Fix Rows_query event when applying multi-packet queries

Summary:
THD maintains the length of the current query in a multi-query, we
should use that to extract only the current query to log in Rows_query event

Also removed unwanted special handling of Rows_query event handling metadata,
it's not a special event anymore.

Squash with D7002217

Reviewed By: yashtc

Differential Revision: D9003508

fbshipit-source-id: e13ff7f

Author: abhinav04sharma

client/mysqlbinlog.cc

@@ -1536,13 +1536,6 @@ Exit_status process_event(PRINT_EVENT_INFO *print_event_info, Log_event *ev,
       }
     }
     case ROWS_QUERY_LOG_EVENT:
-       // case: if events contains trx meta data print it else fall through
-       // like a normal rows query event
-       if (((Rows_query_log_event*) ev)->has_trx_meta_data())
-       {
-         ev->print(result_file, print_event_info);
-         break;
-       }
     case WRITE_ROWS_EVENT:
     case DELETE_ROWS_EVENT:
     case UPDATE_ROWS_EVENT:

sql/binlog.cc

@@ -8586,7 +8586,7 @@ int THD::binlog_write_table_map(TABLE *table, bool is_transactional,
     std::string query;
     if (opt_binlog_trx_meta_data)
       query.append(gen_trx_metadata());
-    query.append(this->query());
+    query.append(this->query(), this->query_length());
 
     /* Write the Rows_query_log_event into binlog before the table map */
     Rows_query_log_event rows_query_ev(this, query.c_str(), query.length());