From: | Venkata Balaji Nagothi <vbnpgc(at)gmail(dot)com> |
---|---|
To: | Shaun Duncan <shaun(dot)duncan(at)gmail(dot)com> |
Cc: | "pgsql-general(at)postgresql(dot)org >> PG-General Mailing List" <pgsql-general(at)postgresql(dot)org> |
Subject: | Re: Hot standby read slaves exceed max delay on WAL segment. Replication lag. |
Date: | 2014-03-19 21:08:36 |
Message-ID: | CAHBAh5sfV7yELt6h3vZpvmkMY2fGCH1pB_Spd34wgoGE7G_JZQ@mail.gmail.com |
Views: | Raw Message | Whole Thread | Download mbox | Resend email |
Thread: | |
Lists: | pgsql-general |
On Thu, Mar 20, 2014 at 4:12 AM, Shaun Duncan <shaun(dot)duncan(at)gmail(dot)com>wrote:
This is on a production 9.0.15 install with 1 master, 5 hot standby read
> only slaves.
>
> We've been trying to look into a situation where we're seeing that hot
> standby read slaves are receiving WAL segments, but are exceeding
> max_standby_archive_delay (60s) and max_standby_streaming_delay (60s) and
> not applying changes. The slave will get the first segment and hang (we've
> seen up to 30m before removing the slave from our read pool to catch up)
> and get further and further behind the master. Furthermore, we have seen
> that after a slave has caught up, putting it back into the read pool will
> mean will almost immediately start to see this happen again. It acts as if
> we had max_standby_* set to -1.
>
> I'm just looking for some ideas, hints, or suggestions as to what might be
> going on here or what we might be doing wrong.
>
>
Have you noticed if the read requests on standby database are taking long
and loading up the server ? If yes, any idea why the queries on standby are
taking long to complete ?
WAL replay would be paused ( until the read requests are served ) at the
time of conflicting queries on the standby site.
Also, Do you see any delay in master sending the WALs to standby ?
Venkata Balaji N
Sr. Database Administrator
Fujitsu Australia
From | Date | Subject | |
---|---|---|---|
Next Message | Vik Fearing | 2014-03-19 21:59:21 | Re: How to access NEW or OLD field given only the field's name? |
Previous Message | Adrian Klaver | 2014-03-19 21:06:44 | Re: How to access NEW or OLD field given only the field's name? |