> There are about 2500 rows in that table.
>
> 1st query explain analyze: Seq Scan on PRIORITY_STATISTICS
> (cost=0.00..491.44 rows=127 width=12) (actual time=98.58..98.58 rows=0
> loops=1)
> Total runtime: 98.74 msec
>
> 2nd query explain analyze: NOTICE: QUERY PLAN:
>
> Index Scan using PRIORITY_STATISTICS_reo_id, PRIORITY_STATISTICS_reo_id,
[snip]
> PRIORITY_STATISTICS_reo_id on PRIORITY_STATISTICS (cost=0.00..394.06
> rows=102 width=12) (actual time=20.93..20.93 rows=0 loops=1)
> Total runtime: 21.59 msec
With only 2500 rows the planner could be deciding that it's going to have to read every disk block to do an index scan
anyway,so it
might as well do a sequential scan. If the pages are in fact in the kernel cache then the compute time will dominate,
notthe IO
time, so it ends up looking like a bad plan, but it's probably not really such a bad plan...
Is your effective_cache_size set to something sensibly large?
You could also try decreasing cpu_index_tuple_cost and cpu_tuple_cost. These will affect all your queries though, so
whatyou gain
on one might be lost on another.
Matt
