Re: Abnormal performance difference between Postgres and MySQL

[Scott Marlowe <scott(dot)marlowe(at)gmail(dot)com>]

On Wed, Feb 25, 2009 at 2:32 PM, Farhan Husain <russoue(at)gmail(dot)com> wrote:
>
> On Wed, Feb 25, 2009 at 3:30 PM, Robert Haas <robertmhaas(at)gmail(dot)com> wrote:
>>
>> On Wed, Feb 25, 2009 at 3:44 PM, Farhan Husain <russoue(at)gmail(dot)com> wrote:
>> > Initially, it was the default value (32MB). Later I played with that
>> > value
>> > thinking that it might improve the performance. But all the values
>> > resulted
>> > in same amount of time.
>>
>> Well, if you set it back to what we consider to be a reasonable value,
>> rerun EXPLAIN ANALYZE, and post that plan, it might help us tell you
>> what to do next.
>>
>> ...Robert
>
> Right now I am running the query again with 32MB work_mem. It is taking a
> long time as before. However, I have kept the following values unchanged:
>
> shared_buffers = 32MB                   # min 128kB or max_connections*16kB

That's REALLY small for pgsql.  Assuming your machine has at least 1G
of ram, I'd set it to 128M to 256M as a minimum.