[MDEV-14109] MyRocks port: do we need manual update of slave_gtid_info? Created: 2017-10-23  Updated: 2017-10-23

Status: Open
Project: MariaDB Server
Component/s: None
Fix Version/s: None

Type: Task Priority: Major
Reporter: Sergei Petrunia Assignee: Sergei Petrunia
Resolution: Unresolved Votes: 0
Labels: None

Issue Links:
Relates
relates to MDEV-9658 Make MyRocks in MariaDB stable Closed

 Description   

Upstream MyRocks has this patch:

commit 0f402cb8381ba9d8e71c93085a22e5a12589b6e3
 
Author: Santosh Praneeth Banda <santoshb@fb.com>
 
Date:   Thu Nov 5 13:54:45 2015 -0800
 
 
 
    Improve singled thread replication performance
 
    
    Summary:
 
    On slave we update the slave_gtid_info table through MySQL. Delegate this
 
    to storage engine which is more efficient. SQL threads updates the row information
 
    in THD structure. Storag engines (InnoDB and Rocksdb) uses this information and
 
    updates the slave_gtid_info table during prepare phase.

For the user, the server has a global @@slave_gtid_info variable. Possible values are ON, OFF, OPTIMIZED. OPTIMIZED only works for MyRocks and means that the storage engine takes care of maintaining the mysql.slave_gtid_info table.

ha_rocksdb.cc has code that manually updates slave_gtid_info to reflect the binlog position.

MariaDB's equivalent of slave_gtid_info is called gtid_slave_pos.

MariaDB currently doesn't have the SQL part of this feature. We could port it, but

  • it may be hard to put something like this into MariaDB 10.2
  • this does not seem like a priority task?

See also: MDEV-12179, per-engine gtid_slave_pos. It is only in MariaDB-10.3, though.

 Comments   
Comment by Sergei Petrunia [ 2017-10-23 ]

A stack trace of MariaDB slave updating gtid_slave_pos:

  #1  0x0000555555d874c3 in handler::ha_write_row (this=0x7fff78011ed8, buf=0x7fff78014cd8 "\377") at /home/psergey/dev-git/10.2-mariarocks/sql/handler.cc:5995
 
  #2  0x0000555555cba2c4 in rpl_slave_state::record_gtid (this=0x555557937ee0, thd=0x7fff64001550, gtid=0x7ffff41e7ba0, sub_id=4, in_transaction=true, in_statement=false) at /home/psergey/dev-git/10.2-mariarocks/sql/rpl_gtid.cc:579
 
  #3  0x0000555555ea3799 in Xid_log_event::do_apply_event (this=0x7fff64017250, rgi=0x7fff64000a90) at /home/psergey/dev-git/10.2-mariarocks/sql/log_event.cc:8412
 
  #4  0x0000555555a62223 in Log_event::apply_event (this=0x7fff64017250, rgi=0x7fff64000a90) at /home/psergey/dev-git/10.2-mariarocks/sql/log_event.h:1452
 
  #5  0x0000555555a571ff in apply_event_and_update_pos_apply (ev=0x7fff64017250, thd=0x7fff64001550, rgi=0x7fff64000a90, reason=0) at /home/psergey/dev-git/10.2-mariarocks/sql/slave.cc:3571
 
  #6  0x0000555555a57738 in apply_event_and_update_pos (ev=0x7fff64017250, thd=0x7fff64001550, rgi=0x7fff64000a90) at /home/psergey/dev-git/10.2-mariarocks/sql/slave.cc:3719
 
  #7  0x0000555555a57f4e in exec_relay_log_event (thd=0x7fff64001550, rli=0x555558725e98, serial_rgi=0x7fff64000a90) at /home/psergey/dev-git/10.2-mariarocks/sql/slave.cc:4009
 
  #8  0x0000555555a5b47a in handle_slave_sql (arg=0x5555587241d0) at /home/psergey/dev-git/10.2-mariarocks/sql/slave.cc:5148

Generated at Thu Feb 08 08:10:59 UTC 2024 using Jira 8.20.16#820016-sha1:9d11dbea5f4be3d4cc21f03a88dd11d8c8687422.