From 2248eaacac991a851c55dbb33bc328b7d6f780a8 Mon Sep 17 00:00:00 2001
From: "zhaozhao.zz" <zhaozhao.zz@alibaba-inc.com>
Date: Tue, 12 Jun 2018 23:57:55 +0800
Subject: [PATCH] resize query buffer more accurately

1. querybuf_peak has not been updated correctly in readQueryFromClient.
2. qbuf shrinking uses sdsalloc instead of sdsAllocSize

see more details in issue #4983
---
 src/networking.c | 4 +++-
 src/server.c     | 2 +-
 2 files changed, 4 insertions(+), 2 deletions(-)

diff --git a/src/networking.c b/src/networking.c
index 6ab16e293..805f3f0e9 100644
--- a/src/networking.c
+++ b/src/networking.c
@@ -2147,7 +2147,6 @@ void readQueryFromClient(connection *conn) {
     }
 
     qblen = sdslen(c->querybuf);
-    if (c->querybuf_peak < qblen) c->querybuf_peak = qblen;
     if (big_arg || sdsalloc(c->querybuf) < PROTO_IOBUF_LEN) {
         /* When reading a BIG_ARG we won't be reading more than that one arg
          * into the query buffer, so we don't need to pre-allocate more than we
@@ -2187,6 +2186,9 @@ void readQueryFromClient(connection *conn) {
     }
 
     sdsIncrLen(c->querybuf,nread);
+    qblen = sdslen(c->querybuf);
+    if (c->querybuf_peak < qblen) c->querybuf_peak = qblen;
+
     c->lastinteraction = server.unixtime;
     if (c->flags & CLIENT_MASTER) c->read_reploff += nread;
     atomicIncr(server.stat_net_input_bytes, nread);
diff --git a/src/server.c b/src/server.c
index dbc0a04e2..27a2f6c46 100644
--- a/src/server.c
+++ b/src/server.c
@@ -1664,7 +1664,7 @@ long long getInstantaneousMetric(int metric) {
  *
  * The function always returns 0 as it never terminates the client. */
 int clientsCronResizeQueryBuffer(client *c) {
-    size_t querybuf_size = sdsAllocSize(c->querybuf);
+    size_t querybuf_size = sdsalloc(c->querybuf);
     time_t idletime = server.unixtime - c->lastinteraction;
 
     /* There are two conditions to resize the query buffer: