changes following code review

Signed-off-by: xbasel <[email protected]>

Author: xbasel

src/aof.c

@@ -2210,7 +2210,7 @@ int rewriteAppendOnlyFileRio(rio *aof) {
 
     for (j = 0; j < server.dbnum; j++) {
         char selectcmd[] = "*2\r\n$6\r\nSELECT\r\n";
-        if (databaseEmpty(j)) continue;
+        if (dbHasNoKeys(j)) continue;
         serverDb *db = server.db[j];
 
         /* SELECT the new DB */

src/cluster_legacy.c

@@ -5711,7 +5711,7 @@ int verifyClusterConfigWithData(void) {
 
     /* Make sure we only have keys in DB0. */
     for (j = 1; j < server.dbnum; j++) {
-        if (!databaseEmpty(j)) return C_ERR;
+        if (!dbHasNoKeys(j)) return C_ERR;
     }
 
     /* Check that all the slots we see populated memory have a corresponding
@@ -6828,7 +6828,7 @@ int clusterCommandSpecial(client *c) {
         }
     } else if (!strcasecmp(c->argv[1]->ptr, "flushslots") && c->argc == 2) {
         /* CLUSTER FLUSHSLOTS */
-        if (!databaseEmpty(0)) {
+        if (!dbHasNoKeys(0)) {
             addReplyError(c, "DB must be empty to perform CLUSTER FLUSHSLOTS.");
             return 1;
         }
@@ -6969,7 +6969,7 @@ int clusterCommandSpecial(client *c) {
         /* If the instance is currently a primary, it should have no assigned
          * slots nor keys to accept to replicate some other node.
          * Replicas can switch to another primary without issues. */
-        if (clusterNodeIsPrimary(myself) && (myself->numslots != 0 || !databaseEmpty(0))) {
+        if (clusterNodeIsPrimary(myself) && (myself->numslots != 0 || !dbHasNoKeys(0))) {
             addReplyError(c, "To set a master the node must be empty and "
                              "without assigned slots.");
             return 1;

src/db.c

@@ -679,16 +679,15 @@ void discardTempDb(serverDb **tempDb) {
 
 int selectDb(client *c, int id) {
     if (id < 0 || id >= server.dbnum) return C_ERR;
-    initDatabase(id);
-    c->db = server.db[id];
+    c->db = createDatabaseIfNeeded(id);
     return C_OK;
 }
 
 long long dbTotalServerKeyCount(void) {
     long long total = 0;
     int j;
     for (j = 0; j < server.dbnum; j++) {
-        if (databaseEmpty(j)) continue;
+        if (dbHasNoKeys(j)) continue;
         total += kvstoreSize(server.db[j]->keys);
     }
     return total;
@@ -1641,10 +1640,9 @@ void scanDatabaseForDeletedKeys(serverDb *emptied, serverDb *replaced_with) {
 int dbSwapDatabases(int id1, int id2) {
     if (id1 < 0 || id1 >= server.dbnum || id2 < 0 || id2 >= server.dbnum) return C_ERR;
     if (id1 == id2) return C_OK;
-    initDatabase(id1);
-    initDatabase(id2);
-    serverDb aux = *server.db[id1];
-    serverDb *db1 = server.db[id1], *db2 = server.db[id2];
+    serverDb *db1 = createDatabaseIfNeeded(id1);
+    serverDb *db2 = createDatabaseIfNeeded(id2);
+    serverDb aux = *db1;
 
     /* Swapdb should make transaction fail if there is any
      * client watching keys */

src/defrag.c

@@ -1273,7 +1273,7 @@ static void beginDefragCycle(void) {
     defrag.remaining_stages = listCreate();
 
     for (int dbid = 0; dbid < server.dbnum; dbid++) {
-        if (databaseEmpty(dbid)) continue;
+        if (dbHasNoKeys(dbid)) continue;
         addDefragStage(defragStageDbKeys, (void *)(uintptr_t)dbid, NULL);
         addDefragStage(defragStageExpiresKvstore, (void *)(uintptr_t)dbid, NULL);
     }

src/replication.c

@@ -2667,7 +2667,7 @@ int sendCurrentOffsetToReplica(client *replica) {
     char buf[128];
     int buflen;
     buflen = snprintf(buf, sizeof(buf), "$ENDOFF:%lld %s %d %llu\r\n", server.primary_repl_offset, server.replid,
-                      server.db[0]->id, (long long unsigned int)replica->id); // TODO xbasel , why is it index 0 ?
+                      server.db[0]->id, (long long unsigned int)replica->id);
     dualChannelServerLog(LL_NOTICE, "Sending to replica %s RDB end offset %lld and client-id %llu",
                          replicationGetReplicaName(replica), server.primary_repl_offset,
                          (long long unsigned int)replica->id);

src/server.c

@@ -2722,26 +2722,10 @@ void makeThreadKillable(void) {
 }
 
 /* Return non-zero if the database is empty  */
-int databaseEmpty(int id) {
-    return id < 0 || id >= server.dbnum || !server.db[id] || kvstoreSize(server.db[id]->keys) == 0;
-}
-
-// /* Initialize temporary db on replica for use during diskless replication. */
-// serverDb *initTempDb(int id) {
-//     int slot_count_bits = 0;
-//     int flags = KVSTORE_ALLOCATE_HASHTABLES_ON_DEMAND;
-//     if (server.cluster_enabled) {
-//         slot_count_bits = CLUSTER_SLOT_MASK_BITS;
-//         flags |= KVSTORE_FREE_EMPTY_HASHTABLES;
-//     }
-//     serverDb *tempDb = zcalloc(sizeof(serverDb) * server.dbnum);
-//
-//     tempDb->id = id;
-//     tempDb->keys = kvstoreCreate(&kvstoreKeysHashtableType, slot_count_bits, flags);
-//     tempDb->expires = kvstoreCreate(&kvstoreExpiresHashtableType, slot_count_bits, flags);
-//
-//     return tempDb;
-// }
+int dbHasNoKeys(int dbid) {
+    return dbid < 0 || dbid >= server.dbnum || !server.db[dbid] || kvstoreSize(server.db[dbid]->keys) == 0;
+}
+
 serverDb *createDatabase(int id) {
     int slot_count_bits = 0;
     int flags = KVSTORE_ALLOCATE_HASHTABLES_ON_DEMAND;
@@ -2763,10 +2747,11 @@ serverDb *createDatabase(int id) {
     return db;
 }
 
-void initDatabase(int id) {
+serverDb *createDatabaseIfNeeded(int id) {
     if (server.db[id] == NULL) {
         server.db[id] = createDatabase(id);
     }
+    return server.db[id];
 }
 
 void initServer(void) {
@@ -2842,7 +2827,7 @@ void initServer(void) {
     }
 
     server.db = zcalloc(sizeof(serverDb *) * server.dbnum);
-    initDatabase(0); /* The default database should always exist */
+    createDatabaseIfNeeded(0); /* The default database should always exist */
 
     evictionPoolAlloc(); /* Initialize the LRU keys pool. */
     /* Note that server.pubsub_channels was chosen to be a kvstore (with only one dict, which

src/server.h

@@ -3915,8 +3915,8 @@ void debugDelay(int usec);
 void killThreads(void);
 void makeThreadKillable(void);
 serverDb *createDatabase(int id);
-int databaseEmpty(int id);
-void initDatabase(int id);
+int dbHasNoKeys(int dbid);
+serverDb *createDatabaseIfNeeded(int id);
 void swapMainDbWithTempDb(serverDb **tempDb);
 sds getVersion(void);
 void debugPauseProcess(void);