Introduce setKeyWithDictEntry, which is like setKey(), but accepts an optional dictEntry input: Avoids the second dictFind in SET command

fcostaoliveira · fcostaoliveira · commit 93fae760a082 · 2024-08-30T13:42:26.000+01:00
diff --git a/src/db.c b/src/db.c
@@ -323,6 +323,13 @@ void dbReplaceValueWithDictEntry(redisDb *db, robj *key, robj *val, dictEntry *d
  * The client 'c' argument may be set to NULL if the operation is performed
  * in a context where there is no clear client performing the operation. */
 void setKey(client *c, redisDb *db, robj *key, robj *val, int flags) {
+    setKeyWithDictEntry(c,db,key,val,flags,NULL);
+}
+
+/* Like setKey(), but accepts an optional dictEntry input,
+ * which can be used if we already have one, thus saving the dictFind call.
+ */
+void setKeyWithDictEntry(client *c, redisDb *db, robj *key, robj *val, int flags, dictEntry *de) {
     int keyfound = 0;
 
     if (flags & SETKEY_ALREADY_EXIST)
@@ -337,7 +344,7 @@ void setKey(client *c, redisDb *db, robj *key, robj *val, int flags) {
     } else if (keyfound<0) {
         dbAddInternal(db,key,val,1);
     } else {
-        dbSetValue(db,key,val,1,NULL);
+        dbSetValue(db,key,val,1,de);
     }
     incrRefCount(val);
     if (!(flags & SETKEY_KEEPTTL)) removeExpire(db,key);
diff --git a/src/server.h b/src/server.h
@@ -3387,6 +3387,7 @@ void dbReplaceValueWithDictEntry(redisDb *db, robj *key, robj *val, dictEntry *d
 #define SETKEY_DOESNT_EXIST 8
 #define SETKEY_ADD_OR_UPDATE 16 /* Key most likely doesn't exists */
 void setKey(client *c, redisDb *db, robj *key, robj *val, int flags);
+void setKeyWithDictEntry(client *c, redisDb *db, robj *key, robj *val, int flags, dictEntry *de);
 robj *dbRandomKey(redisDb *db);
 int dbGenericDelete(redisDb *db, robj *key, int async, int flags);
 int dbSyncDelete(redisDb *db, robj *key);
diff --git a/src/t_string.c b/src/t_string.c
@@ -73,7 +73,9 @@ void setGenericCommand(client *c, int flags, robj *key, robj *val, robj *expire,
         if (getGenericCommand(c) == C_ERR) return;
     }
 
-    found = (lookupKeyWrite(c->db,key) != NULL);
+    dictEntry *de = dbFind(c->db, key->ptr);
+    robj *o = lookupKeyWriteWithDictEntry(c->db,key,de);
+    found = (o != NULL);
 
     if ((flags & OBJ_SET_NX && found) ||
         (flags & OBJ_SET_XX && !found))
@@ -88,7 +90,7 @@ void setGenericCommand(client *c, int flags, robj *key, robj *val, robj *expire,
     setkey_flags |= ((flags & OBJ_KEEPTTL) || expire) ? SETKEY_KEEPTTL : 0;
     setkey_flags |= found ? SETKEY_ALREADY_EXIST : SETKEY_DOESNT_EXIST;
 
-    setKey(c,c->db,key,val,setkey_flags);
+    setKeyWithDictEntry(c,c->db,key,val,setkey_flags,de);
     server.dirty++;
     notifyKeyspaceEvent(NOTIFY_STRING,"set",key,c->db->id);
 
