Re: simple update queries take a long time - postgres 8.3.1

On Mon, Mar 31, 2008 at 12:23 PM, Raymond O'Donnell <rod(at)iol(dot)ie> wrote:

> On 31/03/2008 20:16, mark wrote:
> > is the query I am running , and it takes over 10 seconds to complete
> > this query...
> >
> >
> > update users set number_recieved=number_recieved+1 where uid=738889333;
> >
> > table has about 1.7 million rows.. i have an index on column uid and
> > also on number_received. .. this is also slowing down the inserts that
> > happen.
>
> Are you VACUUMing the table regularly?

I have this setting on in postgresql.conf.. I dont manually do vaccum..

autovacuum = on # Enable autovacuum subprocess? 'on'

> Also, can you show us the EXPLAIN ANALYZE output from the query?

EXPLAIN ANALYZE update users set number_recieved=number_recieved+1 where
uid=738889333;
QUERY PLAN
------------------------------------------------------------------------------------------------------------------
Index Scan using idx_uid on users (cost=0.00..8.46 rows=1 width=1073)
(actual time=0.094..0.161 rows=1 loops=1)
Index Cond: (uid = 738889333)
Total runtime: 11479.053 ms
(3 rows)