Re: 8.1 iss

[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]

 



"PostgreSQL" <martin@xxxxxxxxxxx> writes:

...
> As I post this, the query is approaching an hour of run time.  I've listed 
> an explain of the query and my non-default conf parameters below.  Please 
> advise on anything I should change or try, or on any information I can 
> provide that could help diagnose this.
> 
> 
> GroupAggregate  (cost=9899282.83..10285434.26 rows=223858 width=15)
>   Filter: (count(*) > 1)
>   ->  Sort  (cost=9899282.83..9994841.31 rows=38223392 width=15)
>         Sort Key: v_barcode
>         ->  Seq Scan on lead  (cost=0.00..1950947.92 rows=38223392 width=15)
> 
> shared_buffers = 50000
> work_mem = 16384
...

It sounds to me like it's doing a large on-disk sort. Increasing work_mem
should improve the efficiency. If you increase it enough it might even be able
to do it in memory, but probably not.

The shared_buffers is excessive but if you're using the default 8kB block
sizes then it 400MB of shared pages on a 16GB machine ought not cause
problems. It might still be worth trying lowering this to 10,000 or so.

Is this a custom build from postgresql.org sources? RPM build? Or is it a BSD
ports or Gentoo build with unusual options?

Perhaps posting actual vmstat and iostat output might help if someone catches
something you didn't see?

-- 
greg



[Postgresql General]     [Postgresql PHP]     [PHP Users]     [PHP Home]     [PHP on Windows]     [Kernel Newbies]     [PHP Classes]     [PHP Books]     [PHP Databases]     [Yosemite]

  Powered by Linux