> A "VACUUM FULL ANALYZE"  is performed every 3 hours.

The FULL part should not be necessary if you've set your max_fsm_pages high 

> Given there are 10080 minutes per week, the planner could, properly
> configured, estimate the number of rows returned by such a query to be:
> 10 min/ 10080 min  *  400,000 = 0.001 * 400,000 = 400.

The planner doesn't work that way.

> monitor=# explain analyze select * from "eventtable" where timestamp >

Hmmm.  What verison of PostgreSQL are you running?  I seem to remember an 
issue in one version with selecting comparisons against now().    What 
happens when you supply a constant instead of ( current_timestamp - interval 
'10 minutes' ) ?

> Here's something strange.  We try to disable sequential scans, but to no
> avail.  The estimated cost skyrockets, though:

That's how "enable_*=false" works in most cases.


Josh Berkus
Aglio Database Solutions
San Francisco

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