Re: [SQL] Yet Another (Simple) Case of Index not used

On Sat, Apr 19, 2003 at 12:03:18PM -0700, Josh Berkus wrote:
> Kevin, Tom:
>
> > (The cheapness can be disputed as well, since it creates a single point
> > of contention for all inserts and deletes on the table.  But that's a
> > different topic.)
>
> Actually, this was the problem with the trigger method of maintaining COUNT
> information in PostgreSQL.   The statistics table itself becomes a
> significant souce of delay, since if a table_A gets 10,000 rows updated than
> table_count_A must necessarily be updated 10,000 times ... creating a lot of
> dead tuples and severely attenuating the table on disk until the next vacuum
> ... resulting in Update #10,000 to table_count_A taking 100+ times as long as
> Update #1 does, due to the required random seek time on disk.

Once statement level triggers are implimented, the performance would
probably be fine, assuming your update was a single statement.
--
Jim C. Nasby (aka Decibel!)                    jim@nasby.net
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