Check mysql-table-locks

Overview

Checks the rate of table locks that had to wait in MySQL/MariaDB. A high wait rate indicates contention between concurrent queries. Logic is taken from MySQLTuner script:mysql_stats(), v1.9.8.

Important Notes:

Data Collection:

  • Queries SHOW GLOBAL STATUS for Table_locks_immediate and Table_locks_waited

  • Calculates the immediate lock rate as Table_locks_immediate / (Table_locks_waited + Table_locks_immediate) * 100

Fact Sheet

Fact

Value

Check Plugin Download

https://github.com/Linuxfabrik/monitoring-plugins/tree/main/check-plugins/mysql-table-locks

Nagios/Icinga Check Name

check_mysql_table_locks

Check Interval Recommendation

Every hour

Can be called without parameters

Yes

Runs on

Cross-platform

Compiled for Windows

No

Requirements

User with no privileges, locked down to 127.0.0.1 - for example monitoring\@127.0.0.1. Usernames in MySQL/MariaDB are limited to 16 chars in specific versions.

3rd Party Python modules

pymysql

Help

usage: mysql-table-locks [-h] [-V] [--always-ok]
                         [--defaults-file DEFAULTS_FILE]
                         [--defaults-group DEFAULTS_GROUP] [--timeout TIMEOUT]

Checks the rate of table locks that had to wait in MySQL/MariaDB. A high wait
rate indicates contention between concurrent queries. Alerts when the lock
wait rate is too high.

options:
  -h, --help            show this help message and exit
  -V, --version         show program's version number and exit
  --always-ok           Always returns OK.
  --defaults-file DEFAULTS_FILE
                        MySQL/MariaDB cnf file to read parameters like user,
                        host and password from (instead of specifying them on
                        the command line). Example:
                        `/var/spool/icinga2/.my.cnf`. Default:
                        /var/spool/icinga2/.my.cnf
  --defaults-group DEFAULTS_GROUP
                        Group/section to read from in the cnf file. Default:
                        client
  --timeout TIMEOUT     Network timeout in seconds. Default: 3 (seconds)

Usage Examples

./mysql-table-locks --defaults-file=/var/spool/icinga2/.my.cnf

Output:

100% table locks acquired immediately (2.6K immediate / 2.6K locks).

States

  • OK if 95% or more of table locks were acquired immediately.

  • WARN if less than 95% of table locks were acquired immediately.

  • --always-ok suppresses all alerts and always returns OK.

Perfdata / Metrics

Name

Type

Description

mysql_pct_table_locks_immediate

Percentage

Table_locks_immediate / (Table_locks_waited + Table_locks_immediate) * 100

mysql_table_locks_immediate

Continuous Counter

Number of table locks which were completed immediately.

mysql_table_locks_waited

Continuous Counter

Number of table locks which had to wait. Indicates table lock contention.

Credits, License