On 11.04.2010 23:18, Scott Marlowe wrote:
> In both instances your number of rows estimated is WAY higher than the
> actual number of rows returned. Perhaps if you increased
> default_statistics_target to 100, 200, 500 etc. re-analyzed, and then
> reun explain analyze again.
>
> Also increasing work_mem might encourage the bitmap index scans to occur.
>
Increasing the statistics >= 500 indeed helped a lot and causes the
planner to choose a good plan. :)
I'm now thinking about increasing the default_statistics_target of the
whole server from the default (100) to 1000, because I have many tables
with similar data. As the size of the table index seems not change at
all, I wonder how much additional storage is needed? I only care about
runtime performance: are inserts/updates affected by this change? Or is
only analyze affected (only run once during the night)?
Thanks,
Corin