Re: hung backends stuck in spinlock heavy endless loop

On Wed, Jan 14, 2015 at 9:05 AM, Tom Lane <tgl@sss.pgh.pa.us> wrote:
> Merlin Moncure <mmoncure@gmail.com> writes:
>> On Wed, Jan 14, 2015 at 8:41 AM, Tom Lane <tgl@sss.pgh.pa.us> wrote:
>>> What are the autovac processes doing (according to pg_stat_activity)?
>
>> pid,running,waiting,query
>> 7105,00:28:40.789221,f,autovacuum: VACUUM ANALYZE pg_catalog.pg_class
>
> Hah, I suspected as much.  Is that the one that's stuck in
> LockBufferForCleanup, or the other one that's got a similar
> backtrace to all the user processes?

Yes, it is pg_class is coming from  LockBufferForCleanup ().  As you
can see above, it has a shorter runtime.   So it was killed off once
about a half hour ago which did not free up the logjam.  However, AV
spawned it again and now it does not respond to cancel.

merlin