database/mariadb
1
0
Fork 0
mirror of https://github.com/MariaDB/server.git synced 2025-08-31 22:22:30 +03:00
Code Activity

MDEV-7818: Deadlock occurring with parallel replication and FTWRL

Browse Source 
Problem is that FLUSH TABLES WITH READ LOCK first blocks threads from
starting new commits, then waits for running commits to complete. But
in-order parallel replication needs commits to happen in a particular
order, so this can easily deadlock.

To fix this problem, this patch introduces a way to temporarily pause
the parallel replication worker threads. Before starting FTWRL, we let
all worker threads complete in-progress transactions, and then
wait. Then we proceed to take the global read lock. Once the lock is
obtained, we unpause the worker threads. Now commits are blocked from
starting by the global read lock, so the deadlock will no longer occur.
This commit is contained in:
Kristian Nielsen
2015-10-22 11:18:34 +02:00
parent 6d96fab7dd
commit ba02550166
8 changed files with 537 additions and 25 deletions
Download Patch File Download Diff File Expand all files Collapse all files

1
mysql-test/suite/perfschema/r/stage_mdl_global.result
View File

@@ -6,6 +6,7 @@ user1 statement/sql/flush flush tables with read lock
username event_name nesting_event_type
username event_name nesting_event_type
user1 stage/sql/init STATEMENT
user1 stage/sql/init STATEMENT
user1 stage/sql/query end STATEMENT
user1 stage/sql/closing tables STATEMENT
user1 stage/sql/freeing items STATEMENT