MXS-1266: Standalone events in transaction (no COMMIT event) are now handled

Standalone events in transaction (no COMMIT event) are now handled:

the GTID is saved to gtid_maps storage.

Transaction detection assumes there is only one query_event after GTID
event with MARIADB_FL_STANDALONE flag set.

server/modules/routing/binlogrouter/blr.h

@@ -543,7 +543,8 @@ typedef enum
     BLRM_NO_TRANSACTION,       /*< No transaction */
     BLRM_TRANSACTION_START,    /*< A transaction is open*/
     BLRM_COMMIT_SEEN,          /*< Received COMMIT event in the current trx */
-    BLRM_XID_EVENT_SEEN        /*< Received XID event of current transaction */
+    BLRM_XID_EVENT_SEEN,       /*< Received XID event of current transaction */
+    BLRM_STANDALONE_SEEN       /*< Received a standalone event, ie: a DDL */
 } master_transaction_t;
 
 /** MariaDB GTID elements */
@@ -562,6 +563,8 @@ typedef struct pending_transaction
     uint64_t start_pos;              /** The BEGIN pos */
     uint64_t end_pos;                /** The next_pos in COMMIT event*/
     MARIADB_GTID_ELEMS gtid_elms;    /* MariaDB 10.x GTID components */
+    bool standalone;                 /** Standalone event, such as DDL
+                                      * no terminating COMMIT */
 } PENDING_TRANSACTION;
 
 /** MariaDB GTID info */

server/modules/routing/binlogrouter/blr_file.c

@@ -2051,8 +2051,13 @@ blr_read_events_all_events(ROUTER_INSTANCE *router,
                 domainid = extract_field(ptr + 8, 32);
                 flags = *(ptr + 8 + 4);
 
-                if ((flags & (MARIADB_FL_DDL | MARIADB_FL_STANDALONE)) == 0)
+                /**
-                {
+                 * Detect whether it's a standalone transaction:
+                 * there is no terminating COMMIT event.
+                 * i.e: a DDL or FLUSH TABLES etc
+                 */
+                router->pending_transaction.standalone = flags & MARIADB_FL_STANDALONE;
+
                 if (pending_transaction > BLRM_NO_TRANSACTION)
                 {
                     MXS_ERROR("Transaction cannot be @ pos %llu: "
@@ -2102,7 +2107,6 @@ blr_read_events_all_events(ROUTER_INSTANCE *router,
                 }
             }
         }
-        }
 
         /**
          * Check for GTID_LIST_EVENT
@@ -2179,6 +2183,7 @@ blr_read_events_all_events(ROUTER_INSTANCE *router,
          *
          * Check for BEGIN ( ONLY for mysql 5.6, mariadb 5.5 )
          * Check for COMMIT (not transactional engines)
+         * Check for pending standalone transaction
          */
 
         if (hdr.event_type == QUERY_EVENT)
@@ -2238,11 +2243,33 @@ blr_read_events_all_events(ROUTER_INSTANCE *router,
 
                         if (!(debug & BLR_CHECK_ONLY))
                         {
-                            MXS_DEBUG("       Transaction @ pos %llu, closing @ %llu",
+                            MXS_DEBUG("       Transaction @ pos %llu,"
-                                      last_known_commit, pos);
+                                      " closing @ %llu",
+                                      last_known_commit,
+                                      pos);
                         }
                     }
                 }
+
+                /**
+                 * If it's a standalone transaction event we're done:
+                 * This query event, only one, terminates the
+                 * transaction.
+                 */
+                if (pending_transaction > BLRM_NO_TRANSACTION &&
+                    router->pending_transaction.standalone)
+                {
+                    pending_transaction = BLRM_STANDALONE_SEEN;
+
+                    if (!(debug & BLR_CHECK_ONLY))
+                    {
+                        MXS_DEBUG("       Standalone Transaction @ pos %llu,"
+                                  " closing @ %llu",
+                                  last_known_commit,
+                                  pos);
+                    }
+                }
+
                 MXS_FREE(statement_sql);
             }
             else
@@ -2263,8 +2290,10 @@ blr_read_events_all_events(ROUTER_INSTANCE *router,
 
                 if (!(debug & BLR_CHECK_ONLY))
                 {
-                    MXS_DEBUG("       Transaction XID @ pos %llu, closing @ %llu",
+                    MXS_DEBUG("       Transaction XID @ pos %llu,"
-                              last_known_commit, pos);
+                              " closing @ %llu",
+                              last_known_commit,
+                              pos);
                 }
             }
         }
@@ -2273,11 +2302,15 @@ blr_read_events_all_events(ROUTER_INSTANCE *router,
         {
             if (!(debug & BLR_CHECK_ONLY))
             {
-                MXS_DEBUG("< Transaction @ pos %llu, is now closed @ %llu. %lu events seen",
+                MXS_DEBUG("< Transaction @ pos %llu, is now closed @ %llu."
-                          last_known_commit, pos, transaction_events);
+                          " %lu events seen",
+                          last_known_commit,
+                          pos,
+                          transaction_events);
             }
 
             pending_transaction = BLRM_NO_TRANSACTION;
+            router->pending_transaction.standalone = false;
 
             router->pending_transaction.end_pos = hdr.next_pos;
 
@@ -3485,7 +3518,6 @@ static int gtid_select_cb(void *data, int cols, char** values, char** names)
  * @param    result  The (allocated) ouput data to fill
  * @return   True if with found GTID or false
  */
-
 bool blr_fetch_mariadb_gtid(ROUTER_SLAVE *slave,
                             const char *gtid,
                             MARIADB_GTID_INFO *result)

server/modules/routing/binlogrouter/blr_master.c

@@ -1041,6 +1041,7 @@ blr_handle_binlog_record(ROUTER_INSTANCE *router, GWBUF *pkt)
 
                 if (router->trx_safe)
                 {
+                    // MariaDB 10 GTID event check
                     if (router->mariadb10_compat &&
                         hdr.event_type == MARIADB10_GTID_EVENT)
                     {
@@ -1057,10 +1058,15 @@ blr_handle_binlog_record(ROUTER_INSTANCE *router, GWBUF *pkt)
                         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)
-                        {
                         spinlock_acquire(&router->binlog_lock);
 
+                        /**
+                        * Detect whether it's a standalone transaction:
+                        * there is no terminating COMMIT event.
+                        * i.e: a DDL or FLUSH TABLES etc
+                        */
+                        router->pending_transaction.standalone = flags & MARIADB_FL_STANDALONE;
+
                         /**
                          * Now mark the new open transaction
                          */
@@ -1106,8 +1112,8 @@ blr_handle_binlog_record(ROUTER_INSTANCE *router, GWBUF *pkt)
 
                         spinlock_release(&router->binlog_lock);
                     }
-                    }
 
+                    // Query Event check
                     if (hdr.event_type == QUERY_EVENT)
                     {
                         char *statement_sql;
@@ -1148,6 +1154,17 @@ blr_handle_binlog_record(ROUTER_INSTANCE *router, GWBUF *pkt)
                         {
                             router->pending_transaction.state = BLRM_COMMIT_SEEN;
                         }
+
+                        /**
+                         * If it's a standalone transaction event we're done:
+                         * this query event, only one, terminates the transaction.
+                         */
+                        if (router->pending_transaction.state > BLRM_NO_TRANSACTION &&
+                            router->pending_transaction.standalone)
+                        {
+                            router->pending_transaction.state = BLRM_STANDALONE_SEEN;
+                        }
+
                         spinlock_release(&router->binlog_lock);
 
                         MXS_FREE(statement_sql);
@@ -1326,7 +1343,10 @@ blr_handle_binlog_record(ROUTER_INSTANCE *router, GWBUF *pkt)
                                 spinlock_acquire(&router->binlog_lock);
 
                                 router->binlog_position = router->current_pos;
+
+                                /* Set no pending transaction and no standalone */
                                 router->pending_transaction.state = BLRM_NO_TRANSACTION;
+                                router->pending_transaction.standalone = false;
 
                                 spinlock_release(&router->binlog_lock);
                             }

server/modules/routing/binlogrouter/blr_slave.c

@@ -6826,7 +6826,8 @@ static bool blr_handle_set_stmt(ROUTER_INSTANCE *router,
         MXS_ERROR("%s: Incomplete set command.", router->service->name);
         return false;
     }
-    else if ((strcasecmp(word, "autocommit") == 0) || (strcasecmp(word, "@@session.autocommit") == 0))
+    else if ((strcasecmp(word, "autocommit") == 0) ||
+             (strcasecmp(word, "@@session.autocommit") == 0))
     {
         blr_slave_send_ok(router, slave);
         return true;