database/mariadb
1
0
Fork 0
mirror of https://github.com/MariaDB/server.git synced 2025-07-27 18:02:13 +03:00
Code Activity

MDEV-9519: Data corruption will happen on the Galera cluster size change

Browse Source 
If we have a 2+ node cluster which is replicating from an async master
and the binlog_format is set to STATEMENT and multi-row inserts are executed
on a table with an auto_increment column such that values are automatically
generated by MySQL, then the server node generates wrong auto_increment
values, which are different from what was generated on the async master.

In the title of the MDEV-9519 it was proposed to ban start slave on a Galera
if master binlog_format = statement and wsrep_auto_increment_control = 1,
but the problem can be solved without such a restriction.

The causes and fixes:

1. We need to improve processing of changing the auto-increment values
after changing the cluster size.

2. If wsrep auto_increment_control switched on during operation of
the node, then we should immediately update the auto_increment_increment
and auto_increment_offset global variables, without waiting of the next
invocation of the wsrep_view_handler_cb() callback. In the current version
these variables retain its initial values if wsrep_auto_increment_control
is switched on during operation of the node, which leads to inconsistent
results on the different nodes in some scenarios.

3. If wsrep auto_increment_control switched off during operation of the node,
then we must return the original values of the auto_increment_increment and
auto_increment_offset global variables, as the user has set. To make this
possible, we need to add a "shadow copies" of these variables (which stores
the latest values set by the user).

https://jira.mariadb.org/browse/MDEV-9519
This commit is contained in:
Julius Goryavsky
2019-02-15 10:58:59 +01:00
committed by Jan Lindström
parent 28cb041754
commit 243f829c1c
17 changed files with 392 additions and 81 deletions
Download Patch File Download Diff File Expand all files Collapse all files

2
sql/sql_insert.cc
View File

@ -1862,7 +1862,6 @@ int write_record(THD *thd, TABLE *table,COPY_INFO *info)
info->deleted++;
else
error= 0;
thd->record_first_successful_insert_id_in_cur_stmt(table->file->insert_id_for_cur_row);
/*
Since we pretend that we have done insert we should call
its after triggers.
@ -1903,7 +1902,6 @@ int write_record(THD *thd, TABLE *table,COPY_INFO *info)
if (table->file->insert_id_for_cur_row == 0)
table->file->insert_id_for_cur_row= insert_id_for_cur_row;
thd->record_first_successful_insert_id_in_cur_stmt(table->file->insert_id_for_cur_row);
/*
Restore column maps if they where replaced during an duplicate key
problem.