Fixed SHOW TABLES FROM ... queries being routed to the active database instead of the one defined in the query.

server/modules/routing/dbshard/shardrouter.c

@@ -35,6 +35,7 @@
 #include <modutil.h>
 #include <mysql_client_server_protocol.h>
 
+
 MODULE_INFO info = {
     MODULE_API_ROUTER,
     MODULE_BETA_RELEASE,
@@ -303,7 +304,8 @@ bool subsvc_is_valid(SUBSERVICE* sub)
     spinlock_release(&sub->service->spin);
 
     if(ses_state == SESSION_STATE_ROUTER_READY &&
-       svc_state == SERVICE_STATE_STARTED)
+       (svc_state != SERVICE_STATE_FAILED ||
+        svc_state != SERVICE_STATE_STOPPED))
     {
         return true;
     }
@@ -359,7 +361,8 @@ get_shard_target_name(ROUTER_INSTANCE* router, ROUTER_CLIENT_SES* client, GWBUF*
     HASHTABLE* ht = client->dbhash;
     int sz = 0, i, j;
     char** dbnms = NULL;
-    char* rval = NULL;
+    char *rval = NULL;
+    char *query = NULL,*tmp = NULL;
     bool has_dbs = false; /**If the query targets any database other than the current one*/
 
     if(!query_is_parsed(buffer))
@@ -385,14 +388,35 @@ get_shard_target_name(ROUTER_INSTANCE* router, ROUTER_CLIENT_SES* client, GWBUF*
         free(dbnms);
     }
 
+    if(QUERY_IS_TYPE(qtype, QUERY_TYPE_SHOW_TABLES))
+    {
+        query = modutil_get_SQL(buffer);
+        if((tmp = strstr(query,"from")))
+        {
+            char* tok = strtok(tmp, " ;");
+            tok = strtok(NULL," ;");
+            ss_dassert(tok != NULL);
+            tmp = (char*) hashtable_fetch(ht, tok);
+        }
+        free(query);
+        
+        if(tmp == NULL)
+        {
+            rval = (char*) hashtable_fetch(ht, client->rses_mysql_session->db);
+        }
+        else
+        {
+            rval = tmp;
+        }
+    }
+    
+    if(rval == NULL && !has_dbs && client->rses_mysql_session->db[0] != '\0')
+    {
         /**
          * If the query contains no explicitly stated databases proceed to
          * check if the session has an active database and if it is sharded.
          */
 
-    if(QUERY_IS_TYPE(qtype, QUERY_TYPE_SHOW_TABLES) ||
-       (rval == NULL && !has_dbs && client->rses_mysql_session->db[0] != '\0'))
-    {
         rval = (char*) hashtable_fetch(ht, client->rses_mysql_session->db);
     }
    
@@ -446,36 +470,37 @@ tokenize_string(char* str)
  * @return returns 1 for success and 0 for error
  */
 static int
-filterReply (FILTER* instance, void *session, GWBUF *reply)
+filterReply(FILTER* instance, void *session, GWBUF *reply)
 {
 
-    ROUTER_CLIENT_SES* rses = (ROUTER_CLIENT_SES*)instance;
+    ROUTER_CLIENT_SES* rses = (ROUTER_CLIENT_SES*) instance;
     SUBSERVICE* subsvc;
-    int i,rv = 1;
+    int i, rv = 1;
     bool mapped = true;
     sescmd_cursor_t* scur;
     GWBUF* tmp = NULL;
 
+
     if(!rses_begin_locked_router_action(rses))
     {
         return 0;
     }
 
-    subsvc = get_subsvc_from_ses(rses,session);
+    subsvc = get_subsvc_from_ses(rses, session);
 
     if(SUBSVC_IS_WAITING(subsvc))
     {
-        subsvc_clear_state(subsvc,SUBSVC_WAITING_RESULT);
+        subsvc_clear_state(subsvc, SUBSVC_WAITING_RESULT);
     }
 
-    subsvc_clear_state(subsvc,SUBSVC_QUERY_ACTIVE);
+    subsvc_clear_state(subsvc, SUBSVC_QUERY_ACTIVE);
 
     if(!rses->hash_init)
     {
-        subsvc_set_state(subsvc,SUBSVC_MAPPED);
+        subsvc_set_state(subsvc, SUBSVC_MAPPED);
-        parse_mapping_response(rses,subsvc->service->name,reply);
+        parse_mapping_response(rses, subsvc->service->name, reply);
 
-        for(i = 0;i<rses->n_subservice;i++)
+        for(i = 0; i < rses->n_subservice; i++)
         {
             if(SUBSVC_IS_OK(rses->subservice[i]) && !SUBSVC_IS_MAPPED(rses->subservice[i]))
             {
@@ -490,20 +515,32 @@ filterReply (FILTER* instance, void *session, GWBUF *reply)
         if(mapped)
         {
             rses->hash_init = true;
+            if(rses->queue)
+            {
                 tmp = rses->queue;
+                rses->queue = rses->queue->next;
+            }
         }
 
         goto retblock;
     }
 
 
+
+    if(rses->queue)
+    {
+        tmp = rses->queue;
+        rses->queue = rses->queue->next;
+    }
+
+
     scur = subsvc->scur;
 
     if(sescmd_cursor_is_active(scur))
     {
         if(!sescmd_cursor_next(scur))
         {
-                sescmd_cursor_set_active(scur,false);
+            sescmd_cursor_set_active(scur, false);
         }
         else
         {
@@ -514,11 +551,11 @@ filterReply (FILTER* instance, void *session, GWBUF *reply)
 
     rv = SESSION_ROUTE_REPLY(rses->session, reply);
 
-    retblock:
+retblock:
     rses_end_locked_router_action(rses);
     if(tmp)
     {
-        routeQuery((ROUTER*)rses->router,rses,tmp);
+        rv = routeQuery((ROUTER*) rses->router, rses, tmp);
     }
     return rv;
 }
@@ -1262,12 +1299,40 @@ routeQuery(ROUTER* instance,
     }
     ss_dassert(!GWBUF_IS_TYPE_UNDEFINED(querybuf));
 
+    /** Lock router session */
+    if(!rses_begin_locked_router_action(router_cli_ses))
+    {
+        LOGIF(LT, (skygw_log_write(
+                                   LOGFILE_TRACE,
+                                   "Route query aborted! Routing session is closed <")));
+        ret = 0;
+        goto retblock;
+    }
+    
     if(!router_cli_ses->hash_init)
+    {
+        GWBUF* tmp = router_cli_ses->queue;
+        
+        while(tmp && tmp->next)
+        {
+            tmp = tmp->next;
+        }
+        
+        if(tmp == NULL)
         {
             router_cli_ses->queue = querybuf;
+        }
+        else
+        {
+            tmp->next = querybuf;
+        }
+              
+        rses_end_locked_router_action(router_cli_ses);        
         return 1;
     }
     
+    rses_end_locked_router_action(router_cli_ses);
+    
     packet = GWBUF_DATA(querybuf);
     packet_type = packet[4];
 
@@ -1419,28 +1484,9 @@ routeQuery(ROUTER* instance,
     else if(route_target != TARGET_ALL &&
             (tname = get_shard_target_name(inst, router_cli_ses, querybuf, qtype)) != NULL)
     {
-        bool shard_ok = true;
 
-
-        if(shard_ok)
-        {
         route_target = TARGET_NAMED_SERVER;
     }
-        else
-        {
-
-            /**
-             * Shard is not a viable target right now so we check
-             * for an alternate backend with the database. If this is not found
-             * the target is undefined and an error will be returned to the client.
-             */
-
-            if((tname = get_shard_target_name(inst, router_cli_ses, querybuf, qtype)) != NULL)
-            {
-                route_target = TARGET_NAMED_SERVER;
-            }
-        }
-    }
 
     if(TARGET_IS_UNDEFINED(route_target))
     {