Embed key into dict entry

src/db.c

@@ -204,7 +204,6 @@ static void dbAddInternal(serverDb *db, robj *key, robj *val, int update_if_exis
         return;
     }
     serverAssertWithInfo(NULL, key, de != NULL);
-    kvstoreDictSetKey(db->keys, slot, de, sdsdup(key->ptr));
     initObjectLRUOrLFU(val);
     kvstoreDictSetVal(db->keys, slot, de, val);
     signalKeyAsReady(db, key, val->type);
@@ -241,15 +240,14 @@ int getKeySlot(sds key) {
 
 /* This is a special version of dbAdd() that is used only when loading
  * keys from the RDB file: the key is passed as an SDS string that is
- * retained by the function (and not freed by the caller).
+ * copied by the function and freed by the caller.
  *
  * Moreover this function will not abort if the key is already busy, to
  * give more control to the caller, nor will signal the key as ready
  * since it is not useful in this context.
  *
- * The function returns 1 if the key was added to the database, taking
- * ownership of the SDS string, otherwise 0 is returned, and is up to the
- * caller to free the SDS string. */
+ * The function returns 1 if the key was added to the database, making a
+ * copy of the SDS string, otherwise 0 is returned, The caller should free the SDS string. */
 int dbAddRDBLoad(serverDb *db, sds key, robj *val) {
     int slot = getKeySlot(key);
     dictEntry *de = kvstoreDictAddRaw(db->keys, slot, key, NULL);

src/debug.c

@@ -864,7 +864,7 @@ void debugCommand(client *c) {
         sds sizes = sdsempty();
         sizes = sdscatprintf(sizes, "bits:%d ", (sizeof(void *) == 8) ? 64 : 32);
         sizes = sdscatprintf(sizes, "robj:%d ", (int)sizeof(robj));
-        sizes = sdscatprintf(sizes, "dictentry:%d ", (int)dictEntryMemUsage());
+        sizes = sdscatprintf(sizes, "dictentry:%d ", (int)dictEntryMemUsage(NULL));
         sizes = sdscatprintf(sizes, "sdshdr5:%d ", (int)sizeof(struct sdshdr5));
         sizes = sdscatprintf(sizes, "sdshdr8:%d ", (int)sizeof(struct sdshdr8));
         sizes = sdscatprintf(sizes, "sdshdr16:%d ", (int)sizeof(struct sdshdr16));

src/defrag.c

@@ -41,6 +41,7 @@
 typedef struct defragCtx {
     void *privdata;
     int slot;
+    void *aux;
 } defragCtx;
 
 typedef struct defragPubSubCtx {
@@ -75,6 +76,36 @@ void *activeDefragAlloc(void *ptr) {
     return newptr;
 }
 
+/* This method captures the expiry db dict entry which refers to data stored in keys db dict entry. */
+void defragEntryStartCbForKeys(void *ctx, void *oldptr) {
+    defragCtx *defragctx = (defragCtx *)ctx;
+    serverDb *db = defragctx->privdata;
+    sds oldsds = (sds)dictGetKey((dictEntry *)oldptr);
+    int slot = defragctx->slot;
+    if (kvstoreDictSize(db->expires, slot)) {
+        dictEntry *expire_de = kvstoreDictFind(db->expires, slot, oldsds);
+        defragctx->aux = expire_de;
+    }
+}
+
+/* This method updates the key of expiry db dict entry. The key might be no longer valid
+ * as it could have been cleaned up during the defrag-realloc of the main dictionary. */
+void defragEntryFinishCbForKeys(void *ctx, void *newptr) {
+    defragCtx *defragctx = (defragCtx *)ctx;
+    dictEntry *expire_de = (dictEntry *)defragctx->aux;
+    /* Item doesn't have TTL associated to it. */
+    if (!expire_de) return;
+    /* No reallocation happened. */
+    if (!newptr) {
+        expire_de = NULL;
+        return;
+    }
+    serverDb *db = defragctx->privdata;
+    sds newsds = (sds)dictGetKey((dictEntry *)newptr);
+    int slot = defragctx->slot;
+    kvstoreDictSetKey(db->expires, slot, expire_de, newsds);
+}
+
 /*Defrag helper for sds strings
  *
  * returns NULL in case the allocation wasn't moved.
@@ -650,25 +681,10 @@ void defragModule(serverDb *db, dictEntry *kde) {
 /* for each key we scan in the main dict, this function will attempt to defrag
  * all the various pointers it has. */
 void defragKey(defragCtx *ctx, dictEntry *de) {
-    sds keysds = dictGetKey(de);
-    robj *newob, *ob;
-    unsigned char *newzl;
-    sds newsds;
     serverDb *db = ctx->privdata;
     int slot = ctx->slot;
-    /* Try to defrag the key name. */
-    newsds = activeDefragSds(keysds);
-    if (newsds) {
-        kvstoreDictSetKey(db->keys, slot, de, newsds);
-        if (kvstoreDictSize(db->expires, slot)) {
-            /* We can't search in db->expires for that key after we've released
-             * the pointer it holds, since it won't be able to do the string
-             * compare, but we can find the entry using key hash and pointer. */
-            uint64_t hash = kvstoreGetHash(db->expires, newsds);
-            dictEntry *expire_de = kvstoreDictFindEntryByPtrAndHash(db->expires, slot, keysds, hash);
-            if (expire_de) kvstoreDictSetKey(db->expires, slot, expire_de, newsds);
-        }
-    }
+    robj *newob, *ob;
+    unsigned char *newzl;
 
     /* Try to defrag robj and / or string value. */
     ob = dictGetVal(de);
@@ -984,7 +1000,9 @@ void activeDefragCycle(void) {
     endtime = start + timelimit;
     latencyStartMonitor(latency);
 
-    dictDefragFunctions defragfns = {.defragAlloc = activeDefragAlloc};
+    dictDefragFunctions defragfns = {.defragAlloc = activeDefragAlloc,
+                                     .defragEntryStartCb = defragEntryStartCbForKeys,
+                                     .defragEntryFinishCb = defragEntryFinishCbForKeys};
     do {
         /* if we're not continuing a scan from the last call or loop, start a new one */
         if (!defrag_stage && !defrag_cursor && (slot < 0)) {