zipmap to hash conversion in HSET

Changelog

@@ -1,3 +1,8 @@
+2010-03-14 max zipmap entries and max zipmap value parameters added into INFO output
+2010-03-14 HDEL and some improvement in DEBUG OBJECT command
+2010-03-14 Append only file support for hashes
+2010-03-13 utility to check rdb files for unprocessable opcodes
+2010-03-12 A minor fix and a few debug messages removed
 2010-03-12 Applied the replication bug patch provided by Jeremy Zawodny, removing temp file collision after the slave got the dump.rdb file in the SYNC stage
 2010-03-11 Fix for HGET against non Hash type, debug messages used to understand a bit better a corrupted rdb file
 2010-03-09 fix: use zmalloc instead of malloc

redis.c

@@ -5932,6 +5932,20 @@ static void hsetCommand(redisClient *c) {
             return;
         }
     }
+    /* We want to convert the zipmap into an hash table right now if the
+     * entry to be added is too big. Note that we check if the object
+     * is integer encoded before to try fetching the length in the test below.
+     * This is because integers are small, but currently stringObjectLen()
+     * performs a slow conversion: not worth it. */
+    if (o->encoding == REDIS_ENCODING_ZIPMAP &&
+        ((c->argv[2]->encoding == REDIS_ENCODING_RAW &&
+          sdslen(c->argv[2]->ptr) > server.hash_max_zipmap_value) ||
+         (c->argv[3]->encoding == REDIS_ENCODING_RAW &&
+          sdslen(c->argv[3]->ptr) > server.hash_max_zipmap_value)))
+    {
+        convertToRealHash(o);
+    }
+
     if (o->encoding == REDIS_ENCODING_ZIPMAP) {
         unsigned char *zm = o->ptr;
         robj *valobj = getDecodedObject(c->argv[3]);
@@ -5940,7 +5954,16 @@ static void hsetCommand(redisClient *c) {
             valobj->ptr,sdslen(valobj->ptr),&update);
         decrRefCount(valobj);
         o->ptr = zm;
+
+        /* And here there is the second check for hash conversion...
+         * we want to do it only if the operation was not just an update as
+         * zipmapLen() is O(N). */
+        if (!update && zipmapLen(zm) > server.hash_max_zipmap_entries)
+            convertToRealHash(o);
     } else {
+        tryObjectEncoding(c->argv[2]);
+        /* note that c->argv[3] is already encoded, as the latest arg
+         * of a bulk command is always integer encoded if possible. */
         if (dictAdd(o->ptr,c->argv[2],c->argv[3]) == DICT_OK) {
             incrRefCount(c->argv[2]);
         } else {