On Nov 17, 2011, at 5:12 PM, Ben Chobot wrote: > I have two queries in PG 9.1. One uses an index like I would like, the other does not. Is this expected behavior? If so, is there any way around it? I don't think you want the group by in that first query. Cheers, Steve > > > postgres=# explain analyze select min(id) from delayed_jobs where strand='sis_batch:account:15' group by strand; > QUERY PLAN > -------------------------------------------------------------------------------------------------------------------------- > GroupAggregate (cost=0.00..8918.59 rows=66 width=29) (actual time=226.759..226.760 rows=1 loops=1) > -> Seq Scan on delayed_jobs (cost=0.00..8553.30 rows=72927 width=29) (actual time=0.014..169.941 rows=72268 loops=1) > Filter: ((strand)::text = 'sis_batch:account:15'::text) > Total runtime: 226.817 ms > (4 rows) > > postgres=# explain analyze select id from delayed_jobs where strand='sis_batch:account:15' order by id limit 1; > QUERY PLAN > --------------------------------------------------------------------------------------------------------------------------------------------------------- > Limit (cost=0.00..0.33 rows=1 width=8) (actual time=0.097..0.098 rows=1 loops=1) > -> Index Scan using index_delayed_jobs_on_strand on delayed_jobs (cost=0.00..24181.74 rows=72927 width=8) (actual time=0.095..0.095 rows=1 loops=1) > Index Cond: ((strand)::text = 'sis_batch:account:15'::text) > Total runtime: 0.129 ms > (4 rows) > > > -- > Sent via pgsql-performance mailing list (pgsql-performance@xxxxxxxxxxxxxx) > To make changes to your subscription: > http://www.postgresql.org/mailpref/pgsql-performance -- Sent via pgsql-performance mailing list (pgsql-performance@xxxxxxxxxxxxxx) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-performance
