Re: Do we still have locking problems with concurrentusers

Awesome!

Thanks Neil.

:-)

Regards and best wishes,

Justin Clift

Neil Conway wrote:
>
> On Tue, 2002-03-05 at 21:59, Bruce Momjian wrote:
> > Justin Clift wrote:
> > > Hi all,
> > >
> > > One of the things which the AS3AP benchmark does is have multiple users
> > > access a table with hash indexes on it.
> > >
> > > With the OSDB (Open Source Database Benchmark: http://osdb.sf.net) we've
> > > found on PG 7.1 that multiple clients hitting a table using a hash index
> > > generates locking problems. I remember Tom mentioning that this is a
> > > known thing, but I'm not sure if this has been fixed since then.
>
> No, it hasn't been fixed yet.
>
> > > Does anyone have any ideas? If not, would someone be willing to take
> > > the time to fix it?
> >
> > It has not been fixed. One TODO item is to either stop mentioning hash
> > at all or get it improved. We have been sitting on the fence for too
> > long.
>
> I'll be working on fixing this. I'm also going to try to add more
> features to the hash index implementation: for example, allow UNIQUE
> hash indexes, hash indexes over multiple keys, etc. My first improvement
> to the hash code, replacing the hash function with a better one, is on
> the unapplied patches list and should be in CVS soon. Bruce, can you add
> my name to the TODO list next to this item?
>
> BTW, does anyone have any tips for debugging deadlock conditions? I
> normally debug problems by running a backend under gdb in standalone
> mode, but that obviously won't help for this problem. Any further advice
> on improving hash index concurrency would be very welcome...
>
> Justin:
>
> Cheers,
>
> Neil
>
> --
> Neil Conway <neilconway(at)rogers(dot)com>
> PGP Key ID: DB3C29FC

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