Use safe dictionary iterator from KEYS

Every matched key in a KEYS call is checked for expiration. When the key
is set to expire, the call to `getExpire` will assert that the key also
exists in the main dictionary. This in turn causes a rehashing step to
be executed. Rehashing a dictionary when there is an iterator active may
result in the iterator emitting duplicate entries, or not emitting some
entries at all. By using a safe iterator, the rehash step is omitted.

diff --git a/src/db.c b/src/db.c
index 3c75f6bad61d424e08318b359bee51c63746f1ba..e65106a583c1117c197b6a064537f1cb25d9936b 100644 (file)
--- a/src/db.c
+++ b/src/db.c
@@ -255,7 +255,7 @@ void keysCommand(redisClient *c) {
     unsigned long numkeys = 0;
     void *replylen = addDeferredMultiBulkLength(c);
 
-    di = dictGetIterator(c->db->dict);
+    di = dictGetSafeIterator(c->db->dict);
     allkeys = (pattern[0] == '*' && pattern[1] == '\0');
     while((de = dictNext(di)) != NULL) {
         sds key = dictGetKey(de);