PostgreSQL Logging – Impact of Logrotate on Log Files

logpostgresql

I have installed

PostgreSQL 10.6 on x86_64-redhat-linux-gnu, compiled by gcc (GCC) 8.2.1 20180905 (Red Hat 8.2.1-3), 64-bit

And configured:

log_filename = 'postgresql.log'

But I would like to manage log rotations by logrotate instead of internal logrotation by PostgreSQL:

#vim /etc/logrotate.d/postgresql

/var/lib/pgsql/data/log/postgresql.log {
    daily
    rotate 7
    compress
    create 0664 postgres postgres
    missingok
    notifempty
    sharedscripts
}

Where logrotate works as expected but PostgreSQL will stop logging into the rotated /var/lib/pgsql/data/log/postgresql.log file. The only resolution is to systemctl restart postgresql which could be placed inside logrotate postrotate/endscript block but I can't do it this way if this is done on critical production system.

Do you have any advice how to properly logrotate PostgreSQL log file without need of restarting PostgreSQL?

Thanks!

UPDATE:
During reloading of PostgreSQL it looks for changes. I found a workaround how to achieve that PostgreSQL will start to log into rotated postgresql.log file – I need to modify config file, for example comment out/modify log_filename then reload PostgreSQL and revert changes back and reload PostgreSQL again. Because PostgreSQL looks for changes in configuration file. But I would be glad if there is another better solution than touching configuration file.

Best Answer

You can try using the copytruncate directive of logrotate if you can accept the small risk of losing log data.

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