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Check mysql-sorts

Overview

Checks some sort metrics on MySQL/MariaDB. Logic is taken from MySQLTuner script:mysql_stats(), v1.9.8.

Hints:

Fact Sheet

Fact Value
Check Plugin Download https://github.com/Linuxfabrik/monitoring-plugins/tree/main/check-plugins/mysql-sorts
Check Interval Recommendation Every 5 minutes
Can be called without parameters Yes
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-sorts [-h] [-V] [--always-ok] [--defaults-file DEFAULTS_FILE]
                   [--defaults-group DEFAULTS_GROUP] [--timeout TIMEOUT]

Checks some sort metrics on MySQL/MariaDB.

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
                        Specifies a cnf file to read parameters like user,
                        host and password from (instead of specifying them on
                        the command line), for 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-sorts --defaults-file=/var/spool/icinga2/.my.cnf

Output:

901.6K sorts used a full table scan. Sorts requiring temporary tables: 0% (0.0 temp sorts / 3.1M sorts).

States

  • WARN if there are more than 10% sort merge passes (sorts requiring temporary tables).

Perfdata / Metrics

Name Type Description
mysql_pct_temp_sort_table Percentage sort_merge_passes / total_sorts * 100
mysql_read_rnd_buffer_size Bytes Size in bytes of the buffer used when reading rows from a MyISAM table in sorted order after a key sort.
mysql_sort_buffer_size Bytes Each session performing a sort allocates a buffer with this amount of memory. Not specific to any storage engine.
mysql_sort_merge_passes Continous Counter Number of merge passes performed by the sort algorithm.
mysql_sort_range Continous Counter Number of sorts which used a range.
mysql_sort_scan Continous Counter Number of sorts which used a full table scan.
mysql_total_sorts Continous Counter sort_scan + sort_range

Credits, License