Saurabh Agrawal <saurabh.miet@gmail.com> wrote:
> max_standby_archive_delay = -1
>
> I noticed that whenever long running query executes on slave,
> slave starts lagging by master and as soon as query completes log
> files get applied immediately. Please help how can I avoid slave
> lag.
You can adjust max_standby_archive_delay to the maximum amount of
time you want replication to block waiting for your query. If that
is exceeded, your query will be canceled to allow replication to
continue.
http://www.postgresql.org/docs/9.0/interactive/hot-standby.html#HOT-STANDBY-CONFLICT
-Kevin