From: antirez <antirez@gmail.com>
Date: Wed, 31 Oct 2012 08:23:05 +0000 (+0100)
Subject: Invert two sides of if expression in SET to avoid a lookup.
X-Git-Url: https://git.saurik.com/redis.git/commitdiff_plain/4d9bd5353027561039dc4583c794c8cfec30202c?hp=5bf0997ff879bf8668939d6b9e8a6eb877750c09

Invert two sides of if expression in SET to avoid a lookup.

Because of the short circuit behavior of && inverting the two sides of
the if expression avoids an hash table lookup if the non-EX variant of
SET is called.

Thanks to Weibin Yao (@yaoweibin on github) for spotting this.
---

diff --git a/src/t_string.c b/src/t_string.c
index 1e29a613..ba427961 100644
--- a/src/t_string.c
+++ b/src/t_string.c
@@ -26,7 +26,7 @@ void setGenericCommand(redisClient *c, int nx, robj *key, robj *val, robj *expir
         if (unit == UNIT_SECONDS) milliseconds *= 1000;
     }
 
-    if (lookupKeyWrite(c->db,key) != NULL && nx) {
+    if (nx && lookupKeyWrite(c->db,key) != NULL) {
         addReply(c,shared.czero);
         return;
     }