Showing posts with label mysql binary logs. Show all posts
Showing posts with label mysql binary logs. Show all posts

Monday, January 12, 2015

mysql binary logs


Please do not just delete them in the OS.
You need to let mysqld do that for you. Here is how mysqld manages it:
The file mysql-bin.index keeps a list of all binary logs mysqld has generated and auto-rotated. The mechanisms for cleaning out the binlogs in conjunction with mysql-bin.index are:
PURGE BINARY LOGS TO 'binlogname';
PURGE BINARY LOGS BEFORE 'datetimestamp';
These will clear all binary logs before the binlog or timestamp you just specified.
For example, if you run
PURGE BINARY LOGS TO 'mysql-bin.000223';
this will erase all binary logs before 'mysql-bin.000223'.
If you run
PURGE BINARY LOGS BEFORE DATE(NOW() - INTERVAL 3 DAY) + INTERVAL 0 SECOND;
this will erase all binary logs before midnight 3 days ago.
If you want to have binlog rotated away automatically and keep 3 days woth, simply set this:
mysql> SET GLOBAL expire_logs_days = 3;
then add this to /etc/my.cnf
[mysqld]
expire-logs-days=3
and mysqld will delete them logs for you

SHOW SLAVE STATUS\G

This is critical. When you run SHOW SLAVE STATUS\G, you will see two binary logs from the Master:
  • Master_Log_File
  • Relay_Master_Log_File
When replication has little or no lag these are usually the same value. When there is a lot of replication lag, these values are different. Just to make it simple, choose whatever Relay_Master_Log_File is, and go back to the Master and run
PURGE BINARY LOGS TO 'Whatever Relay_Master_Log_File Is';
That way, replication is not interrupted.
Give it a Try !!!

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