Re: 9.2beta1, parallel queries, ReleasePredicateLocks, CheckForSerializableConflictIn in the oprofile

On Fri, 25 May 2012, Merlin Moncure wrote:
> how likely is it to see multiple simultaneous scans in the real world?
> Interleaving scans like that is not a very effective optimization --
> if it was me, it'd be trying to organize something around a
> partitioned tid scan for parallel sequential access.

Regarding the "real world use". I can say for myself is that the reason I'm
running the queries like the ones I have in my test is that I have a large
inflow of data every day, tens of gb, which has to be processed and since PG
doesn't have any parallelization of queries built in, and running the
processing in a single thread will take too long, I'm trying to work around
that by manually running multiple threads in PG and trying to split the work
among them. So not having scalability here is going to hurt us (but I
admit that it's probably not very popular use-case for PG).

Regards,
S

*****************************************************
Sergey E. Koposov, PhD, Research Associate
Institute of Astronomy, University of Cambridge
Madingley road, CB3 0HA, Cambridge, UK
Tel: +44-1223-337-551 Web: http://www.ast.cam.ac.uk/~koposov/