Re: hung backends stuck in spinlock heavy endless loop

On Tue, Jan 13, 2015 at 5:49 PM, Peter Geoghegan <pg(at)heroku(dot)com> wrote:
> On Tue, Jan 13, 2015 at 3:21 PM, Andres Freund <andres(at)2ndquadrant(dot)com> wrote:
>> My guess is rather that it's contention on the freelist lock via
>> StrategyGetBuffer's. I've seen profiles like this due to exactly that
>> before - and it fits to parallel loading quite well.
>
> I'm not saying you're wrong, but the breakdown of _bt_moveright()
> relative to _bt_relandgetbuf() calls seems a bit fishy to me.
>
> I don't remember seeing _bt_moveright() or _bt_compare() figuring so
> prominently, where _bt_binsrch() is nowhere to be seen. I can't see a
> reference to _bt_binsrch() in either profile.

hm, this is hand compiled now, I bet the symbols are wrong.

merlin