESS: return "failover-in-progress";
|
|
case FAILOVER_WAIT_FOR_SYNC: return "waiting-for-sync";
|
|
default: return "unknown";
|
|
}
|
|
}
|
|
|
|
/* Resets the internal failover configuration, this needs
|
|
* to be called after a failover either succeeds or fails
|
|
* as it includes the client unpause. */
|
|
void clearFailoverState(void) {
|
|
server.failover_end_time = 0;
|
|
server.force_failover = 0;
|
|
zfree(server.target_replica_host);
|
|
server.target_replica_host = NULL;
|
|
server.target_replica_port = 0;
|
|
server.failover_state = NO_FAILOVER;
|
|
unpauseActions(PAUSE_DURING_FAILOVER);
|
|
}
|
|
|
|
/* Abort an ongoing failover if one is going on. */
|
|
void abortFailover(const char *err) {
|
|
if (server.failover_state == NO_FAILOVER) return;
|
|
|
|
if (server.target_replica_host) {
|
|
serverLog(LL_NOTICE,"FAILOVER to %s:%d aborted: %s",
|
|
server.target_replica_host,server.target_replica_port,err);
|
|
} else {
|
|
serverLog(LL_NOTICE,"FAILOVER to any replica aborted: %s",err);
|
|
}
|
|
if (server.failover_state == FAILOVER_IN_PROGRESS) {
|
|
replicationUnsetMaster();
|
|
}
|
|
clearFailoverState();
|
|
}
|
|
|
|
/*
|
|
* FAILOVER [TO <HOST> <PORT> [FORCE]] [ABORT] [TIMEOUT <timeout>]
|
|
*
|
|
* This command will coordinate a failover between the master and one
|
|
* of its replicas. The happy path contains the following steps:
|
|
* 1) The master will initiate a client pause write, to stop replication
|
|
* traffic.
|
|
* 2) The master will periodically check if any of its replicas has
|
|
* consumed the entire replication stream through acks.
|
|
* 3) Once any replica has caught up, the master will itself become a replica.
|
|
* 4) The master will send a PSYNC FAILOVER request to the target replica, which
|
|
* if accepted will cause the replica to become the new master and start a sync.
|
|
*
|
|
* FAILOVER ABORT is the only way to abort a failover command, as replicaof
|
|
* will be disabled. This may be needed if the failover is unable to progress.
|
|
*
|
|
* The optional arguments [TO <HOST> <IP>] allows designating a specific replica
|
|
* to be failed over to.
|
|
*
|
|
* FORCE flag indicates that even if the target replica is not caught up,
|
|
* failover to it anyway. This must be specified with a timeout and a target
|
|
* HOST and IP.
|
|
*
|
|
* TIMEOUT <timeout> indicates how long should the primary wait for
|
|
* a replica to sync up before aborting. If not specified, the failover
|
|
* will attempt forever and must be manually aborted.
|
|
*/
|
|
void failoverCommand(client *c) {
|
|
if (server.cluster_enabled) {
|
|
addReplyError(c,"FAILOVER not allowed in cluster mode. "
|
|
"Use CLUSTER FAILOVER command instead.");
|
|
return;
|
|
}
|
|
|
|
/* Handle special case for abort */
|
|
if ((c->argc == 2) && !strcasecmp(c->argv[1]->ptr,"abort")) {
|
|
if (server.failover_state == NO_FAILOVER) {
|
|
addReplyError(c, "No failover in progress.");
|
|
return;
|
|
}
|
|
|
|
abortFailover("Failover manually aborted");
|
|
addReply(c,shared.ok);
|
|
return;
|
|
}
|
|
|
|
long timeout_in_ms = 0;
|
|
int force_flag = 0;
|
|
long port = 0;
|
|
char *host = NULL;
|
|
|
|
/* Parse the command for syntax and arguments. */
|
|
for (int j = 1; j < c->argc; j++) {
|
|
if (!strcasecmp(c->argv[j]->ptr,"timeout") && (j + 1 < c->argc) &&
|
|
timeout_in_ms == 0)
|
|
{
|
|
if (getLongFromObjectOrReply(c,c->argv[j + 1],
|
|
&timeout_in_ms,NULL) != C_OK) return;
|
|
if (timeout_in_ms <= 0) {
|
|
addReplyError(c,"FAILOVER timeout must be greater than 0");
|
|
return;
|
|
}
|
|
j++;
|
|
} else if (!strcasecmp(c->argv[j]->ptr,"to") && (j + 2 < c->argc) &&
|
|
!host)
|
|
{
|
|
if (getLongFromObjectOrReply(c,c->argv[j + 2],&port,NULL) != C_OK)
|
|
return;
|
|
host = c->argv[j + 1]->ptr;
|
|
j += 2;
|
|
} else if (!strcasecmp(c->argv[j]->ptr,"force") && !force_flag) {
|
|
force_flag = 1;
|
|
} else {
|
|
addReplyErrorObject(c,shared.syntaxerr);
|
|
return;
|
|
}
|
|
}
|
|
|
|
if (server.failover_state != NO_FAILOVER) {
|
|
addReplyError(c,"FAILOVER already in progress.");
|
|
return;
|
|
}
|
|
|
|
if (server.masterhost) {
|
|
addReplyError(c,"FAILOVER is not valid when server is a replica.");
|
|
return;
|
|
}
|
|
|
|
if (listLength(server.slaves) == 0) {
|
|
addReplyError(c,"FAILOVER requires connected replicas.");
|
|
return;
|
|
}
|
|
|
|
if (force_flag && (!timeout_in_ms || !host)) {
|
|
addReplyError(c,"FAILOVER with force option requires both a timeout "
|
|
"and target HOST and IP.");
|
|
return;
|
|
}
|
|
|
|
/* If a replica address was provided, validate that it is connected. */
|
|
if (host) {
|
|
client *replica = findReplica(host, port);
|
|
|
|
if (replica == NULL) {
|
|
addReplyError(c,"FAILOVER target HOST and PORT is not "
|
|
"a replica.");
|
|
return;
|
|
}
|
|
|
|
/* Check if requested replica is online */
|
|
if (replica->replstate != SLAVE_STATE_ONLINE) {
|
|
addReplyError(c,"FAILOVER target replica is not online.");
|
|
return;
|
|
}
|
|
|
|
server.target_replica_host = zstrdup(host);
|
|
server.target_replica_port = port;
|
|
serverLog(LL_NOTICE,"FAILOVER requested to %s:%ld.",host,port);
|
|
} else {
|
|
serverLog(LL_NOTICE,"FAILOVER requested to any replica.");
|
|
}
|
|
|
|
mstime_t now = commandTimeSnapshot();
|
|
if (timeout_in_ms) {
|
|
server.failover_end_time = now + timeout_in_ms;
|
|
}
|
|
|
|
server.force_failover = force_flag;
|
|
server.failover_state = FAILOVER_WAIT_FOR_SYNC;
|
|
/* Cluster failover will unpause eventually */
|
|
pauseActions(PAUSE_DURING_FAILOVER,
|
|
LLONG_MAX,
|
|
PAUSE_ACTIONS_CLIENT_WRITE_SET);
|
|
addReply(c,shared.ok);
|
|
}
|
|
|
|
/* Failover cron function, checks coordinated failover state.
|
|
*
|
|
* Implementation note: The current implementation calls replicationSetMaster()
|
|
* to start the failover request, this has some unintended side effects if the
|
|
* failover doesn't work like blocked clients will be unblocked and replicas will
|
|
* be disconnected. This could be optimized further.
|
|
*/
|
|
void updateFailoverStatus(void) {
|
|
if (server.failover_state != FAILOVER_WAIT_FOR_SYNC) return;
|
|
mstime_t now = server.mstime;
|
|
|
|
/* Check if failover operation has timed out */
|
|
if (server.failover_end_time && server.failover_end_time <= now) {
|
|
if (server.force_failover) {
|
|
serverLog(LL_NOTICE,
|
|
"FAILOVER to %s:%d time out exceeded, failing over.",
|
|
server.target_replica_host, server.target_replica_port);
|
|
server.failover_state = FAILOVER_IN_PROGRESS;
|
|
/* If timeout has expired force a failover if requested. */
|
|
replicationSetMaster(server.target_replica_host,
|
|
server.target_replica_port);
|
|
return;
|
|
} else {
|
|
/* Force was not requested, so timeout. */
|
|
abortFailover("Replica never caught up before timeout");
|
|
return;
|
|
}
|
|
}
|
|
|
|
/* Check to see if the replica has caught up so failover can start */
|
|
client *replica = NULL;
|
|
if (server.target_replica_host) {
|
|
replica = findReplica(server.target_replica_host,
|
|
server.target_replica_port);
|
|
} else {
|
|
listIter li;
|
|
listNode *ln;
|
|
|
|
listRewind(server.slaves,&li);
|
|
/* Find any replica that has matched our repl_offset */
|
|
while((ln = listNext(&li))) {
|
|
replica = ln->value;
|
|
if (replica->repl_ack_off == server.master_repl_offset) {
|
|
char ip[NET_IP_STR_LEN], *replicaaddr = replica->slave_addr;
|
|
|
|
if (!replicaaddr) {
|
|
if (connAddrPeerName(replica->conn,ip,sizeof(ip),NULL) == -1)
|
|
continue;
|
|
replicaaddr = ip;
|
|
}
|
|
|
|
/* We are now failing over to this specific node */
|
|
server.target_replica_host = zstrdup(replicaaddr);
|
|
server.target_replica_port = replica->slave_listening_port;
|
|
break;
|
|
}
|
|
}
|
|
}
|
|
|
|
/* We've found a replica that is caught up */
|
|
if (replica && (replica->repl_ack_off == server.master_repl_offset)) {
|
|
server.failover_state = FAILOVER_IN_PROGRESS;
|
|
serverLog(LL_NOTICE,
|
|
"Failover target %s:%d is synced, failing over.",
|
|
server.target_replica_host, server.target_replica_port);
|
|
/* Designated replica is caught up, failover to it. */
|
|
replicationSetMaster(server.target_replica_host,
|
|
server.target_replica_port);
|
|
}
|
|
}
|