These commands are all administrator commands. If they are operated
incorrectly, serious consequences may occur. Print the full client
info by using catClientInfoString, the info is useful when we want
to identify the source of request.
Since the origin client info is very large and might complicate the
output, we added a catClientInfoShortString function, it will only
print some basic fields, we want these fields that are useful to
identify the client. These fields are:
- id
- addr
- laddr
- connection info
- name
- user
- lib-name
- lib-ver
And also used it to replace the origin client info where it has the
same purpose. Some logging is changed from full client info to short
client info:
- CLUSTER FAILOVER
- FAILOVER / PSYNC
- REPLICAOF NO ONE
- SHUTDOWN
Signed-off-by: Binbin <binloveplay1314@qq.com>
FUNCTION RESTORE have a FLUSH option, it will delete all the existing
libraries before restoring the payload. If for some reasons, there are
a lot of libraries, we will block a while in here.
Signed-off-by: Binbin <binloveplay1314@qq.com>
The goto error label is the same as the error return, use goto
to reduce the references.
```
error:
cancelReplicationHandshake(1);
return;
```
Also this can make the log printing more continuous under the
error, that is, we print the error log first, and then print
the reconnecting log at the last (in cancelReplicationHandshake).
Signed-off-by: Binbin <binloveplay1314@qq.com>
This add the missing return when repl_state change to RECEIVE_VERSION_REPLY,
this way we won’t be blocked if the primary doesn’t reply with REPLCONF
VERSION.
In practice i guess this is no likely to block in this context, reading
small responses are are likely to be received in one packet, so this
is just a cleanup (consistent with the previous state machine
processing).
Also update the state machine diagram to mention the VERSION reply.
Signed-off-by: Binbin <binloveplay1314@qq.com>
If bgsaveerr is error, there is no need to protect the rdb channel.
The impact of this may be that when bgsave fails, we will protect
the rdb channel for 60s. It may occupy the reference of the repl
buf block, making it impossible to recycle it until we free the
client due to COB or free the client after 60s.
We kept the RDB channel open as long as the replica hadn't established
a main connection, even if the snapshot process failed. There is no
value in keeping the RDB client in this case.
Signed-off-by: Binbin <binloveplay1314@qq.com>
We originally checked the replica connection to whether to kill the
diskless child only when rdbPipeReadHandler is triggered. Actually
we can check it when the replica is disconnected, so that we don't
have to wait for rdbPipeReadHandler to be triggered and can kill
the forkless child as soon as possible.
In this way, when the child or rdbPipeReadHandler is stuck for some
reason, we can kill the child faster and release the fork resources.
Signed-off-by: Binbin <binloveplay1314@qq.com>
As @madolson pointed out, these do have proper null terminators. This
cleans them up to follow the rest of the code which copies the last byte
explicitly, which should help reduce cognitive load and make it more
resilient should code refactors occur (e.g. non-static allocation of
memory, changes to other functions).
---------
Signed-off-by: Jacob Murphy <jkmurphy@google.com>
This commit addresses issues that were likely introduced during a rebase
related to:
b0f23df165
Change dual channel replication state in main handler only
Signed-off-by: naglera <anagler123@gmail.com>
In the old code, if fstat fails, replica->repldbfd will hold the
fd and we are doing a free client. And in freeClient, we check and
close only if repl_state == REPLICA_STATE_SEND_BULK. So if fstat
fails, we will leak the fd.
We can also extend freeClient to handle REPLICA_STATE_WAIT_BGSAVE_END
as well, but here seems to be a more friendly (and safer) way.
Signed-off-by: Binbin <binloveplay1314@qq.com>
A new option for diskless replication on the replica side.
After a network failure, the replica may need to perform a full sync.
The other option for diskless full sync is `swapdb`, but it uses twice
as much memory, temporarily. In situations where this is not acceptable,
and where losing data is acceptable, the `flush-before-load` can be
useful. If the full sync fails, the old data is lost though. Therefore,
the new option is marked as "dangerous".
---------
Signed-off-by: kronwerk <ca11e5e22g@gmail.com>
Signed-off-by: kronwerk <kronwerk@users.noreply.github.com>
Co-authored-by: kronwerk <ca11e5e22g@gmail.com>
This commit hopefully improves the formatting of the codebase by setting
ColumnLimit to 0 and hence stopping clang-format from trying to put as
much stuff in one line as possible.
This change enabled us to remove most of `clang-format off` directives
and fixed a bunch of lines that looked like this:
```c
#define KEY \
VALUE /* comment */
```
Additionally, one pair of `clang-format off` / `clang-format on` had
`clang-format off` as the second comment and hence didn't enable the
formatting for the rest of the file. This commit addresses this issue as
well.
Please tell me if anything in the changes seem off. If everything is
fine, I will add this commit to `.git-blame-ignore-revs` later.
---------
Signed-off-by: Mikhail Koviazin <mikhail.koviazin@aiven.io>
Call emptyData right before rdbLoad to prevent errors in the middle
and we drop the replication stream and leaving an empty database.
The real changes is in disk-based part, the rest is just code movement.
Signed-off-by: Binbin <binloveplay1314@qq.com>
Fix timing issue in evaluating `cluster-allow-replica-migration` for replicas
There is a timing bug where the primary and replica have different
`cluster-allow-replica-migration` settings. In issue #970, we found that if
the replica receives `CLUSTER SETSLOT` before the gossip update, it remains
in the original shard. This happens because we only process the
`cluster-allow-replica-migration` flag for primaries during `CLUSTER SETSLOT`.
This commit fixes the issue by also evaluating this flag for replicas in the
`CLUSTER SETSLOT` path, ensuring correct replica migration behavior.
Closes#970
---------
Signed-off-by: Binbin <binloveplay1314@qq.com>
Co-authored-by: Ping Xie <pingxie@outlook.com>
Prior to comparing the replica buffer against the configured limit, we
need to ensure that the limit configuration is enabled. If the limit is
set to zero, it indicates that there is no limit, and we should skip the
buffer limit check.
---------
Signed-off-by: naglera <anagler123@gmail.com>
Implement data masking for user data in server logs and diagnostic output. This change prevents potential exposure of confidential information, such as PII, and enhances privacy protection. It masks all command arguments, client names, and client usernames.
Added a new hide-user-data-from-log configuration item, default yes.
---------
Signed-off-by: Amit Nagler <anagler123@gmail.com>
Our current replica can initiate a failover without restriction when
it detects that the primary node is offline. This is generally not a
problem. However, consider the following scenarios:
1. In slot migration, a primary loses its last slot and then becomes
a replica. When it is fully synchronized with the new primary, the new
primary downs.
2. In CLUSTER REPLICATE command, a replica becomes a replica of another
primary. When it is fully synchronized with the new primary, the new
primary downs.
In the above scenario, case 1 may cause the empty primary to be elected
as the new primary, resulting in primary data loss. Case 2 may cause the
non-empty replica to be elected as the new primary, resulting in data
loss and confusion.
The reason is that we have cached primary logic, which is used for psync.
In the above scenario, when clusterSetPrimary is called, myself will cache
server.primary in server.cached_primary for psync. In replicationGetReplicaOffset,
we get server.cached_primary->reploff for offset, gossip it and rank it,
which causes the replica to use the old historical offset to initiate
failover, and it get a good rank, initiates election first, and then is
elected as the new primary.
The main problem here is that when the replica has not completed full
sync, it may get the historical offset in replicationGetReplicaOffset.
The fix is to clear cached_primary in these places where full sync is
obviously needed, and let the replica use offset == 0 to participate
in the election. In this way, this unhealthy replica has a worse rank
and is not easy to be elected.
Of course, it is possible that it will be elected with offset == 0.
In the future, we may need to prohibit the replica with offset == 0
from having the right to initiate elections.
Another point worth mentioning, in above cases:
1. In the ROLE command, the replica status will be handshake, and the
offset will be -1.
2. Before this PR, in the CLUSTER SHARD command, the replica status will
be online, and the offset will be the old cached value (which is wrong).
3. After this PR, in the CLUSTER SHARD, the replica status will be loading,
and the offset will be 0.
Signed-off-by: Binbin <binloveplay1314@qq.com>
In these places we should use RDB_EOF_MARK_SIZE, but we mixed
it with CONFIG_RUN_ID_SIZE. This is not an issue since they are
all 40, just a cleanup.
Signed-off-by: Binbin <binloveplay1314@qq.com>
Currently, if the client enters a blocked state, it will be
added to the server.clients_waiting_acks list. When the client
is unblocked, that is, when unblockClient is called, we will
need to linearly traverse server.clients_waiting_acks to delete
the client, and this search is O(N).
When WAIT (or WAITAOF) is used extensively in some cases, this
O(N) search may be time-consuming. We can remember the list node
and store it in the blockingState struct and it can avoid the
linear search in unblockClientWaitingReplicas.
Signed-off-by: Binbin <binloveplay1314@qq.com>
I've tried to test a dual channel replication but forgot to add +sync
for my replication user. As a result replica entered silent cycle like
this:
```
* Connecting to PRIMARY 127.0.0.1:6379
* PRIMARY <-> REPLICA sync started
* Non blocking connect for SYNC fired the event.
* Primary replied to PING, replication can continue...
* Trying a partial resynchronization (request ...)
* PSYNC is not possible, initialize RDB channel.
* Aborting dual channel sync
```
And primary got endless cycle like this:
```
* Replica 127.0.0.1:6380 asks for synchronization
* Partial resynchronization not accepted: Replication ID mismatch (Replica asked for '...', my replication IDs are '...' and '...')
* Replica 127.0.0.1:6380 is capable of dual channel synchronization, and partial sync isn't possible. Full sync will continue with dedicated RDB channel.
```
There was no way to understand that replication user is missing +sync
acl on notice log level. With this one-line change we get a warning
message in our replica log.
---------
Signed-off-by: secwall <secwall@yandex-team.ru>
Update references of copyright being assigned to Salvatore when it was
transferred to Redis Ltd. as per
https://github.com/valkey-io/valkey/issues/544.
---------
Signed-off-by: Pieter Cailliau <pieter@redis.com>
- Fix TLS bug where connection were shutdown by primary's main process
while the child process was still writing- causing main process to be
blocked.
- TLS connection fix -file descriptors are set to blocking mode in the
main thread, followed by a blocking write. This sets the file
descriptors to non-blocking if TLS is used (see `connTLSSyncWrite()`)
(@xbasel).
- Improve the reliability of dual-channel tests. Modify the pause
mechanism to verify process status directly, rather than relying on log.
- Ensure that `server.repl_offset` and `server.replid` are updated
correctly when dual channel synchronization completes successfully.
Thist led to failures in replication tests that validate replication IDs
or compare replication offsets.
---------
Signed-off-by: naglera <anagler123@gmail.com>
Signed-off-by: naglera <58042354+naglera@users.noreply.github.com>
Signed-off-by: xbasel <103044017+xbasel@users.noreply.github.com>
Signed-off-by: Madelyn Olson <madelyneolson@gmail.com>
Signed-off-by: Binbin <binloveplay1314@qq.com>
Co-authored-by: ranshid <88133677+ranshid@users.noreply.github.com>
Co-authored-by: xbasel <103044017+xbasel@users.noreply.github.com>
Co-authored-by: Madelyn Olson <madelyneolson@gmail.com>
Co-authored-by: Binbin <binloveplay1314@qq.com>
Fixes test failure
(https://github.com/valkey-io/valkey/actions/runs/10146979329/job/28056316421?pr=837)
on 32 bit system for slot stats metric underflow on the following
condition:
```
server.cluster->slot_stats[c->slot].network_bytes_out += (len * listLength(server.replicas));
```
* Here listLength accesses `len` which is of `unsigned long` type and
multiplied with `len` (which could be negative). This is a risky
operation and behaves differently based on the architecture.
```
clusterSlotStatsAddNetworkBytesOutForReplication(-sdslen(selectcmd->ptr));
```
* `sdslen` method returns `size_t`. applying `-` operation to decrement
network bytes out is also incorrect.
This change adds assertion on `len` being negative and handles the
wrapping of overall value.
---------
Signed-off-by: Harkrishn Patro <harkrisp@amazon.com>
Adds two new metrics for per-slot statistics, network-bytes-in and
network-bytes-out. The network bytes are inclusive of replication bytes
but exclude other types of network traffic such as clusterbus traffic.
#### network-bytes-in
The metric tracks network ingress bytes under per-slot context, by
reverse calculation of `c->argv_len_sum` and `c->argc`, stored under a
newly introduced field `c->net_input_bytes_curr_cmd`.
#### network-bytes-out
The metric tracks network egress bytes under per-slot context, by
hooking onto COB buffer mutations.
#### sample response
Both metrics are reported under the `CLUSTER SLOT-STATS` command.
```
127.0.0.1:6379> cluster slot-stats slotsrange 0 0
1) 1) (integer) 0
2) 1) "key-count"
2) (integer) 0
3) "cpu-usec"
4) (integer) 0
5) "network-bytes-in"
6) (integer) 0
7) "network-bytes-out"
8) (integer) 0
```
---------
Signed-off-by: Kyle Kim <kimkyle@amazon.com>
Signed-off-by: Madelyn Olson <madelyneolson@gmail.com>
Co-authored-by: Madelyn Olson <madelyneolson@gmail.com>
Introduce several improvements to improve the stability of dual-channel
replication and fix compatibility issues.
1. Make dual-channel-replication tests more reliable: use pause instead
of forced sleep.
2. Fix race conditions when freeing RDB client.
3. Check if sync was stopped during local buffer streaming.
4. Fix $ENDOFFSET reply format to work on 32-bit machines too.
---------
Signed-off-by: naglera <anagler123@gmail.com>
Signed-off-by: Madelyn Olson <madelyneolson@gmail.com>
Co-authored-by: Madelyn Olson <madelyneolson@gmail.com>
When executing the script, the client passed in is a fake
client, and its woff is always 0.
This results in woff always being 0 when executing wait/waitaof
in the script, and the command returns a wrong number.
---------
Signed-off-by: Binbin <binloveplay1314@qq.com>
In this PR we introduce the main benefit of dual channel replication by
continuously steaming the COB (client output buffers) in parallel to the
RDB and thus keeping the primary's side COB small AND accelerating the
overall sync process. By streaming the replication data to the replica
during the full sync, we reduce
1. Memory load from the primary's node.
2. CPU load from the primary's main process. [Latest performance
tests](#data)
## Motivation
* Reduce primary memory load. We do that by moving the COB tracking to
the replica side. This also decrease the chance for COB overruns. Note
that primary's input buffer limits at the replica side are less
restricted then primary's COB as the replica plays less critical part in
the replication group. While increasing the primary’s COB may end up
with primary reaching swap and clients suffering, at replica side we’re
more at ease with it. Larger COB means better chance to sync
successfully.
* Reduce primary main process CPU load. By opening a new, dedicated
connection for the RDB transfer, child processes can have direct access
to the new connection. Due to TLS connection restrictions, this was not
possible using one main connection. We eliminate the need for the child
process to use the primary's child-proc -> main-proc pipeline, thus
freeing up the main process to process clients queries.
## Dual Channel Replication high level interface design
- Dual channel replication begins when the replica sends a `REPLCONF
CAPA DUALCHANNEL` to the primary during initial
handshake. This is used to state that the replica is capable of dual
channel sync and that this is the replica's main channel, which is not
used for snapshot transfer.
- When replica lacks sufficient data for PSYNC, the primary will send
`-FULLSYNCNEEDED` response instead
of RDB data. As a next step, the replica creates a new connection
(rdb-channel) and configures it against
the primary with the appropriate capabilities and requirements. The
replica then requests a sync
using the RDB channel.
- Prior to forking, the primary sends the replica the snapshot's end
repl-offset, and attaches the replica
to the replication backlog to keep repl data until the replica requests
psync. The replica uses the main
channel to request a PSYNC starting at the snapshot end offset.
- The primary main threads sends incremental changes via the main
channel, while the bgsave process
sends the RDB directly to the replica via the rdb-channel. As for the
replica, the incremental
changes are stored on a local buffer, while the RDB is loaded into
memory.
- Once the replica completes loading the rdb, it drops the
rdb-connection and streams the accumulated incremental
changes into memory. Repl steady state continues normally.
## New replica state machine
## Data <a name="data"></a>
## Explanation
These graphs demonstrate performance improvements during full sync
sessions using rdb-channel + streaming rdb directly from the background
process to the replica.
First graph- with at most 50 clients and light weight commands, we saw
5%-7.5% improvement in write latency during sync session.
Two graphs below- full sync was tested during heavy read commands from
the primary (such as sdiff, sunion on large sets). In that case, the
child process writes to the replica without sharing CPU with the loaded
main process. As a result, this not only improves client response time,
but may also shorten sync time by about 50%. The shorter sync time
results in less memory being used to store replication diffs (>60% in
some of the tested cases).
## Test setup
Both primary and replica in the performance tests ran on the same
machine. RDB size in all tests is 3.7gb. I generated write load using
valkey-benchmark ` ./valkey-benchmark -r 100000 -n 6000000 lpush my_list
__rand_int__`.
---------
Signed-off-by: naglera <anagler123@gmail.com>
Signed-off-by: naglera <58042354+naglera@users.noreply.github.com>
Co-authored-by: Viktor Söderqvist <viktor.soderqvist@est.tech>
Co-authored-by: Ping Xie <pingxie@outlook.com>
Co-authored-by: Madelyn Olson <madelyneolson@gmail.com>
This PR is 1 of 3 PRs intended to achieve the goal of 1 million requests
per second, as detailed by [dan touitou](https://github.com/touitou-dan)
in https://github.com/valkey-io/valkey/issues/22. This PR modifies the
IO threads to be fully asynchronous, which is a first and necessary step
to allow more work offloading and better utilization of the IO threads.
### Current IO threads state:
Valkey IO threads were introduced in Redis 6.0 to allow better
utilization of multi-core machines. Before this, Redis was
single-threaded and could only use one CPU core for network and command
processing. The introduction of IO threads helps in offloading the IO
operations to multiple threads.
**Current IO Threads flow:**
1. Initialization: When Redis starts, it initializes a specified number
of IO threads. These threads are in addition to the main thread, each
thread starts with an empty list, the main thread will populate that
list in each event-loop with pending-read-clients or
pending-write-clients.
2. Read Phase: The main thread accepts incoming connections and reads
requests from clients. The reading of requests are offloaded to IO
threads. The main thread puts the clients ready-to-read in a list and
set the global io_threads_op to IO_THREADS_OP_READ, the IO threads pick
the clients up, perform the read operation and parse the first incoming
command.
3. Command Processing: After reading the requests, command processing is
still single-threaded and handled by the main thread.
4. Write Phase: Similar to the read phase, the write phase is also be
offloaded to IO threads. The main thread prepares the response in the
clients’ output buffer then the main thread puts the client in the list,
and sets the global io_threads_op to the IO_THREADS_OP_WRITE. The IO
threads then pick the clients up and perform the write operation to send
the responses back to clients.
5. Synchronization: The main-thread communicate with the threads on how
many jobs left per each thread with atomic counter. The main-thread
doesn’t access the clients while being handled by the IO threads.
**Issues with current implementation:**
* Underutilized Cores: The current implementation of IO-threads leads to
the underutilization of CPU cores.
* The main thread remains responsible for a significant portion of
IO-related tasks that could be offloaded to IO-threads.
* When the main-thread is processing client’s commands, the IO threads
are idle for a considerable amount of time.
* Notably, the main thread's performance during the IO-related tasks is
constrained by the speed of the slowest IO-thread.
* Limited Offloading: Currently, Since the Main-threads waits
synchronously for the IO threads, the Threads perform only read-parse,
and write operations, with parsing done only for the first command. If
the threads can do work asynchronously we may offload more work to the
threads reducing the load from the main-thread.
* TLS: Currently, we don't support IO threads with TLS (where offloading
IO would be more beneficial) since TLS read/write operations are not
thread-safe with the current implementation.
### Suggested change
Non-blocking main thread - The main thread and IO threads will operate
in parallel to maximize efficiency. The main thread will not be blocked
by IO operations. It will continue to process commands independently of
the IO thread's activities.
**Implementation details**
**Inter-thread communication.**
* We use a static, lock-free ring buffer of fixed size (2048 jobs) for
the main thread to send jobs and for the IO to receive them. If the ring
buffer fills up, the main thread will handle the task itself, acting as
back pressure (in case IO operations are more expensive than command
processing). A static ring buffer is a better candidate than a dynamic
job queue as it eliminates the need for allocation/freeing per job.
* An IO job will be in the format: ` [void* function-call-back | void
*data] `where data is either a client to read/write from and the
function-ptr is the function to be called with the data for example
readQueryFromClient using this format we can use it later to offload
other types of works to the IO threads.
* The Ring buffer is one way from the main-thread to the IO thread, Upon
read/write event the main thread will send a read/write job then in
before sleep it will iterate over the pending read/write clients to
checking for each client if the IO threads has already finished handling
it. The IO thread signals it has finished handling a client read/write
by toggling an atomic flag read_state / write_state on the client
struct.
**Thread Safety**
As suggested in this solution, the IO threads are reading from and
writing to the clients' buffers while the main thread may access those
clients.
We must ensure no race conditions or unsafe access occurs while keeping
the Valkey code simple and lock free.
Minimal Action in the IO Threads
The main change is to limit the IO thread operations to the bare
minimum. The IO thread will access only the client's struct and only the
necessary fields in this struct.
The IO threads will be responsible for the following:
* Read Operation: The IO thread will only read and parse a single
command. It will not update the server stats, handle read errors, or
parsing errors. These tasks will be taken care of by the main thread.
* Write Operation: The IO thread will only write the available data. It
will not free the client's replies, handle write errors, or update the
server statistics.
To achieve this without code duplication, the read/write code has been
refactored into smaller, independent components:
* Functions that perform only the read/parse/write calls.
* Functions that handle the read/parse/write results.
This refactor accounts for the majority of the modifications in this PR.
**Client Struct Safe Access**
As we ensure that the IO threads access memory only within the client
struct, we need to ensure thread safety only for the client's struct's
shared fields.
* Query Buffer
* Command parsing - The main thread will not try to parse a command from
the query buffer when a client is offloaded to the IO thread.
* Client's memory checks in client-cron - The main thread will not
access the client query buffer if it is offloaded and will handle the
querybuf grow/shrink when the client is back.
* CLIENT LIST command - The main thread will busy-wait for the IO thread
to finish handling the client, falling back to the current behavior
where the main thread waits for the IO thread to finish their
processing.
* Output Buffer
* The IO thread will not change the client's bufpos and won't free the
client's reply lists. These actions will be done by the main thread on
the client's return from the IO thread.
* bufpos / block→used: As the main thread may change the bufpos, the
reply-block→used, or add/delete blocks to the reply list while the IO
thread writes, we add two fields to the client struct: io_last_bufpos
and io_last_reply_block. The IO thread will write until the
io_last_bufpos, which was set by the main-thread before sending the
client to the IO thread. If more data has been added to the cob in
between, it will be written in the next write-job. In addition, the main
thread will not trim or merge reply blocks while the client is
offloaded.
* Parsing Fields
* Client's cmd, argc, argv, reqtype, etc., are set during parsing.
* The main thread will indicate to the IO thread not to parse a cmd if
the client is not reset. In this case, the IO thread will only read from
the network and won't attempt to parse a new command.
* The main thread won't access the c→cmd/c→argv in the CLIENT LIST
command as stated before it will busy wait for the IO threads.
* Client Flags
* c→flags, which may be changed by the main thread in multiple places,
won't be accessed by the IO thread. Instead, the main thread will set
the c→io_flags with the information necessary for the IO thread to know
the client's state.
* Client Close
* On freeClient, the main thread will busy wait for the IO thread to
finish processing the client's read/write before proceeding to free the
client.
* Client's Memory Limits
* The IO thread won't handle the qb/cob limits. In case a client crosses
the qb limit, the IO thread will stop reading for it, letting the main
thread know that the client crossed the limit.
**TLS**
TLS is currently not supported with IO threads for the following
reasons:
1. Pending reads - If SSL has pending data that has already been read
from the socket, there is a risk of not calling the read handler again.
To handle this, a list is used to hold the pending clients. With IO
threads, multiple threads can access the list concurrently.
2. Event loop modification - Currently, the TLS code
registers/unregisters the file descriptor from the event loop depending
on the read/write results. With IO threads, multiple threads can modify
the event loop struct simultaneously.
3. The same client can be sent to 2 different threads concurrently
(https://github.com/redis/redis/issues/12540).
Those issues were handled in the current PR:
1. The IO thread only performs the read operation. The main thread will
check for pending reads after the client returns from the IO thread and
will be the only one to access the pending list.
2. The registering/unregistering of events will be similarly postponed
and handled by the main thread only.
3. Each client is being sent to the same dedicated thread (c→id %
num_of_threads).
**Sending Replies Immediately with IO threads.**
Currently, after processing a command, we add the client to the
pending_writes_list. Only after processing all the clients do we send
all the replies. Since the IO threads are now working asynchronously, we
can send the reply immediately after processing the client’s requests,
reducing the command latency. However, if we are using AOF=always, we
must wait for the AOF buffer to be written, in which case we revert to
the current behavior.
**IO threads dynamic adjustment**
Currently, we use an all-or-nothing approach when activating the IO
threads. The current logic is as follows: if the number of pending write
clients is greater than twice the number of threads (including the main
thread), we enable all threads; otherwise, we enable none. For example,
if 8 IO threads are defined, we enable all 8 threads if there are 16
pending clients; else, we enable none.
It makes more sense to enable partial activation of the IO threads. If
we have 10 pending clients, we will enable 5 threads, and so on. This
approach allows for a more granular and efficient allocation of
resources based on the current workload.
In addition, the user will now be able to change the number of I/O
threads at runtime. For example, when decreasing the number of threads
from 4 to 2, threads 3 and 4 will be closed after flushing their job
queues.
**Tests**
Currently, we run the io-threads tests with 4 IO threads
(443d80f168/.github/workflows/daily.yml (L353)).
This means that we will not activate the IO threads unless there are 8
(threads * 2) pending write clients per single loop, which is unlikely
to happened in most of tests, meaning the IO threads are not currently
being tested.
To enforce the main thread to always offload work to the IO threads,
regardless of the number of pending events, we add an
events-per-io-thread configuration with a default value of 2. When set
to 0, this configuration will force the main thread to always offload
work to the IO threads.
When we offload every single read/write operation to the IO threads, the
IO-threads are running with 100% CPU when running multiple tests
concurrently some tests fail as a result of larger than expected command
latencies. To address this issue, we have to add some after or wait_for
calls to some of the tests to ensure they pass with IO threads as well.
Signed-off-by: Uri Yagelnik <uriy@amazon.com>
We added some clang-format off comments before we had decided on the
format configuration. Now, it turns out that turning formatting off is
often not necessary.
---------
Signed-off-by: Viktor Söderqvist <viktor.soderqvist@est.tech>
There are currently three block types: BLOCKED_WAIT, BLOCKED_WAITAOF,
and BLOCKED_WAIT_PREREPL, used to block clients executing `WAIT`,
`WAITAOF`, and `CLUSTER SETSLOT`, respectively. They share the same
workflow: the client is blocked until replication to the expected number
of replicas completes. However, they provide different responses
depending on the commands involved. Using distinct block types leads to
code duplication and reduced readability. This PR consolidates the three
types into a single WAIT type, differentiating them using the pending
command to ensure the appropriate response is returned.
Fix#427
---------
Signed-off-by: Ping Xie <pingxie@google.com>
This PR optimizes client query buffer handling in Valkey by introducing
a shared query buffer that is used by default for client reads. This
reduces memory usage by ~20KB per client by avoiding allocations for
most clients using short (<16KB) complete commands. For larger or
partial commands, the client still gets its own private buffer.
The primary changes are:
* Adding a shared query buffer `shared_qb` that clients use by default
* Modifying client querybuf initialization and reset logic
* Copying any partial query from shared to private buffer before command
execution
* Freeing idle client query buffers when empty to allow reuse of shared
buffer
* Master client query buffers are kept private as their contents need to
be preserved for replication stream
In addition to the memory savings, this change shows a 3% improvement in
latency and throughput when running with 1000 active clients.
The memory reduction may also help reduce the need to evict clients when
reaching max memory limit, as the query buffer is the main memory
consumer per client.
---------
Signed-off-by: Uri Yagelnik <uriy@amazon.com>
Signed-off-by: Madelyn Olson <madelyneolson@gmail.com>
Co-authored-by: Madelyn Olson <madelyneolson@gmail.com>
The replica sends its version when initiating replication, in
pipeline with other REPLCONF commands.
The primary stores it in the client struct. Other fields are made
smaller to avoid making the client struct consume more memory.
Fixes#414.
---------
Signed-off-by: Viktor Söderqvist <viktor.soderqvist@est.tech>
- Replaces custom atomics logic with C11 default atomics logic.
- Drops "atomicvar_api" field from server info
Closes#485
---------
Signed-off-by: adetunjii <adetunjithomas1@outlook.com>
Signed-off-by: Samuel Adetunji <adetunjithomas1@outlook.com>
Co-authored-by: teej4y <samuel.adetunji@prunny.com>
I have validated that these settings closely match the existing coding
style with one major exception on `BreakBeforeBraces`, which will be
`Attach` going forward. The mixed `BreakBeforeBraces` styles in the
current codebase are hard to imitate and also very odd IMHO - see below
```
if (a == 1) { /*Attach */
}
```
```
if (a == 1 ||
b == 2)
{ /* Why? */
}
```
Please do NOT merge just yet. Will add the github action next once the
style is reviewed/approved.
---------
Signed-off-by: Ping Xie <pingxie@google.com>
This is a preparation for adding clang-format.
These comments prevent automatic formatting in some places. With these
exceptions, we will be able to run clang-format on the rest of the code.
This is a preparation for #323.
---------
Signed-off-by: Viktor Söderqvist <viktor.soderqvist@est.tech>
This patch try to do following things:
1. Rename `redis_*` and `REDIS_*` macros defined in config.h to
`valkey_*`, `VALKEY_*` and update associated used files. (`redis_fstat`,
`redis_fsync`, `REDIS_THREAD_STACK_SIZE`, etc.)
2. Remove the leading double underscore for guard macro in config.h.
---------
Signed-off-by: Lipeng Zhu <lipeng.zhu@intel.com>
Low-risk error replies containing "Redis" are changed.
In most cases, the word "Redis" is simply removed from the error message,
such as in "This Redis instance is not configured to use an ACL file. (...)",
the message is changed to "This instance is not configured to use an ACL
file. (...)".
Additionally, error replies from `redis.call` in a Lua script are
affected, such as
* "Please specify at least one argument for this redis lib call"
* "Wrong number of args calling Redis command from script"
* "Unknown Redis command called from script"
* "Invalid command passed to redis.acl_check_cmd()"
The name Redis is simply removed from these error message. In the last
one above, "redis.acl_check_cmd()" is replaced by
"server.acl_check_cmd()" in the error message.
The following error replies are considered high of causing problems for
clients, so they are not changed in this commit:
* (not in scope) "-MISCONF Redis is configured to save RDB snapshots
(...)"
* (not in scope) "-LOADING Redis is loading the dataset in memory"
* (not in scope) "-BUSY Redis is busy running a script (...)"
Fixes#204
---------
Signed-off-by: Viktor Söderqvist <viktor.soderqvist@est.tech>
This includes comments used for module API documentation.
* Strategy for replacement: Regex search: `(//|/\*| \*|#).* ("|\()?(r|R)edis( |\.
|'|\n|,|-|\)|")(?!nor the names of its contributors)(?!Ltd.)(?!Labs)(?!Contributors.)`
* Don't edit copyright comments
* Replace "Redis version X.X" -> "Redis OSS version X.X" to distinguish
from newly licensed repository
* Replace "Redis Object" -> "Object"
* Exclude markdown for now
* Don't edit Lua scripting comments referring to redis.X API
* Replace "Redis Protocol" -> "RESP"
* Replace redis-benchmark, -cli, -server, -check-aof/rdb with "valkey-"
prefix
* Most other places, I use best judgement to either remove "Redis", or
replace with "the server" or "server"
Fixes#148
---------
Signed-off-by: Jacob Murphy <jkmurphy@google.com>
Signed-off-by: Viktor Söderqvist <viktor.soderqvist@est.tech>
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>
