Search Postgresql Archives

Re: Out of memory error in 8.1.0 Win32

[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]

 



"Todd A. Cook" <tcook@xxxxxxxxxxxxxxxxxxxxx> writes:

"Todd A. Cook" <tcook@xxxxxxxxxxxxxxxxxxxxx> 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



[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]
[Index of Archives]     [Postgresql Jobs]     [Postgresql Admin]     [Postgresql Performance]     [Linux Clusters]     [PHP Home]     [PHP on Windows]     [Kernel Newbies]     [PHP Classes]     [PHP Books]     [PHP Databases]     [Postgresql & PHP]     [Yosemite]
  Powered by Linux