From e9f312e08708e6b719ecd6b5eafb9ec2fefad16e Mon Sep 17 00:00:00 2001
From: Chen Tianjie <chentianjie.ctj@alibaba-inc.com>
Date: Wed, 1 Nov 2023 10:57:24 +0800
Subject: [PATCH] Change stat_client_qbuf_limit_disconnections to atomic.
 (#12711)

In #12476 server.stat_client_qbuf_limit_disconnections was added. It is written in readQueryFromClient, which may be called by multiple threads when io-threads and io-threads-do-reads are turned on. Somehow we missed to make it an atomic variable.
---
 src/networking.c | 2 +-
 src/server.c     | 6 ++++--
 src/server.h     | 2 +-
 3 files changed, 6 insertions(+), 4 deletions(-)

diff --git a/src/networking.c b/src/networking.c
index a77f34759..718271aec 100644
--- a/src/networking.c
+++ b/src/networking.c
@@ -2706,7 +2706,7 @@ void readQueryFromClient(connection *conn) {
         sdsfree(ci);
         sdsfree(bytes);
         freeClientAsync(c);
-        server.stat_client_qbuf_limit_disconnections++;
+        atomicIncr(server.stat_client_qbuf_limit_disconnections, 1);
         goto done;
     }
 
diff --git a/src/server.c b/src/server.c
index 3743fc09e..83c2edc77 100644
--- a/src/server.c
+++ b/src/server.c
@@ -2599,7 +2599,7 @@ void resetServerStats(void) {
     atomicSet(server.stat_total_reads_processed, 0);
     server.stat_io_writes_processed = 0;
     atomicSet(server.stat_total_writes_processed, 0);
-    server.stat_client_qbuf_limit_disconnections = 0;
+    atomicSet(server.stat_client_qbuf_limit_disconnections, 0);
     server.stat_client_outbuf_limit_disconnections = 0;
     for (j = 0; j < STATS_METRIC_COUNT; j++) {
         server.inst_metric[j].idx = 0;
@@ -5831,12 +5831,14 @@ sds genRedisInfoString(dict *section_dict, int all_sections, int everything) {
             (long long) elapsedUs(server.stat_last_eviction_exceeded_time): 0;
         long long current_active_defrag_time = server.stat_last_active_defrag_time ?
             (long long) elapsedUs(server.stat_last_active_defrag_time): 0;
+        long long stat_client_qbuf_limit_disconnections;
         atomicGet(server.stat_total_reads_processed, stat_total_reads_processed);
         atomicGet(server.stat_total_writes_processed, stat_total_writes_processed);
         atomicGet(server.stat_net_input_bytes, stat_net_input_bytes);
         atomicGet(server.stat_net_output_bytes, stat_net_output_bytes);
         atomicGet(server.stat_net_repl_input_bytes, stat_net_repl_input_bytes);
         atomicGet(server.stat_net_repl_output_bytes, stat_net_repl_output_bytes);
+        atomicGet(server.stat_client_qbuf_limit_disconnections, stat_client_qbuf_limit_disconnections);
 
         if (sections++) info = sdscat(info,"\r\n");
         info = sdscatprintf(info, "# Stats\r\n" FMTARGS(
@@ -5888,7 +5890,7 @@ sds genRedisInfoString(dict *section_dict, int all_sections, int everything) {
             "total_writes_processed:%lld\r\n", stat_total_writes_processed,
             "io_threaded_reads_processed:%lld\r\n", server.stat_io_reads_processed,
             "io_threaded_writes_processed:%lld\r\n", server.stat_io_writes_processed,
-            "client_query_buffer_limit_disconnections:%lld\r\n", server.stat_client_qbuf_limit_disconnections,
+            "client_query_buffer_limit_disconnections:%lld\r\n", stat_client_qbuf_limit_disconnections,
             "client_output_buffer_limit_disconnections:%lld\r\n", server.stat_client_outbuf_limit_disconnections,
             "reply_buffer_shrinks:%lld\r\n", server.stat_reply_buffer_shrinks,
             "reply_buffer_expands:%lld\r\n", server.stat_reply_buffer_expands,
diff --git a/src/server.h b/src/server.h
index 5ededdf3f..4a3eedc4c 100644
--- a/src/server.h
+++ b/src/server.h
@@ -1707,7 +1707,7 @@ struct redisServer {
     long long stat_io_writes_processed; /* Number of write events processed by IO / Main threads */
     redisAtomic long long stat_total_reads_processed; /* Total number of read events processed */
     redisAtomic long long stat_total_writes_processed; /* Total number of write events processed */
-    long long stat_client_qbuf_limit_disconnections;  /* Total number of clients reached query buf length limit */
+    redisAtomic long long stat_client_qbuf_limit_disconnections;  /* Total number of clients reached query buf length limit */
     long long stat_client_outbuf_limit_disconnections;  /* Total number of clients reached output buf length limit */
     /* The following two are used to track instantaneous metrics, like
      * number of operations per second, network traffic. */