Re: Possible Corrputed shared memory

On 1 August 2015 at 20:10, Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us> wrote:

> James Sebastian <james(dot)sebastian(at)gmail(dot)com> writes:
> > On 1 August 2015 at 19:43, Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us> wrote:
> >> Also, if it took that long to recover, you might have raised the
> >> checkpoint interval settings too high.
>
> > I am using the following parameters
>
> > checkpoint_segments = 10 (from OS default 3)
> > checkpoint_completion_target = 0.8 (from OS default 0.5)
> > archive_mode=on
> > archive_timeout=600
>
> [ scratches head... ] It should certainly not have taken very long to
> replay 10 WAL segments worth of data. I surmise that the problems
> you were having before the shutdown were worse than you thought, ie
> checkpoints were failing to complete, probably due to a persistent
> I/O error, so that there was a whole lot more than normal to replay
> after the last successful checkpoint. Is there any evidence of such
> distress in the postmaster log?
>

[....sigh....Thanks.....]

We had very slow application performance and many hanging threads as per
pgadmin -> server status
Also logs had the following which also indicating probably high I/O (as per
google search results)

2015-07-30 10:10:21 IST WARNING: pgstat wait timeout
2015-07-30 10:12:21 IST WARNING: pgstat wait timeout

I got hardware analysed and I am sure there was no disc problems as per
them.
Load on application was usual...and that brings me to this email list

Thanks for all the help so far. I am learning much and becoming little
more comfortable with dealing with postgres administration from pure os
admin background.

> regards, tom lane
>