Details
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Bug
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Status: Closed (View Workflow)
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Minor
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Resolution: Fixed
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None
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None
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None
Description
I'm not sure if it's a bug, maybe it's supposed to work this way, but it surely looks strange, so I'll file it and leave it to you to decide
When a slave is actively replicating, most of the time @@gtid_current_pos and @@gtid_slave_pos appear to be empty. No special flow seems to be necessary, just regular DML would suffice. For example, the test below performs a thousand of inserts on master while checking the values on the slave at the same time. Here is a typical extract from the output:
Variable_name Value
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gtid_binlog_pos 0-1-513
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gtid_current_pos
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gtid_slave_pos
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Variable_name Value
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gtid_binlog_pos 0-1-523
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gtid_current_pos
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gtid_slave_pos
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Variable_name Value
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gtid_binlog_pos 0-1-530
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gtid_current_pos 0-1-530
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gtid_slave_pos 0-1-530
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Variable_name Value
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gtid_binlog_pos 0-1-540
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gtid_current_pos
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gtid_slave_pos
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Variable_name Value
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gtid_binlog_pos 0-1-548
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gtid_current_pos
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gtid_slave_pos
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Variable_name Value
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gtid_binlog_pos 0-1-559
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gtid_current_pos
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gtid_slave_pos
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If instead of a number of small statements I execute one very big statement, the effect can still be observed, but the empty values only appear during a small fraction of time. So, I presume the "empty phase" has somewhat flat duration per an event group, regardless its size.
Test case:
--source include/master-slave.inc
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--source include/have_innodb.inc
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--source include/have_binlog_format_row.inc
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--connection slave
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--source include/stop_slave.inc
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change master to master_use_gtid=current_pos; |
--source include/start_slave.inc
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--connection master
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create table t1 (i int, c varchar(8)) engine=InnoDB; |
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--delimiter |
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create procedure p(n int) |
begin
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while n > 0 do
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insert into t1 values (1,'test1'),(2,'test2'),(3,'test3'),(4,'test4'); |
set n = n - 1; |
end while; |
end| |
--delimiter ;
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send call p(1000);
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--connection slave
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let $run = 100;
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--disable_query_log
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while ($run)
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{
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SHOW VARIABLES LIKE 'gtid%pos'; |
--sleep 1 |
dec $run; |
}
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--connection master
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--reap
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drop table t1; |
drop procedure p; |
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--sync_slave_with_master
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--connection master
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--source include/rpl_end.inc
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bzr version-info
revision-id: sergii@pisem.net-20130610064025-makoe3xkewwwky8j
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revno: 3761
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branch-nick: 10.0
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Attachments
Issue Links
- relates to
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MDEV-26 Global transaction ID
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- Closed
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