Thread: WAL shipping with archive_timeout & pg_switch_xlog()

WAL shipping with archive_timeout & pg_switch_xlog()

From
wstrzalka
Date:
I have a question if it is possible that having archive_timeout set up
it will behave like pg_switch_xlog() in the term of non creating new
WAL when there are no changes in the database.

archive_timeout is used for WAL shipping to standby server in my case
(are there any other reasons?), but WAL is switched by the timeout
even if there are no changes on the server. pg_switch_xlog() is more
intelligent in this manner.
My case is that there are periods of time with no writes to database -
but the logs are continuously shipped. I would like to save some
resources if it's possible to change the default behavior.

I'm using PG 8.3.1

                            Thanks
                                     Wojtek Strzalka

Re: WAL shipping with archive_timeout & pg_switch_xlog()

From
Tom Lane
Date:
wstrzalka <wstrzalka@gmail.com> writes:
> archive_timeout is used for WAL shipping to standby server in my case
> (are there any other reasons?), but WAL is switched by the timeout
> even if there are no changes on the server.

This is intentional.  Some people consider the arrival of a new WAL file
to be a good heartbeat monitor, and they want to see one go by every
so many seconds whether the database is busy or not.

            regards, tom lane