"Todd A. Cook" <tcook@blackducksoftware.com> writes:
"Todd A. Cook" <tcook@blackducksoftware.com> writes:
> QUERY PLAN
> -------------------------------------------------------------------------
> HashAggregate (cost=1163446.13..1163448.63 rows=200 width=4)
> -> Seq Scan on oom_tab (cost=0.00..867748.42 rows=59139542 width=4)
>
> The row estimitate for oom_tab is close to the actual value. Most of
> the values are unique, however, so the result should have around 59M
> rows too.
ouch. it's estimating 200 distinct values. The estimates for distinct values
are known to be unreliable but they shouldn't be *that* bad. Do you have a few
hundred extremely common values and then a few million other values?
What does this say:
select * from pg_statistic where starelid = (select oid from pg_class where relname = 'oom_tab')
You may need to reanalyze and maybe increase the statistics target
(possibly by a lot). It may be interesting to compare the results of the above
query before and after analyzing too.
--
greg
