On Wed, Nov 25, 2015 at 3:43 AM, Albe Laurenz <laurenz.albe@xxxxxxxxxx> wrote:
Alex Williams wrote:
> Concerning these two params below, when using hot_standby_feedback, what would you set them if you
> had the situation where you had queries constantly running on the standby, some quick and some long,
> practically all day/night, everyday?
>
> max_standby_archive_delay (integer)
> max_standby_streaming_delay (integer)
> Should I still keep them as -1 (infinite)?
I'd say set them both to 0.
If you have hot_standby_feedback=on, the primary will not remove any rows still
needed on the standby, so there should never be a need to delay WAL application.
hot_standby_feedback will significantly reduce the conflicts but it will not totally eliminate them. For example if a new column is added to a table, any query using this table on slave will be cancelled to apply this change.
IF query cancellation is totally not acceptable then you will have to set these delays to -1.
The drawback is that you may get considerable bloat on the primary if many
DELETE/UPDATE operation are going on and queries on the standby take a long time.
Yours,
Laurenz Albe
