Check mysql-innodb-log-waits

Overview

Checks the number of times InnoDB was forced to wait for log writes to be flushed due to the log buffer being too small in MySQL/MariaDB. Logic is taken from MySQLTuner script:mysql_innodb(), v1.8.3.

Hints:

  • On RHEL 7+, one way to install the Python MySQL Connector is via pip install pymysql

  • Compared to check_mysql / MySQLTuner this check currently:

    • supports only simple login with username/password (not via SSL/TLS)

    • does not support a connection via socket

Fact Sheet

Check Plugin Download

https://github.com/Linuxfabrik/monitoring-plugins/tree/main/check-plugins/mysql-innodb-log-waits

Check Interval Recommendation

Once an hour

Can be called without parameters

Yes

Available for

Python 3, Windows

Requirements

Python module pymysql; 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.

Help

usage: mysql-innodb-log-waits [-h] [-V] [--always-ok] [-H HOSTNAME]
                              [-p PASSWORD] [--port PORT] [-u USERNAME]

Checks the number of times InnoDB was forced to wait for log writes to be
flushed due to the log buffer being too small 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.
  -H HOSTNAME, --hostname HOSTNAME
                        MySQL/MariaDB hostname. Default: 127.0.0.1
  -p PASSWORD, --password PASSWORD
                        Use the indicated password to authenticate the
                        connection. Default:
  --port PORT           MySQL/MariaDB port. Default: 3306
  -u USERNAME, --username USERNAME
                        MySQL/MariaDB username. Default: root

Usage Examples

./mysql-innodb-log-waits --hostname localhost --username root --password mypassword

Output:

0.0 InnoDB log buffer waits / 867.6K writes.

States

  • WARN if the number of times InnoDB was forced to wait for log writes to be flushed is > 0.

Perfdata / Metrics

Name

Type

Description

mysql_innodb_log_buffer_size

Bytes

Size in bytes of the buffer for writing InnoDB redo log files to disk. Increasing this means larger transactions can run without needing to perform disk I/O before committing.

mysql_innodb_log_waits

Continous Counter

Number of times InnoDB was forced to wait for log writes to be flushed due to the log buffer being too small.

mysql_innodb_log_writes

Continous Counter

Number of writes to the InnoDB redo log.

Credits, License