MXS-1075: MariaDB 10 GTID stored and shown only for transaction safety on

MariaDB 10 GTID is detected and stored only if transaction_safety
option is on.

SELECT @@gtid_current_pos and “maxadmin show service $service_name” can
return it

server/modules/routing/binlogrouter/blr_master.c

@@ -1357,49 +1357,50 @@ blr_handle_binlog_record(ROUTER_INSTANCE *router, GWBUF *pkt)
                 spinlock_release(&router->binlog_lock);
 
                 /**
-                 * Detect transactions in events
+                 * Detect transactions in events if trx_safe is set:
                  * Only complete transactions should be sent to sleves
+                 *
+                 * Now looking for:
+                 * - QUERY_EVENT: BEGIN | START TRANSACTION | COMMIT
+                 * - MariadDB 10 GTID_EVENT
+                 * - XID_EVENT for transactional storage engines
                  */
 
-                if (router->mariadb10_compat &&
+                if (router->trx_safe)
-                    hdr.event_type == MARIADB10_GTID_EVENT)
                 {
-                    /**
+                    if (router->mariadb10_compat &&
-                     * If MariaDB 10 compatibility:
+                        hdr.event_type == MARIADB10_GTID_EVENT)
-                     * check for MARIADB10_GTID_EVENT with flags:
-                     * this is the TRASACTION START detection.
-                     *
-                     */
-
-                    uint64_t n_sequence;
-                    uint32_t domainid;
-                    unsigned int flags;
-                    n_sequence = extract_field(ptr + MYSQL_HEADER_LEN + 1 + BINLOG_EVENT_HDR_LEN, 64);
-                    domainid = extract_field(ptr + MYSQL_HEADER_LEN + 1 + BINLOG_EVENT_HDR_LEN + 8, 32);
-                    flags = *(ptr + MYSQL_HEADER_LEN + 1 + BINLOG_EVENT_HDR_LEN + 8 + 4);
-
-                    if ((flags & (MARIADB_FL_DDL | MARIADB_FL_STANDALONE)) == 0)
                     {
-                        char mariadb_gtid[GTID_MAX_LEN + 1];
-                        snprintf(mariadb_gtid, GTID_MAX_LEN, "%u-%u-%lu",
-                                 domainid, hdr.serverid,
-                                 n_sequence);
-
-                        MXS_DEBUG("MariaDB GTID received: (%s). Current file %s, pos %lu",
-                                  mariadb_gtid,
-                                  router->binlog_name,
-                                  router->current_pos);
-
-                        spinlock_acquire(&router->binlog_lock);
-
-                        /* Save GTID */
-                        strcpy(router->mariadb_gtid, mariadb_gtid);
-
                         /**
-                         * Now mark the new open transaction
+                         * If MariaDB 10 compatibility:
+                         * check for MARIADB10_GTID_EVENT with flags:
+                         * this is the TRASACTION START detection.
                          */
-                        if (router->trx_safe)
+
+                        uint64_t n_sequence;
+                        uint32_t domainid;
+                        unsigned int flags;
+                        n_sequence = extract_field(ptr + MYSQL_HEADER_LEN + 1 + BINLOG_EVENT_HDR_LEN, 64);
+                        domainid = extract_field(ptr + MYSQL_HEADER_LEN + 1 + BINLOG_EVENT_HDR_LEN + 8, 32);
+                        flags = *(ptr + MYSQL_HEADER_LEN + 1 + BINLOG_EVENT_HDR_LEN + 8 + 4);
+
+                        if ((flags & (MARIADB_FL_DDL | MARIADB_FL_STANDALONE)) == 0)
                         {
+                            char mariadb_gtid[GTID_MAX_LEN + 1];
+                            snprintf(mariadb_gtid, GTID_MAX_LEN, "%u-%u-%lu",
+                                     domainid, hdr.serverid,
+                                     n_sequence);
+
+                            MXS_DEBUG("MariaDB GTID received: (%s). Current file %s, pos %lu",
+                                      mariadb_gtid,
+                                      router->binlog_name,
+                                      router->current_pos);
+
+                            spinlock_acquire(&router->binlog_lock);
+
+                            /**
+                             * Now mark the new open transaction
+                             */
                             if (router->pending_transaction.state > BLRM_NO_TRANSACTION)
                             {
                                 MXS_ERROR("A MariaDB 10 transaction "
@@ -1413,20 +1414,15 @@ blr_handle_binlog_record(ROUTER_INSTANCE *router, GWBUF *pkt)
 
                             router->pending_transaction.state = BLRM_TRANSACTION_START;
 
+                            /* Save the pending GTID details */
+                            strcpy(router->pending_transaction.gtid, mariadb_gtid);
+                            router->pending_transaction.start_pos = router->current_pos;
+                            router->pending_transaction.end_pos = 0;
                         }
 
                         spinlock_release(&router->binlog_lock);
                     }
-                }
 
-                /**
-                 * If trx_safe is set then look for:
-                 * - QUERY_EVENT: BEGIN | START TRANSACTION | COMMIT
-                 * - XID_EVENT for transactional storage edngines
-                 */
-
-                if (router->trx_safe)
-                {
                     if (hdr.event_type == QUERY_EVENT)
                     {
                         char *statement_sql;
@@ -1458,6 +1454,8 @@ blr_handle_binlog_record(ROUTER_INSTANCE *router, GWBUF *pkt)
                             }
 
                             router->pending_transaction.state = BLRM_TRANSACTION_START;
+                            router->pending_transaction.start_pos = router->current_pos;
+                            router->pending_transaction.end_pos = 0;
                         }
 
                         /* Check for COMMIT in non transactional store engines */
@@ -1465,7 +1463,6 @@ blr_handle_binlog_record(ROUTER_INSTANCE *router, GWBUF *pkt)
                         {
                             router->pending_transaction.state = BLRM_COMMIT_SEEN;
                         }
-
                         spinlock_release(&router->binlog_lock);
 
                         MXS_FREE(statement_sql);
@@ -1624,19 +1621,32 @@ blr_handle_binlog_record(ROUTER_INSTANCE *router, GWBUF *pkt)
                              * If transaction is closed:
                              *
                              * 1) Notify clients events can be read
-                             *  from router->binlog_position
+                             *    from router->binlog_position
-                             * 2) set router->binlog_position to
+                             * 2) Update last seen MariaDB 10 GTID
+                             * 3) set router->binlog_position to
                              *    router->current_pos
                              */
 
                             if (router->pending_transaction.state > BLRM_TRANSACTION_START)
                             {
+                                /* Update last seen MariaDB GTID */
+                                if (router->mariadb10_compat)
+                                {
+                                    strcpy(router->mariadb_gtid, router->pending_transaction.gtid);
+
+                                    /* The transaction has been saved.
+                                     * this poins to end of binlog:
+                                     * i.e. the position of a new event
+                                     */
+                                    router->pending_transaction.end_pos = router->current_pos;
+                                }
+
                                 spinlock_release(&router->binlog_lock);
 
                                 /* Notify clients events can be read */
                                 blr_notify_all_slaves(router);
 
-                                /* update binlog_position and set pending to 0 */
+                                /* update binlog_position and set pending to NO_TRX */
                                 spinlock_acquire(&router->binlog_lock);
 
                                 router->binlog_position = router->current_pos;

server/modules/routing/binlogrouter/blr_slave.c

@@ -646,15 +646,19 @@ blr_slave_query(ROUTER_INSTANCE *router, ROUTER_SLAVE *slave, GWBUF *queue)
         }
         else if ((strcasecmp(word, "@@gtid_current_pos") == 0) || (strcasecmp(word, "@@global.gtid_current_pos") == 0))
         {
-            char    heading[40]; /* to ensure we match the case in query and response */
+            char    heading[40];
             char mariadb_gtid[GTID_MAX_LEN + 1];
+            mariadb_gtid[0] = '\0';
             strcpy(heading, word);
+
             MXS_FREE(query_text);
 
-            /* Safely get router->mariadb_gtid */
+            if (router->mariadb10_compat)
-            spinlock_acquire(&router->binlog_lock);
+            {
-            strcpy(mariadb_gtid, router->mariadb_gtid);
+                spinlock_acquire(&router->binlog_lock);
-            spinlock_release(&router->binlog_lock);
+                strcpy(mariadb_gtid, router->mariadb_gtid);
+                spinlock_release(&router->binlog_lock);
+            }
 
             return blr_slave_send_var_value(router, slave, heading, mariadb_gtid, BLR_TYPE_STRING);
         }