database/mariadb
1
0
Fork 0
mirror of https://github.com/MariaDB/server.git synced 2025-12-01 17:39:21 +03:00
Code Activity

Bug#20685029: SLAVE IO THREAD SHOULD STOP WHEN DISK IS

Browse Source 
FULL
Bug#21753696: MAKE SHOW SLAVE STATUS NON BLOCKING IF IO
THREAD WAITS FOR DISK SPACE

Problem:
========
Currently SHOW SLAVE STATUS blocks if IO thread waits for
disk space. This makes automation tools verifying
server health block on taking relevant action. Finally this
will create SHOW SLAVE STATUS piles.

Analysis:
=========
SHOW SLAVE STATUS hangs on mi->data_lock if relay log write
is waiting for free disk space while holding mi->data_lock.
mi->data_lock is needed to protect the format description
event (mi->format_description_event) which is accessed by
the clients running FLUSH LOGS and slave IO thread. Note
relay log writes don't need to be protected by
mi->data_lock, LOCK_log is used to protect relay log between
IO and SQL thread (see MYSQL_BIN_LOG::append_event). The
code takes mi->data_lock to protect
mi->format_description_event during relay log rotate which
might get triggered right after relay log write.

Fix:
====
Release the data_lock just for the duration of writing into
relay log.

Made change to ensure the following lock order is maintained
to avoid deadlocks.

data_lock, LOCK_log

data_lock is held during relay log rotations to protect
the description event.
This commit is contained in:
Sujatha Sivakumar
2016-03-01 12:29:51 +05:30
parent bb32ac1d9b
commit 8361151765
13 changed files with 443 additions and 47 deletions
Download Patch File Download Diff File Expand all files Collapse all files

31
mysql-test/include/rpl_init.inc
View File

@@ -43,6 +43,7 @@
#
# [--let $rpl_server_count= 7]
# --let $rpl_topology= 1->2->3->1->4, 2->5, 6->7
# [--let $rpl_extra_connections_per_server= 1]
# [--let $rpl_check_server_ids= 1]
# [--let $rpl_skip_change_master= 1]
# [--let $rpl_skip_start_slave= 1]
@@ -65,6 +66,12 @@
# want to specify the empty topology (no server replicates at
# all), you have to set $rpl_topology=none.
#
# $rpl_extra_connections_per_server
# By default, this script creates connections server_N and
# server_N_1. If you can set this variable to a number, the
# script creates:
# server_N, server_N_1, ..., server_N_$rpl_extra_connections_per_server
#
# $rpl_check_server_ids
# If $rpl_check_server_ids is set, this script checks that the
# @@server_id of all servers are different. This is normally
@@ -139,8 +146,17 @@ if (!$SERVER_MYPORT_4)
# Check that $rpl_server_count is set
if (!$rpl_server_count)
{
--let $_compute_rpl_server_count= `SELECT REPLACE('$rpl_topology', '->', ',')`
--let $rpl_server_count= `SELECT GREATEST($_compute_rpl_server_count)`
--let $rpl_server_count= `SELECT REPLACE('$rpl_topology', '->', ',')`
if (`SELECT LOCATE(',', '$rpl_server_count')`)
{
--let $rpl_server_count= `SELECT GREATEST($rpl_server_count)`
}
}
--let $_rpl_extra_connections_per_server= $rpl_extra_connections_per_server
if ($_rpl_extra_connections_per_server == '')
{
--let $_rpl_extra_connections_per_server= 1
}
@@ -159,15 +175,20 @@ if (!$rpl_debug)
# Create two connections to each server; reset master/slave, select
# database, set autoinc variables.
--let $_rpl_server= $rpl_server_count
--let $_rpl_one= _1
--let $underscore= _
while ($_rpl_server)
{
# Connect.
--let $rpl_server_number= $_rpl_server
--let $rpl_connection_name= server_$_rpl_server
--source include/rpl_connect.inc
--let $rpl_connection_name= server_$_rpl_server$_rpl_one
--source include/rpl_connect.inc
--let $_rpl_connection_number= 1
while ($_rpl_connection_number <= $_rpl_extra_connections_per_server)
{
--let $rpl_connection_name= server_$_rpl_server$underscore$_rpl_connection_number
--source include/rpl_connect.inc
--inc $_rpl_connection_number
}
# Configure server.
--let $rpl_connection_name= server_$_rpl_server