Fix resize hash tables stuck on the last non-empty slot

soloestoy · Nov 23, 2023 · 58e2bf2 · 58e2bf2
1 parent 4634769
commit 58e2bf2
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Showing 2 changed files with 13 additions and 14 deletions.
diff --git a/src/db.c b/src/db.c
@@ -682,7 +682,7 @@ long long emptyDbStructure(redisDb *dbarray, int dbnum, int async,
         dbarray[j].expires_cursor = 0;
         for (dbKeyType subdict = DB_MAIN; subdict <= DB_EXPIRES; subdict++) {
             dbarray[j].sub_dict[subdict].key_count = 0;
-            dbarray[j].sub_dict[subdict].resize_cursor = 0;
+            dbarray[j].sub_dict[subdict].resize_cursor = -1;
             if (server.cluster_enabled) {
                 if (dbarray[j].sub_dict[subdict].rehashing)
                     listEmpty(dbarray[j].sub_dict[subdict].rehashing);

diff --git a/src/server.c b/src/server.c
@@ -641,20 +641,19 @@ int htNeedsResize(dict *dict) {
  * In non cluster-enabled setup, it resize main/expires dictionary based on the same condition described above. */
 void tryResizeHashTables(int dbid) {
     redisDb *db = &server.db[dbid];
-    int slot = 0;
     for (dbKeyType subdict = DB_MAIN; subdict <= DB_EXPIRES; subdict++) {
-        dbIterator *dbit = dbIteratorInitFromSlot(db, subdict, db->sub_dict[subdict].resize_cursor);
-        for (int i = 0; i < CRON_DBS_PER_CALL; i++) {
-            dict *d = dbGetDictFromIterator(dbit);
-            slot = dbIteratorGetCurrentSlot(dbit);
-            dbIteratorNextDict(dbit);
-            if (!d) break;
-            if (htNeedsResize(d))
-                dictResize(d);
+        if (dbSize(db, subdict)) {
+            if (db->sub_dict[subdict].resize_cursor == -1)
+                db->sub_dict[subdict].resize_cursor = findSlotByKeyIndex(db, 1, subdict);
+
+            for (int i = 0; i < CRON_DBS_PER_CALL && db->sub_dict[subdict].resize_cursor != -1; i++) {
+                int slot = db->sub_dict[subdict].resize_cursor;
+                dict *d = subdict == DB_MAIN ? db->dict[slot] : db->expires[slot];
+                if (htNeedsResize(d))
+                    dictResize(d);
+                db->sub_dict[subdict].resize_cursor = dbGetNextNonEmptySlot(db, slot, subdict);
+            }
         }
-        /* Save current iterator position in the resize_cursor. */
-        db->sub_dict[subdict].resize_cursor = slot;
-        dbReleaseIterator(dbit);
     }
 }
 
@@ -2637,7 +2636,7 @@ void initDbState(redisDb *db){
     for (dbKeyType subdict = DB_MAIN; subdict <= DB_EXPIRES; subdict++) {
         db->sub_dict[subdict].rehashing = listCreate();
         db->sub_dict[subdict].key_count = 0;
-        db->sub_dict[subdict].resize_cursor = 0;
+        db->sub_dict[subdict].resize_cursor = -1;
         db->sub_dict[subdict].slot_size_index = server.cluster_enabled ? zcalloc(sizeof(unsigned long long) * (CLUSTER_SLOTS + 1)) : NULL;
         db->sub_dict[subdict].bucket_count = 0;
     }