Reason for lot of small relay log file formation. I Have setup a slave and it relay log rotates to soon and creates thousands of relay log file.whats the reason for more relay log formation.


Two possible reasons seem to stick out, ensure your server_id is different on both the master and the slave. This is to be defined at startup in the cnf file.

Another option is you specified a very tiny max_binlog_size or max_relay_log_size, ensure the values are what you want and not off by an order of magnitude (eg. 512k instead of 512M)


Here is one for the ages

I wrote an answer to a post on Jan 02, 2015 entitled mysql replication master 5.5 slave 5.1 error on create database. In that post, I learned from my boss about this strange situation when I was replicating from a MySQL 5.5 Master to a MySQL 5.6 Slave.

In short, I learned from some additional research that binary log events can change size and shape between major releases of MySQL.

This situation caused the following on the Slave:

  • mysqld crashed
  • mysqld_safe looped back and restarted mysqld
  • --skip-slave-start was not configured
  • mysqld crashed and restarted indefinitely
  • relay logs piled up to the heavens
  • I had to kill mysqld_safe to stop this craziness.

The solution for this scenario was to upgrade the Master to 5.6.

I also have a 3.5 year old post (Tons and tons of relay logs on a master) covering other situations.

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