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Check mysql-binlog-cache

Overview

Checks if a certain amount of transactions used a temporary disk cache because they could not fit in the regular binary log cache in 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-binlog-cache
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-binlog-cache [-h] [-V] [--always-ok]
                          [--defaults-file DEFAULTS_FILE]
                          [--defaults-group DEFAULTS_GROUP]
                          [--timeout TIMEOUT]

Checks if a certain amount of transactions used a temporary disk cache because
they could not fit in the regular binary log cache in 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-binlog-cache --defaults-file=/var/spool/icinga2/.my.cnf

Output:

0% binlog cache memory access (0 memory / 0 total).

States

  • WARN if more than 10% of all transactions using the binary log cache are read from disk.

Perfdata / Metrics

Name Type Description
mysql_binlog_cache_disk_use Continous Counter Number of transactions which used a temporary disk cache because they could not fit in the regular binary log cache, being larger than binlog_cache_size.
mysql_binlog_cache_size Bytes If the binary log is active, this variable determines the size in bytes, per-connection, of the cache holding a record of binary log changes during a transaction.
mysql_binlog_cache_use Continous Counter Number of transaction which used the regular binary log cache, being smaller than binlog_cache_size.
mysql_pct_binlog_cache Percentage (Binlog_cache_use - Binlog_cache_disk_use) / Binlog_cache_use * 100

Credits, License