Client side caching: implement trackingInvalidateKeysOnFlush()

src/db.c

@@ -417,6 +417,7 @@ void signalModifiedKey(redisDb *db, robj *key) {
 
 void signalFlushedDb(int dbid) {
     touchWatchedKeysOnFlush(dbid);
+    if (server.tracking_clients) trackingInvalidateKeysOnFlush(dbid);
 }
 
 /*-----------------------------------------------------------------------------

src/server.h

@@ -1638,6 +1638,7 @@ void enableTracking(client *c, uint64_t redirect_to);
 void disableTracking(client *c);
 void trackingRememberKeys(client *c);
 void trackingInvalidateKey(robj *keyobj);
+void trackingInvalidateKeysOnFlush(int dbid);
 
 /* List data type */
 void listTypeTryConversion(robj *subject, robj *value);

src/tracking.c

@@ -117,6 +117,40 @@ void trackingRememberKeys(client *c) {
     getKeysFreeResult(keys);
 }
 
+void sendTrackingMessage(client *c, long long hash) {
+    int using_redirection = 0;
+    if (c->client_tracking_redirection) {
+        client *redir = lookupClientByID(c->client_tracking_redirection);
+        if (!redir) {
+            /* We need to signal to the original connection that we
+             * are unable to send invalidation messages to the redirected
+             * connection, because the client no longer exist. */
+            if (c->resp > 2) {
+                addReplyPushLen(c,3);
+                addReplyBulkCBuffer(c,"tracking-redir-broken",21);
+                addReplyLongLong(c,c->client_tracking_redirection);
+            }
+            return;
+        }
+        c = redir;
+        using_redirection = 1;
+    }
+
+    /* Only send such info for clients in RESP version 3 or more. However
+     * if redirection is active, and the connection we redirect to is
+     * in Pub/Sub mode, we can support the feature with RESP 2 as well,
+     * by sending Pub/Sub messages in the __redis__:invalidate channel. */
+    if (c->resp > 2) {
+        addReplyPushLen(c,2);
+        addReplyBulkCBuffer(c,"invalidate",10);
+        addReplyLongLong(c,hash);
+    } else if (using_redirection && c->flags & CLIENT_PUBSUB) {
+        robj *msg = createStringObjectFromLongLong(hash);
+        addReplyPubsubMessage(c,TrackingChannelName,msg);
+        decrRefCount(msg);
+    }
+}
+
 /* This function is called from signalModifiedKey() or other places in Redis
  * when a key changes value. In the context of keys tracking, our task here is
  * to send a notification to every client that may have keys about such . */
@@ -134,37 +168,7 @@ void trackingInvalidateKey(robj *keyobj) {
         memcpy(&id,ri.key,ri.key_len);
         client *c = lookupClientByID(id);
         if (c == NULL) continue;
-        int using_redirection = 0;
+        sendTrackingMessage(c,hash);
-        if (c->client_tracking_redirection) {
-            client *redir = lookupClientByID(c->client_tracking_redirection);
-            if (!redir) {
-                /* We need to signal to the original connection that we
-                 * are unable to send invalidation messages to the redirected
-                 * connection, because the client no longer exist. */
-                if (c->resp > 2) {
-                    addReplyPushLen(c,3);
-                    addReplyBulkCBuffer(c,"tracking-redir-broken",21);
-                    addReplyLongLong(c,c->client_tracking_redirection);
-                }
-                continue;
-            }
-            c = redir;
-            using_redirection = 1;
-        }
-
-        /* Only send such info for clients in RESP version 3 or more. However
-         * if redirection is active, and the connection we redirect to is
-         * in Pub/Sub mode, we can support the feature with RESP 2 as well,
-         * by sending Pub/Sub messages in the __redis__:invalidate channel. */
-        if (c->resp > 2) {
-            addReplyPushLen(c,2);
-            addReplyBulkCBuffer(c,"invalidate",10);
-            addReplyLongLong(c,hash);
-        } else if (using_redirection && c->flags & CLIENT_PUBSUB) {
-            robj *msg = createStringObjectFromLongLong(hash);
-            addReplyPubsubMessage(c,TrackingChannelName,msg);
-            decrRefCount(msg);
-        }
     }
     raxStop(&ri);
 
@@ -173,3 +177,18 @@ void trackingInvalidateKey(robj *keyobj) {
     raxFree(TrackingTable[hash]);
     TrackingTable[hash] = NULL;
 }
+
+void trackingInvalidateKeysOnFlush(int dbid) {
+    UNUSED(dbid);
+    if (server.tracking_clients == 0) return;
+
+    listNode *ln;
+    listIter li;
+    listRewind(server.clients,&li);
+    while ((ln = listNext(&li)) != NULL) {
+        client *c = listNodeValue(ln);
+        if (c->flags & CLIENT_TRACKING) {
+            sendTrackingMessage(c,-1);
+        }
+    }
+}