Isolate the persistent parts of the database from the runtime parts

Former-commit-id: 08995b065cb0ed6df16528e73c7acb28bcf3c1f4

src/db.cpp

@@ -41,7 +41,6 @@
 
 int keyIsExpired(redisDb *db, robj *key);
 int expireIfNeeded(redisDb *db, robj *key, robj *o);
-void dbOverwriteCore(redisDb *db, dictEntry *de, robj *key, robj *val, bool fUpdateMvcc, bool fRemoveExpire);
 
 /* Update LFU when an object is accessed.
  * Firstly, decrement the counter if the decrement time is reached.
@@ -57,8 +56,7 @@ void updateExpire(redisDb *db, sds key, robj *valOld, robj *valNew)
     serverAssert(valOld->FExpires());
     serverAssert(!valNew->FExpires());
     
-    auto itr = db->setexpire->find(key);
+    serverAssert(db->FKeyExpires((const char*)key));
-    serverAssert(itr != db->setexpire->end());
     
     valNew->SetFExpires(true);
     valOld->SetFExpires(false);
@@ -70,8 +68,9 @@ void updateExpire(redisDb *db, sds key, robj *valOld, robj *valNew)
  * implementations that should instead rely on lookupKeyRead(),
  * lookupKeyWrite() and lookupKeyReadWithFlags(). */
 static robj *lookupKey(redisDb *db, robj *key, int flags) {
-    robj *val = db->find(key);
+    auto itr = db->find(key);
-    if (val) {
+    if (itr) {
+        robj *val = itr.val();
         /* Update the access time for the ageing algorithm.
          * Don't do it if we have a saving child, as this will trigger
          * a copy on write madness. */
@@ -193,13 +192,13 @@ robj *lookupKeyWriteOrReply(client *c, robj *key, robj *reply) {
     return o;
 }
 
-int dbAddCore(redisDb *db, robj *key, robj *val) {
+bool dbAddCore(redisDb *db, robj *key, robj *val) {
     serverAssert(!val->FExpires());
     sds copy = sdsdup(szFromObj(key));
-    int retval = dictAdd(db->pdict, copy, val);
+    bool fInserted = db->insert(copy, val);
     val->mvcc_tstamp = key->mvcc_tstamp = getMvccTstamp();
 
-    if (retval == DICT_OK)
+    if (fInserted)
     {
         if (val->type == OBJ_LIST ||
             val->type == OBJ_ZSET)
@@ -211,7 +210,7 @@ int dbAddCore(redisDb *db, robj *key, robj *val) {
         sdsfree(copy);
     }
 
-    return retval;
+    return fInserted;
 }
 
 /* Add the key to the DB. It's up to the caller to increment the reference
@@ -220,23 +219,22 @@ int dbAddCore(redisDb *db, robj *key, robj *val) {
  * The program is aborted if the key already exists. */
 void dbAdd(redisDb *db, robj *key, robj *val)
 {
-    int retval = dbAddCore(db, key, val);
+    bool fInserted = dbAddCore(db, key, val);
-    serverAssertWithInfo(NULL,key,retval == DICT_OK);
+    serverAssertWithInfo(NULL,key,fInserted);
 }
 
-void dbOverwriteCore(redisDb *db, dictEntry *de, robj *key, robj *val, bool fUpdateMvcc, bool fRemoveExpire)
+void redisDb::dbOverwriteCore(redisDb::iter itr, robj *key, robj *val, bool fUpdateMvcc, bool fRemoveExpire)
 {
-    dictEntry auxentry = *de;
+    robj *old = itr.val();
-    robj *old = (robj*)dictGetVal(de);
 
     if (old->FExpires()) {
         if (fRemoveExpire) {
-            removeExpire(db, key);
+            removeExpire(this, key);
         }
         else {
             if (val->getrefcount(std::memory_order_relaxed) == OBJ_SHARED_REFCOUNT)
                 val = dupStringObject(val);
-            updateExpire(db, (sds)dictGetKey(de), old, val);
+            updateExpire(this, itr.key(), old, val);
         }
     }
 
@@ -249,14 +247,12 @@ void dbOverwriteCore(redisDb *db, dictEntry *de, robj *key, robj *val, bool fUpd
         val->mvcc_tstamp = getMvccTstamp();
     }
 
-    dictSetVal(db->pdict, de, val);
+    if (g_pserver->lazyfree_lazy_server_del)
+        freeObjAsync(itr.val());
+    else
+        decrRefCount(itr.val());
 
-    if (g_pserver->lazyfree_lazy_server_del) {
+    m_persistentData.updateValue(itr, val);
-        freeObjAsync(old);
-        dictSetVal(db->pdict, &auxentry, NULL);
-    }
-
-    dictFreeVal(db->pdict, &auxentry);
 }
 
 /* Overwrite an existing key with a new value. Incrementing the reference
@@ -265,10 +261,10 @@ void dbOverwriteCore(redisDb *db, dictEntry *de, robj *key, robj *val, bool fUpd
  *
  * The program is aborted if the key was not already present. */
 void dbOverwrite(redisDb *db, robj *key, robj *val) {
-    dictEntry *de = dictFind(db->pdict,ptrFromObj(key));
+    auto itr = db->find(key);
 
-    serverAssertWithInfo(NULL,key,de != NULL);
+    serverAssertWithInfo(NULL,key,itr != nullptr);
-    dbOverwriteCore(db, de, key, val, !!g_pserver->fActiveReplica, false);
+    db->dbOverwriteCore(itr, key, val, !!g_pserver->fActiveReplica, false);
 }
 
 /* Insert a key, handling duplicate keys according to fReplace */
@@ -276,14 +272,14 @@ int dbMerge(redisDb *db, robj *key, robj *val, int fReplace)
 {
     if (fReplace)
     {
-        dictEntry *de = dictFind(db->pdict, ptrFromObj(key));
+        auto itr = db->find(key);
-        if (de == nullptr)
+        if (itr == nullptr)
-            return (dbAddCore(db, key, val) == DICT_OK);
+            return (dbAddCore(db, key, val) == true);
 
-        robj *old = (robj*)dictGetVal(de);
+        robj *old = itr.val();
         if (old->mvcc_tstamp <= val->mvcc_tstamp)
         {
-            dbOverwriteCore(db, de, key, val, false, true);
+            db->dbOverwriteCore(itr, key, val, false, true);
             return true;
         }
         
@@ -291,7 +287,7 @@ int dbMerge(redisDb *db, robj *key, robj *val, int fReplace)
     }
     else
     {
-        return (dbAddCore(db, key, val) == DICT_OK);
+        return (dbAddCore(db, key, val) == true);
     }
 }
 
@@ -304,11 +300,11 @@ int dbMerge(redisDb *db, robj *key, robj *val, int fReplace)
  *
  * All the new keys in the database should be created via this interface. */
 void setKey(redisDb *db, robj *key, robj *val) {
-    dictEntry *de = dictFind(db->pdict, ptrFromObj(key));
+    auto itr = db->find(key);
-    if (de == NULL) {
+    if (itr == NULL) {
         dbAdd(db,key,val);
     } else {
-        dbOverwriteCore(db,de,key,val,!!g_pserver->fActiveReplica,true);
+        db->dbOverwriteCore(itr,key,val,!!g_pserver->fActiveReplica,true);
     }
     incrRefCount(val);
     signalModifiedKey(db,key);
@@ -324,19 +320,19 @@ int dbExists(redisDb *db, robj *key) {
  * The function makes sure to return keys not already expired. */
 robj *dbRandomKey(redisDb *db) {
     int maxtries = 100;
-    bool allvolatile = db->size() == db->setexpire->size();
+    bool allvolatile = db->expireSize() == db->size();
 
     while(1) {
         sds key;
         robj *keyobj;
 
-        auto pair = db->random();
+        auto itr = db->random();
-        if (pair.first == NULL) return NULL;
+        if (itr == nullptr) return NULL;
 
-        key = (sds)pair.first;
+        key = itr.key();
         keyobj = createStringObject(key,sdslen(key));
 
-        if (pair.second->FExpires())
+        if (itr.val()->FExpires())
         {
             if (allvolatile && listLength(g_pserver->masters) && --maxtries == 0) {
                 /* If the DB is composed only of keys with an expire set,
@@ -351,7 +347,7 @@ robj *dbRandomKey(redisDb *db) {
             }
         }
             
-        if (pair.second->FExpires())
+        if (itr.val()->FExpires())
         {
              if (expireIfNeeded(db,keyobj)) {
                 decrRefCount(keyobj);
@@ -363,15 +359,16 @@ robj *dbRandomKey(redisDb *db) {
     }
 }
 
-/* Delete a key, value, and associated expiration entry if any, from the DB */
+bool redisDbPersistentData::syncDelete(robj *key)
-int dbSyncDelete(redisDb *db, robj *key) {
+{
     /* Deleting an entry from the expires dict will not free the sds of
      * the key, because it is shared with the main dictionary. */
 
-    dictEntry *de = dictFind(db->pdict, szFromObj(key));
+    auto itr = find(szFromObj(key));
-    if (de != nullptr && ((robj*)dictGetVal(de))->FExpires())
+    trackkey(szFromObj(key));
-        removeExpireCore(db, key, de);
+    if (itr != nullptr && itr.val()->FExpires())
-    if (dictDelete(db->pdict,ptrFromObj(key)) == DICT_OK) {
+        removeExpire(key, itr);
+    if (dictDelete(m_pdict,ptrFromObj(key)) == DICT_OK) {
         if (g_pserver->cluster_enabled) slotToKeyDel(key);
         return 1;
     } else {
@@ -379,6 +376,11 @@ int dbSyncDelete(redisDb *db, robj *key) {
     }
 }
 
+/* Delete a key, value, and associated expiration entry if any, from the DB */
+int dbSyncDelete(redisDb *db, robj *key) {
+    return db->m_persistentData.syncDelete(key);
+}
+
 /* This is a wrapper whose behavior depends on the Redis lazy free
  * configuration. Deletes the key synchronously or asynchronously. */
 int dbDelete(redisDb *db, robj *key) {
@@ -456,15 +458,7 @@ long long emptyDb(int dbnum, int flags, void(callback)(void*)) {
     }
 
     for (int j = startdb; j <= enddb; j++) {
-        removed += dictSize(g_pserver->db[j].pdict);
+        removed += g_pserver->db[j].clear(!!async, callback); 
-        if (async) {
-            emptyDbAsync(&g_pserver->db[j]);
-        } else {
-            dictEmpty(g_pserver->db[j].pdict,callback);
-            delete g_pserver->db[j].setexpire;
-            g_pserver->db[j].setexpire = new (MALLOC_LOCAL) expireset();
-            g_pserver->db[j].expireitr = g_pserver->db[j].setexpire->end();
-        }
     }
     if (g_pserver->cluster_enabled) {
         if (async) {
@@ -633,9 +627,9 @@ void randomkeyCommand(client *c) {
 }
 
 
-bool redisDb::iterate(std::function<bool(const char*, robj*)> fn)
+bool redisDbPersistentData::iterate(std::function<bool(const char*, robj*)> &fn)
 {
-    dictIterator *di = dictGetSafeIterator(pdict);
+    dictIterator *di = dictGetSafeIterator(m_pdict);
     dictEntry *de = nullptr;
     bool fResult = true;
     while((de = dictNext(di)) != nullptr)
@@ -806,7 +800,7 @@ void scanGenericCommand(client *c, robj_roptr o, unsigned long cursor) {
     /* Handle the case of a hash table. */
     ht = NULL;
     if (o == nullptr) {
-        ht = c->db->pdict;
+        ht = c->db->dictUnsafe();
     } else if (o->type == OBJ_SET && o->encoding == OBJ_ENCODING_HT) {
         ht = (dict*)ptrFromObj(o);
     } else if (o->type == OBJ_HASH && o->encoding == OBJ_ENCODING_HT) {
@@ -1159,17 +1153,14 @@ int dbSwapDatabases(int id1, int id2) {
     /* Swap hash tables. Note that we don't swap blocking_keys,
      * ready_keys and watched_keys, since we want clients to
      * remain in the same DB they were. */
-    db1->pdict = db2->pdict;
+    redisDbPersistentData::swap(&db1->m_persistentData, &db2->m_persistentData);
-    db1->setexpire = db2->setexpire;
-    db1->expireitr = db2->expireitr;
     db1->avg_ttl = db2->avg_ttl;
     db1->last_expire_set = db2->last_expire_set;
+    db1->expireitr = db2->expireitr;
 
-    db2->pdict = aux.pdict;
-    db2->setexpire = aux.setexpire;
-    db2->expireitr = aux.expireitr;
     db2->avg_ttl = aux.avg_ttl;
     db2->last_expire_set = aux.last_expire_set;
+    db2->expireitr = aux.expireitr;
 
     /* Now we need to handle clients blocked on lists: as an effect
      * of swapping the two DBs, a client that was waiting for list
@@ -1218,23 +1209,24 @@ void swapdbCommand(client *c) {
  * Expires API
  *----------------------------------------------------------------------------*/
 int removeExpire(redisDb *db, robj *key) {
-    dictEntry *de = dictFind(db->pdict,ptrFromObj(key));
+    auto itr = db->find(key);
-    return removeExpireCore(db, key, de);
+    return db->m_persistentData.removeExpire(key, itr);
 }
-int removeExpireCore(redisDb *db, robj *key, dictEntry *de) {
+int redisDbPersistentData::removeExpire(robj *key, dict_iter itr) {
     /* An expire may only be removed if there is a corresponding entry in the
      * main dict. Otherwise, the key will never be freed. */
-    serverAssertWithInfo(NULL,key,de != NULL);
+    serverAssertWithInfo(NULL,key,itr != nullptr);
 
-    robj *val = (robj*)dictGetVal(de);
+    robj *val = itr.val();
     if (!val->FExpires())
         return 0;
 
-    auto itr = db->setexpire->find((sds)dictGetKey(de));
+    auto itrExpire = m_setexpire->find(itr.key());
-    serverAssert(itr != db->setexpire->end());
+    serverAssert(itrExpire != m_setexpire->end());
-    serverAssert(itr->key() == (sds)dictGetKey(de));
+    serverAssert(itrExpire->key() == itr.key());
-    db->setexpire->erase(itr);
+    m_setexpire->erase(itrExpire);
     val->SetFExpires(false);
+    trackkey(key);
     return 1;
 }
 
@@ -1243,49 +1235,23 @@ int removeExpireCore(redisDb *db, robj *key, dictEntry *de) {
  * to NULL. The 'when' parameter is the absolute unix time in milliseconds
  * after which the key will no longer be considered valid. */
 void setExpire(client *c, redisDb *db, robj *key, robj *subkey, long long when) {
-    dictEntry *kde;
-
     serverAssert(GlobalLocksAcquired());
 
-    /* Reuse the sds from the main dict in the expire dict */
-    kde = dictFind(db->pdict,ptrFromObj(key));
-    serverAssertWithInfo(NULL,key,kde != NULL);
-
-    if (((robj*)dictGetVal(kde))->getrefcount(std::memory_order_relaxed) == OBJ_SHARED_REFCOUNT)
-    {
-        // shared objects cannot have the expire bit set, create a real object
-        dictSetVal(db->pdict, kde, dupStringObject((robj*)dictGetVal(kde)));
-    }
-
     /* Update TTL stats (exponential moving average) */
     /*  Note: We never have to update this on expiry since we reduce it by the current elapsed time here */
     long long now = g_pserver->mstime;
     db->avg_ttl -= (now - db->last_expire_set); // reduce the TTL by the time that has elapsed
-    if (db->setexpire->empty())
+    if (db->expireSize() == 0)
         db->avg_ttl = 0;
     else
-        db->avg_ttl -= db->avg_ttl / db->setexpire->size(); // slide one entry out the window
+        db->avg_ttl -= db->avg_ttl / db->expireSize(); // slide one entry out the window
     if (db->avg_ttl < 0)
         db->avg_ttl = 0;    // TTLs are never negative
-    db->avg_ttl += (double)(when-now) / (db->setexpire->size()+1);    // add the new entry
+    db->avg_ttl += (double)(when-now) / (db->expireSize()+1);    // add the new entry
     db->last_expire_set = now;
 
     /* Update the expire set */
-    const char *szSubKey = (subkey != nullptr) ? szFromObj(subkey) : nullptr;
+    db->m_persistentData.setExpire(key, subkey, when);
-    if (((robj*)dictGetVal(kde))->FExpires()) {
-        auto itr = db->setexpire->find((sds)dictGetKey(kde));
-        serverAssert(itr != db->setexpire->end());
-        expireEntry eNew(std::move(*itr));
-        eNew.update(szSubKey, when);
-        db->setexpire->erase(itr);
-        db->setexpire->insert(eNew);
-    }
-    else
-    {
-        expireEntry e((sds)dictGetKey(kde), szSubKey, when);
-        ((robj*)dictGetVal(kde))->SetFExpires(true);
-        db->setexpire->insert(e);
-    }
 
     int writable_slave = listLength(g_pserver->masters) && g_pserver->repl_slave_ro == 0;
     if (c && writable_slave && !(c->flags & CLIENT_MASTER))
@@ -1294,26 +1260,24 @@ void setExpire(client *c, redisDb *db, robj *key, robj *subkey, long long when)
 
 void setExpire(client *c, redisDb *db, robj *key, expireEntry &&e)
 {
-    dictEntry *kde;
-
     serverAssert(GlobalLocksAcquired());
 
     /* Reuse the sds from the main dict in the expire dict */
-    kde = dictFind(db->pdict,ptrFromObj(key));
+    auto kde = db->find(key);
     serverAssertWithInfo(NULL,key,kde != NULL);
 
-    if (((robj*)dictGetVal(kde))->getrefcount(std::memory_order_relaxed) == OBJ_SHARED_REFCOUNT)
+    if (kde.val()->getrefcount(std::memory_order_relaxed) == OBJ_SHARED_REFCOUNT)
     {
         // shared objects cannot have the expire bit set, create a real object
-        dictSetVal(db->pdict, kde, dupStringObject((robj*)dictGetVal(kde)));
+        db->m_persistentData.updateValue(kde, dupStringObject(kde.val()));
     }
 
-    if (((robj*)dictGetVal(kde))->FExpires())
+    if (kde.val()->FExpires())
         removeExpire(db, key);
 
-    e.setKeyUnsafe((sds)dictGetKey(kde));
+    e.setKeyUnsafe(kde.key());
-    db->setexpire->insert(e);
+    db->m_persistentData.setExpire(std::move(e));
-    ((robj*)dictGetVal(kde))->SetFExpires(true);
+    kde.val()->SetFExpires(true);
 
 
     int writable_slave = listLength(g_pserver->masters) && g_pserver->repl_slave_ro == 0;
@@ -1323,19 +1287,24 @@ void setExpire(client *c, redisDb *db, robj *key, expireEntry &&e)
 
 /* Return the expire time of the specified key, or null if no expire
  * is associated with this key (i.e. the key is non volatile) */
-expireEntry *getExpire(redisDb *db, robj_roptr key) {
+expireEntry *redisDb::getExpire(robj_roptr key) {
     /* No expire? return ASAP */
-    if (db->setexpire->size() == 0)
+    if (expireSize() == 0)
         return nullptr;
 
-    auto pair = db->lookup_tuple(key);
+    auto itr = find(key);
-    if (pair.first == nullptr)
+    if (itr == nullptr)
         return nullptr;
-    if (!pair.second->FExpires())
+    if (!itr.val()->FExpires())
         return nullptr;
 
-    auto itr = db->setexpire->find(pair.first);
+    auto itrExpire = m_persistentData.findExpire(itr.key());
-    return itr.operator->();
+    return itrExpire.operator->();
+}
+
+expireEntry *getExpire(redisDb *db, robj_roptr key)
+{
+    return db->getExpire(key);
 }
 
 /* Propagate expires into slaves and the AOF file.
@@ -1798,11 +1767,18 @@ unsigned int countKeysInSlot(unsigned int hashslot) {
     return g_pserver->cluster->slots_keys_count[hashslot];
 }
 
+void redisDbPersistentData::initialize()
+{
+    m_pdict = dictCreate(&dbDictType,NULL);
+    m_setexpire = new(MALLOC_LOCAL) expireset();
+    m_fAllChanged = false;
+    m_fTrackingChanges = false;
+}
+
 void redisDb::initialize(int id)
 {
-    this->pdict = dictCreate(&dbDictType,NULL);
+    m_persistentData.initialize();
-    this->setexpire = new(MALLOC_LOCAL) expireset();
+    this->expireitr = m_persistentData.setexpireUnsafe()->end();
-    this->expireitr = this->setexpire->end();
     this->blocking_keys = dictCreate(&keylistDictType,NULL);
     this->ready_keys = dictCreate(&objectKeyPointerValueDictType,NULL);
     this->watched_keys = dictCreate(&keylistDictType,NULL);
@@ -1811,3 +1787,96 @@ void redisDb::initialize(int id)
     this->last_expire_set = 0;
     this->defrag_later = listCreate();
 }
+
+bool redisDbPersistentData::insert(char *key, robj *o)
+{
+    int res = dictAdd(m_pdict, key, o);
+    if (res == DICT_OK)
+        trackkey(key);
+    return (res == DICT_OK);
+}
+
+void redisDbPersistentData::tryResize()
+{
+    if (htNeedsResize(m_pdict))
+        dictResize(m_pdict);
+}
+
+size_t redisDb::clear(bool fAsync, void(callback)(void*))
+{
+    size_t removed = m_persistentData.size();
+    if (fAsync) {
+        m_persistentData.emptyDbAsync();
+    } else {
+        m_persistentData.clear(callback);
+    }
+    expireitr = m_persistentData.setexpireUnsafe()->end();
+    return removed;
+}
+
+void redisDbPersistentData::clear(void(callback)(void*))
+{
+    dictEmpty(m_pdict,callback);
+    if (m_fTrackingChanges)
+        m_fAllChanged = true;
+    delete m_setexpire;
+    m_setexpire = new (MALLOC_LOCAL) expireset();
+}
+
+/* static */ void redisDbPersistentData::swap(redisDbPersistentData *db1, redisDbPersistentData *db2)
+{
+    redisDbPersistentData aux = *db1;
+    db1->m_pdict = db2->m_pdict;
+    db1->m_fTrackingChanges = db2->m_fTrackingChanges;
+    db1->m_fAllChanged = db2->m_fAllChanged;
+    db1->m_setexpire = db2->m_setexpire;
+
+    db2->m_pdict = aux.m_pdict;
+    db2->m_fTrackingChanges = aux.m_fTrackingChanges;
+    db2->m_fAllChanged = aux.m_fAllChanged;
+    db2->m_setexpire = aux.m_setexpire;
+}
+
+void redisDbPersistentData::setExpire(robj *key, robj *subkey, long long when)
+{
+    /* Reuse the sds from the main dict in the expire dict */
+    dictEntry *kde = dictFind(m_pdict,ptrFromObj(key));
+    serverAssertWithInfo(NULL,key,kde != NULL);
+
+    if (((robj*)dictGetVal(kde))->getrefcount(std::memory_order_relaxed) == OBJ_SHARED_REFCOUNT)
+    {
+        // shared objects cannot have the expire bit set, create a real object
+        dictSetVal(m_pdict, kde, dupStringObject((robj*)dictGetVal(kde)));
+    }
+
+    const char *szSubKey = (subkey != nullptr) ? szFromObj(subkey) : nullptr;
+    if (((robj*)dictGetVal(kde))->FExpires()) {
+        auto itr = m_setexpire->find((sds)dictGetKey(kde));
+        serverAssert(itr != m_setexpire->end());
+        expireEntry eNew(std::move(*itr));
+        eNew.update(szSubKey, when);
+        m_setexpire->erase(itr);
+        m_setexpire->insert(eNew);
+    }
+    else
+    {
+        expireEntry e((sds)dictGetKey(kde), szSubKey, when);
+        ((robj*)dictGetVal(kde))->SetFExpires(true);
+        m_setexpire->insert(e);
+    }
+}
+
+void redisDbPersistentData::setExpire(expireEntry &&e)
+{
+    m_setexpire->insert(e);
+}
+
+bool redisDb::FKeyExpires(const char *key)
+{
+    return m_persistentData.setexpireUnsafe()->find(key) != m_persistentData.setexpireUnsafe()->end();
+}
+
+void redisDbPersistentData::updateValue(dict_iter itr, robj *val)
+{
+    dictSetVal(m_pdict, itr.de, val);
+}

src/debug.cpp

@@ -439,9 +439,9 @@ NULL
             strenc, rdbSavedObjectLen(val),
             val->lru, estimateObjectIdleTime(val)/1000, extra);
     } else if (!strcasecmp(szFromObj(c->argv[1]),"sdslen") && c->argc == 3) {
-        auto pair = c->db->lookup_tuple(c->argv[2]);
+        auto itr = c->db->find(c->argv[2]);
-        robj *val = pair.second;
+        robj *val = itr.val();
-        const char *key = pair.first;
+        const char *key = itr.key();
 
         if (val == NULL) {
             addReply(c,shared.nokeyerr);
@@ -636,7 +636,7 @@ NULL
         stats = sdscat(stats,buf);
 
         stats = sdscatprintf(stats,"[Expires set]\n");
-        g_pserver->db[dbid].setexpire->getstats(buf, sizeof(buf));
+        g_pserver->db[dbid].getExpireStats(buf, sizeof(buf));
         stats = sdscat(stats, buf);
 
         addReplyBulkSds(c,stats);

src/defrag.cpp

@@ -781,8 +781,8 @@ long defragKey(redisDb *db, dictEntry *de) {
     newsds = activeDefragSds(keysds);
     if (newsds)
         defragged++, de->key = newsds;
-    if (!db->setexpire->empty()) {
+    if (!db->setexpire()->empty()) {
-        replaceSateliteOSetKeyPtr(*db->setexpire, keysds, newsds);
+        replaceSateliteOSetKeyPtr(*const_cast<expireset*>(db->setexpire()), keysds, newsds);
     }
 
     /* Try to defrag robj and / or string value. */
@@ -1111,7 +1111,7 @@ void activeDefragCycle(void) {
                 break; /* this will exit the function and we'll continue on the next cycle */
             }
 
-            cursor = dictScan(db->pdict, cursor, defragScanCallback, defragDictBucketCallback, db);
+            cursor = dictScan(db->dictUnsafe(), cursor, defragScanCallback, defragDictBucketCallback, db);
 
             /* Once in 16 scan iterations, 512 pointer reallocations. or 64 keys
              * (if we have a lot of pointers in one hash bucket or rehasing),

src/evict.cpp

@@ -256,13 +256,13 @@ void evictionPoolPopulate(int dbid, redisDb *db, expireset *setexpire, struct ev
 {
     if (setexpire != nullptr)
     {
-        visitFunctor visitor { dbid, db->pdict, pool, 0 };
+        visitFunctor visitor { dbid, db->m_persistentData.dictUnsafe(), pool, 0 };
         setexpire->random_visit(visitor);
     }
     else
     {
         dictEntry **samples = (dictEntry**)alloca(g_pserver->maxmemory_samples * sizeof(dictEntry*));
-        int count = dictGetSomeKeys(db->pdict,samples,g_pserver->maxmemory_samples);
+        int count = dictGetSomeKeys(db->m_persistentData.dictUnsafe(),samples,g_pserver->maxmemory_samples);
         for (int j = 0; j < count; j++) {
             robj *o = (robj*)dictGetVal(samples[j]);
             processEvictionCandidate(dbid, (sds)dictGetKey(samples[j]), o, nullptr, pool);
@@ -511,9 +511,9 @@ int freeMemoryIfNeeded(void) {
                     }
                     else
                     {
-                        keys = db->setexpire->size();
+                        keys = db->expireSize();
                         if (keys != 0)
-                            evictionPoolPopulate(i, db, db->setexpire, pool);
+                            evictionPoolPopulate(i, db, db->m_persistentData.setexpireUnsafe(), pool);
                         total_keys += keys;
                     }
                 }
@@ -525,9 +525,9 @@ int freeMemoryIfNeeded(void) {
                     bestdbid = pool[k].dbid;
                     sds key = nullptr;
 
-                    auto pair = g_pserver->db[pool[k].dbid].lookup_tuple(pool[k].key);
+                    auto itr = g_pserver->db[pool[k].dbid].find(pool[k].key);
-                    if (pair.first != nullptr && (g_pserver->maxmemory_policy & MAXMEMORY_FLAG_ALLKEYS || pair.second->FExpires()))
+                    if (itr != nullptr && (g_pserver->maxmemory_policy & MAXMEMORY_FLAG_ALLKEYS || itr.val()->FExpires()))
-                        key = (sds)pair.first;
+                        key = itr.key();
 
                     /* Remove the entry from the pool. */
                     if (pool[k].key != pool[k].cached)
@@ -560,17 +560,17 @@ int freeMemoryIfNeeded(void) {
                 if (g_pserver->maxmemory_policy == MAXMEMORY_ALLKEYS_RANDOM)
                 {
                     if (db->size() != 0) {
-                        auto pair = db->random();
+                        auto itr = db->random();
-                        bestkey = (sds)pair.first;
+                        bestkey = itr.key();
                         bestdbid = j;
                         break;
                     }
                 }
                 else
                 {
-                    if (!db->setexpire->empty())
+                    if (db->expireSize())
                     {
-                        bestkey = (sds)db->setexpire->random_value().key();
+                        bestkey = (sds)db->random_expire().key();
                         bestdbid = j;
                         break;
                     }

src/expire.cpp

@@ -248,7 +248,7 @@ void activeExpireCycle(int type) {
         now = mstime();
 
         /* If there is nothing to expire try next DB ASAP. */
-        if (db->setexpire->empty())
+        if (db->m_persistentData.setexpireUnsafe()->empty())
         {
             db->avg_ttl = 0;
             db->last_expire_set = now;
@@ -258,7 +258,7 @@ void activeExpireCycle(int type) {
         size_t expired = 0;
         size_t tried = 0;
         long long check = ACTIVE_EXPIRE_CYCLE_FAST_DURATION;    // assume a check is roughly 1us.  It isn't but good enough
-        db->expireitr = db->setexpire->enumerate(db->expireitr, now, [&](expireEntry &e) __attribute__((always_inline)) {
+        db->expireitr = db->m_persistentData.setexpireUnsafe()->enumerate(db->expireitr, now, [&](expireEntry &e) __attribute__((always_inline)) {
             if (e.when() < now)
             {
                 activeExpireCycleExpire(db, e, now);
@@ -358,16 +358,16 @@ void expireSlaveKeys(void) {
                 redisDb *db = g_pserver->db+dbid;
 
                 // the expire is hashed based on the key pointer, so we need the point in the main db
-                auto pairMain = db->lookup_tuple(keyname);
+                auto itrDB = db->find(keyname);
-                auto itr = db->setexpire->end();
+                auto itrExpire = db->m_persistentData.setexpireUnsafe()->end();
-                if (pairMain.first != nullptr)
+                if (itrDB != nullptr)
-                    itr = db->setexpire->find((sds)pairMain.first);
+                    itrExpire = db->m_persistentData.setexpireUnsafe()->find(itrDB.key());
                 int expired = 0;
 
-                if (itr != db->setexpire->end())
+                if (itrExpire != db->m_persistentData.setexpireUnsafe()->end())
                 {
-                    if (itr->when() < start) {
+                    if (itrExpire->when() < start) {
-                        activeExpireCycleExpire(g_pserver->db+dbid,*itr,start);
+                        activeExpireCycleExpire(g_pserver->db+dbid,*itrExpire,start);
                         expired = 1;
                     }
                 }
@@ -376,7 +376,7 @@ void expireSlaveKeys(void) {
                  * corresponding bit in the new bitmap we set as value.
                  * At the end of the loop if the bitmap is zero, it means we
                  * no longer need to keep track of this key. */
-                if (itr != db->setexpire->end() && !expired) {
+                if (itrExpire != db->m_persistentData.setexpireUnsafe()->end() && !expired) {
                     noexpire++;
                     new_dbids |= (uint64_t)1 << dbid;
                 }

src/lazyfree.cpp

@@ -51,18 +51,18 @@ size_t lazyfreeGetFreeEffort(robj *obj) {
  * a lazy free list instead of being freed synchronously. The lazy free list
  * will be reclaimed in a different bio.c thread. */
 #define LAZYFREE_THRESHOLD 64
-int dbAsyncDelete(redisDb *db, robj *key) {
+bool redisDbPersistentData::asyncDelete(robj *key) {
     /* If the value is composed of a few allocations, to free in a lazy way
      * is actually just slower... So under a certain limit we just free
      * the object synchronously. */
-    dictEntry *de = dictUnlink(db->pdict,ptrFromObj(key));
+    dictEntry *de = dictUnlink(m_pdict,ptrFromObj(key));
     if (de) {
         robj *val = (robj*)dictGetVal(de);
         if (val->FExpires())
         {
             /* Deleting an entry from the expires dict will not free the sds of
              * the key, because it is shared with the main dictionary. */
-            removeExpireCore(db,key,de);
+            removeExpire(key,dict_iter(de));
         }
 
         size_t free_effort = lazyfreeGetFreeEffort(val);
@@ -78,21 +78,25 @@ int dbAsyncDelete(redisDb *db, robj *key) {
         if (free_effort > LAZYFREE_THRESHOLD && val->getrefcount(std::memory_order_relaxed) == 1) {
             atomicIncr(lazyfree_objects,1);
             bioCreateBackgroundJob(BIO_LAZY_FREE,val,NULL,NULL);
-            dictSetVal(db->pdict,de,NULL);
+            dictSetVal(m_pdict,de,NULL);
         }
     }
 
     /* Release the key-val pair, or just the key if we set the val
      * field to NULL in order to lazy free it later. */
     if (de) {
-        dictFreeUnlinkedEntry(db->pdict,de);
+        dictFreeUnlinkedEntry(m_pdict,de);
         if (g_pserver->cluster_enabled) slotToKeyDel(key);
-        return 1;
+        return true;
     } else {
-        return 0;
+        return false;
     }
 }
 
+int dbAsyncDelete(redisDb *db, robj *key) {
+    return db->m_persistentData.asyncDelete(key);
+}
+
 /* Free an object, if the object is huge enough, free it in async way. */
 void freeObjAsync(robj *o) {
     size_t free_effort = lazyfreeGetFreeEffort(o);
@@ -107,12 +111,13 @@ void freeObjAsync(robj *o) {
 /* Empty a Redis DB asynchronously. What the function does actually is to
  * create a new empty set of hash tables and scheduling the old ones for
  * lazy freeing. */
-void emptyDbAsync(redisDb *db) {
+void redisDbPersistentData::emptyDbAsync() {
-    dict *oldht1 = db->pdict;
+    dict *oldht1 = m_pdict;
-    auto *set = db->setexpire;
+    auto *set = m_setexpire;
-    db->setexpire = new (MALLOC_LOCAL) expireset();
+    m_setexpire = new (MALLOC_LOCAL) expireset();
-    db->expireitr = db->setexpire->end();
+    m_pdict = dictCreate(&dbDictType,NULL);
-    db->pdict = dictCreate(&dbDictType,NULL);
+    if (m_fTrackingChanges)
+        m_fAllChanged = true;
     atomicIncr(lazyfree_objects,dictSize(oldht1));
     bioCreateBackgroundJob(BIO_LAZY_FREE,NULL,oldht1,set);
 }

src/object.cpp

@@ -1067,7 +1067,7 @@ struct redisMemOverhead *getMemoryOverheadData(void) {
         mh->db[mh->num_dbs].overhead_ht_main = mem;
         mem_total+=mem;
 
-        mem = db->setexpire->bytes_used();
+        mem = db->setexpire()->bytes_used();
         mh->db[mh->num_dbs].overhead_ht_expires = mem;
         mem_total+=mem;
 
@@ -1339,13 +1339,13 @@ NULL
             }
         }
 
-        auto pair = c->db->lookup_tuple(c->argv[2]);
+        auto itr = c->db->find(c->argv[2]);
-        if (pair.first == NULL) {
+        if (itr == nullptr) {
             addReplyNull(c, shared.nullbulk);
             return;
         }
-        size_t usage = objectComputeSize(pair.second,samples);
+        size_t usage = objectComputeSize(itr.val(),samples);
-        usage += sdsAllocSize((sds)pair.first);
+        usage += sdsAllocSize(itr.key());
         usage += sizeof(dictEntry);
         addReplyLongLong(c,usage);
     } else if (!strcasecmp(szFromObj(c->argv[1]),"stats") && c->argc == 2) {

src/rdb.cpp

@@ -1170,7 +1170,7 @@ int rdbSaveRio(rio *rdb, int *error, int flags, rdbSaveInfo *rsi) {
          * these sizes are just hints to resize the hash tables. */
         uint64_t db_size, expires_size;
         db_size = db->size();
-        expires_size = db->setexpire->size();
+        expires_size = db->expireSize();
         if (rdbSaveType(rdb,RDB_OPCODE_RESIZEDB) == -1) goto werr;
         if (rdbSaveLen(rdb,db_size) == -1) goto werr;
         if (rdbSaveLen(rdb,expires_size) == -1) goto werr;
@@ -1187,7 +1187,7 @@ int rdbSaveRio(rio *rdb, int *error, int flags, rdbSaveInfo *rsi) {
         });
         if (!fSavedAll)
             goto werr;
-        serverAssert(ckeysExpired == db->setexpire->size());
+        serverAssert(ckeysExpired == db->expireSize());
     }
 
     /* If we are storing the replication information on disk, persist

src/server.cpp

@@ -1431,8 +1431,7 @@ int htNeedsResize(dict *dict) {
 /* If the percentage of used slots in the HT reaches HASHTABLE_MIN_FILL
  * we resize the hash table to save memory */
 void tryResizeHashTables(int dbid) {
-    if (htNeedsResize(g_pserver->db[dbid].pdict))
+    g_pserver->db[dbid].tryResize();
-        dictResize(g_pserver->db[dbid].pdict);
 }
 
 /* Our hash table implementation performs rehashing incrementally while
@@ -1442,10 +1441,10 @@ void tryResizeHashTables(int dbid) {
  *
  * The function returns 1 if some rehashing was performed, otherwise 0
  * is returned. */
-int incrementallyRehash(int dbid) {
+int redisDbPersistentData::incrementallyRehash() {
     /* Keys dictionary */
-    if (dictIsRehashing(g_pserver->db[dbid].pdict)) {
+    if (dictIsRehashing(m_pdict)) {
-        dictRehashMilliseconds(g_pserver->db[dbid].pdict,1);
+        dictRehashMilliseconds(m_pdict,1);
         return 1; /* already used our millisecond for this loop... */
     }
     return 0;
@@ -1726,7 +1725,7 @@ void databasesCron(void) {
         /* Rehash */
         if (g_pserver->activerehashing) {
             for (j = 0; j < dbs_per_call; j++) {
-                int work_done = incrementallyRehash(rehash_db);
+                int work_done = g_pserver->db[rehash_db].incrementallyRehash();
                 if (work_done) {
                     /* If the function did some work, stop here, we'll do
                      * more at the next cron loop. */
@@ -1887,7 +1886,7 @@ int serverCron(struct aeEventLoop *eventLoop, long long id, void *clientData) {
 
             size = g_pserver->db[j].slots();
             used = g_pserver->db[j].size();
-            vkeys = g_pserver->db[j].setexpire->size();
+            vkeys = g_pserver->db[j].expireSize();
             if (used || vkeys) {
                 serverLog(LL_VERBOSE,"DB %d: %lld keys (%lld volatile) in %lld slots HT.",j,used,vkeys,size);
                 /* dictPrintStats(g_pserver->dict); */
@@ -4567,7 +4566,7 @@ sds genRedisInfoString(const char *section) {
             long long keys, vkeys;
 
             keys = g_pserver->db[j].size();
-            vkeys = g_pserver->db[j].setexpire->size();
+            vkeys = g_pserver->db[j].expireSize();
 
             // Adjust TTL by the current time
             g_pserver->db[j].avg_ttl -= (g_pserver->mstime - g_pserver->db[j].last_expire_set);

src/server.h

@@ -54,6 +54,7 @@
 #include <vector>
 #include <algorithm>
 #include <memory>
+#include <set>
 #ifdef __cplusplus
 extern "C" {
 #include <lua.h>
@@ -1015,22 +1016,123 @@ typedef struct clientReplyBlock {
 #endif
 } clientReplyBlock;
 
+struct dictEntry;
+class dict_const_iter
+{
+    friend class redisDb;
+    friend class redisDbPersistentData;
+protected:
+    dictEntry *de;
+public:
+    explicit dict_const_iter(dictEntry *de)
+        : de(de)
+    {}
+
+    const char *key() const { return de ? (const char*)dictGetKey(de) : nullptr; }
+    robj_roptr val() const { return de ? (robj*)dictGetVal(de) : nullptr; }
+    const robj* operator->() const { return de ? (robj*)dictGetVal(de) : nullptr; }
+    operator robj_roptr() const { return de ? (robj*)dictGetVal(de) : nullptr; }
+
+    bool operator==(std::nullptr_t) const { return de == nullptr; }
+    bool operator!=(std::nullptr_t) const { return de != nullptr; }
+    bool operator==(const dict_const_iter &other) { return de == other.de; }
+};
+class dict_iter : public dict_const_iter
+{
+public:
+    explicit dict_iter(dictEntry *de)
+        : dict_const_iter(de)
+    {}
+    sds key() { return de ? (sds)dictGetKey(de) : nullptr; }
+    robj *val() { return de ? (robj*)dictGetVal(de) : nullptr; }
+    robj *operator->() { return de ? (robj*)dictGetVal(de) : nullptr; }
+    operator robj*() const { return de ? (robj*)dictGetVal(de) : nullptr; }
+};
+
+class redisDbPersistentData
+{
+public:
+    static void swap(redisDbPersistentData *db1, redisDbPersistentData *db2);
+
+    size_t slots() const { return dictSlots(m_pdict); }
+    size_t size() const { return dictSize(m_pdict); }
+    void expand(uint64_t slots) { dictExpand(m_pdict, slots); }
+    
+    void trackkey(robj_roptr o)
+    {
+        trackkey(szFromObj(o));
+    }
+
+    void trackkey(const char *key)
+    {
+        if (m_fTrackingChanges)
+            m_setchanged.insert(key);
+    }
+
+    dict_iter find(const char *key) 
+    {
+        dictEntry *de = dictFind(m_pdict, key);
+        return dict_iter(de);
+    }
+
+    dict_iter random()
+    {
+        dictEntry *de = dictGetRandomKey(m_pdict);
+        return dict_iter(de);
+    }
+
+    const expireEntry &random_expire()
+    {
+        return m_setexpire->random_value();
+    }
+
+    auto findExpire(const char *key)
+    {
+        return m_setexpire->find(key);
+    }
+
+    void getStats(char *buf, size_t bufsize) { dictGetStats(buf, bufsize, m_pdict); }
+    void getExpireStats(char *buf, size_t bufsize) { m_setexpire->getstats(buf, bufsize); }
+
+    bool insert(char *k, robj *o);
+    void tryResize();
+    int incrementallyRehash();
+    void updateValue(dict_iter itr, robj *val);
+    bool syncDelete(robj *key);
+    bool asyncDelete(robj *key);
+    size_t expireSize() const { return m_setexpire->size(); }
+    int removeExpire(robj *key, dict_iter itr);
+    void clear(void(callback)(void*));
+    void emptyDbAsync();
+    bool iterate(std::function<bool(const char*, robj*)> &fn);
+    void setExpire(robj *key, robj *subkey, long long when);
+    void setExpire(expireEntry &&e);
+    void initialize();
+
+    dict *dictUnsafe() { return m_pdict; }
+    expireset *setexpireUnsafe() { return m_setexpire; }
+    const expireset *setexpire() { return m_setexpire; }
+
+private:
+    // Keyspace
+    dict *m_pdict;                 /* The keyspace for this DB */
+    bool m_fTrackingChanges = false;
+    bool m_fAllChanged = false;
+    std::set<std::string> m_setchanged;
+
+    // Expire
+    expireset *m_setexpire;
+};
+
 /* Redis database representation. There are multiple databases identified
  * by integers from 0 (the default database) up to the max configured
  * database. The database number is the 'id' field in the structure. */
 typedef struct redisDb {
     // Legacy C API, Do not add more
     friend void tryResizeHashTables(int);
-    friend int incrementallyRehash(int);
-    friend int dbAddCore(redisDb *db, robj *key, robj *val);
-    friend void dbOverwriteCore(redisDb *db, dictEntry *de, robj *key, robj *val, bool fUpdateMvcc, bool fRemoveExpire);
-    friend void dbOverwrite(redisDb *db, robj *key, robj *val);
-    friend int dbMerge(redisDb *db, robj *key, robj *val, int fReplace);
-    friend void setKey(redisDb *db, robj *key, robj *val);
     friend int dbSyncDelete(redisDb *db, robj *key);
     friend int dbAsyncDelete(redisDb *db, robj *key);
     friend long long emptyDb(int dbnum, int flags, void(callback)(void*));
-    friend void emptyDbAsync(redisDb *db);
     friend void scanGenericCommand(struct client *c, robj_roptr o, unsigned long cursor);
     friend int dbSwapDatabases(int id1, int id2);
     friend int removeExpire(redisDb *db, robj *key);
@@ -1038,58 +1140,64 @@ typedef struct redisDb {
     friend void setExpire(client *c, redisDb *db, robj *key, expireEntry &&e);
     friend void evictionPoolPopulate(int dbid, redisDb *db, expireset *setexpire, struct evictionPoolEntry *pool);
     friend void activeDefragCycle(void);
+    friend int freeMemoryIfNeeded(void);
+    friend void activeExpireCycle(int);
+    friend void expireSlaveKeys(void);
+
+    typedef ::dict_const_iter const_iter;
+    typedef ::dict_iter iter;
 
     redisDb()
         : expireitr(nullptr)
-    {};
+    {}
 
     void initialize(int id);
 
-    size_t slots() const { return dictSlots(pdict); }
+    size_t slots() const { return m_persistentData.slots(); }
-    size_t size() const { return dictSize(pdict); }
+    size_t size() const { return m_persistentData.size(); }
-    void expand(uint64_t slots) { dictExpand(pdict, slots); }
+    size_t expireSize() const { return m_persistentData.expireSize(); }
+    void expand(uint64_t slots) { m_persistentData.expand(slots); }
+    void tryResize() { m_persistentData.tryResize(); }
+    const expireset *setexpire() { return m_persistentData.setexpire(); }
     
-    robj *find(robj_roptr key)
+    iter find(robj_roptr key)
     {
         return find(szFromObj(key));
     }
-    robj *find(const char *key) 
+    iter find(const char *key) 
     {
-        dictEntry *de = dictFind(pdict, key);
+        return m_persistentData.find(key);
-        if (de != nullptr)
-            return (robj*)dictGetVal(de);
-        return nullptr;
     }
 
-    std::pair<const char*,robj*> lookup_tuple(robj_roptr key)
+    iter random()
     {
-        return lookup_tuple(szFromObj(key));
+        return m_persistentData.random();
-    }
-    std::pair<const char*,robj*> lookup_tuple(const char *key)
-    {
-        dictEntry *de = dictFind(pdict, key);
-        if (de != nullptr)
-            return std::make_pair<const char*,robj*>((const char*)dictGetKey(de), (robj*)dictGetVal(de));
-        return std::make_pair<const char*,robj*>(nullptr, nullptr);
     }
 
-    std::pair<const char*,robj*> random()
+    const expireEntry &random_expire()
     {
-        dictEntry *de = dictGetRandomKey(pdict);
+        return m_persistentData.random_expire();
-        if (de != nullptr)
-            return std::make_pair<const char*,robj*>((const char*)dictGetKey(de), (robj*)dictGetVal(de));
-        return std::make_pair<const char*,robj*>(nullptr, nullptr);
     }
 
-    bool iterate(std::function<bool(const char*, robj*)> fn);
+    const_iter end() { return const_iter(nullptr); }
-    void getStats(char *buf, size_t bufsize) { dictGetStats(buf, bufsize, pdict); }
 
+    bool iterate(std::function<bool(const char*, robj*)> fn) { return m_persistentData.iterate(fn); }
+    void getStats(char *buf, size_t bufsize) { m_persistentData.getStats(buf, bufsize); }
+    void getExpireStats(char *buf, size_t bufsize) { m_persistentData.getExpireStats(buf, bufsize); }
+
+    bool insert(char *key, robj *o) { return m_persistentData.insert(key, o); }
+    void dbOverwriteCore(redisDb::iter itr, robj *key, robj *val, bool fUpdateMvcc, bool fRemoveExpire);
+
+    int incrementallyRehash() { return m_persistentData.incrementallyRehash(); };
+
+    bool FKeyExpires(const char *key);
+    size_t clear(bool fAsync, void(callback)(void*));
+    dict *dictUnsafe() { return m_persistentData.dictUnsafe(); }
+    expireEntry *getExpire(robj_roptr key);
 private:
-    dict *pdict;                 /* The keyspace for this DB */
+    redisDbPersistentData m_persistentData;
 public:
-    expireset *setexpire;
     expireset::setiter expireitr;
-
     dict *blocking_keys;        /* Keys with clients waiting for data (BLPOP)*/
     dict *ready_keys;           /* Blocked keys that received a PUSH */
     dict *watched_keys;         /* WATCHED keys for MULTI/EXEC CAS */
@@ -2476,7 +2584,6 @@ int rewriteConfig(char *path);
 
 /* db.c -- Keyspace access API */
 int removeExpire(redisDb *db, robj *key);
-int removeExpireCore(redisDb *db, robj *key, dictEntry *de);
 void propagateExpire(redisDb *db, robj *key, int lazy);
 int expireIfNeeded(redisDb *db, robj *key);
 expireEntry *getExpire(redisDb *db, robj_roptr key);
@@ -2521,7 +2628,6 @@ void slotToKeyAdd(robj *key);
 void slotToKeyDel(robj *key);
 void slotToKeyFlush(void);
 int dbAsyncDelete(redisDb *db, robj *key);
-void emptyDbAsync(redisDb *db);
 void slotToKeyFlushAsync(void);
 size_t lazyfreeGetPendingObjectsCount(void);
 void freeObjAsync(robj *o);