Re: [HACKERS] strange behavior of UPDATE

Tom Lane wrote:
> 
> Those are attention-getting numbers, all right.  I think that the two
> equal-key problems I found last night might partially explain them;
> I suspect there are more that I have not found, too.  I will look into
> it some more.

Am I correct that update takes ~ 10% CPU with high disk activity?
(Unfortunately, no list archive after May 13, so I'm not able
to re-read thread).
Remember that update inserts new index tuples and most likely
index scan will see these tuples and fetch just inserted
heap tuples.

> Could you try the same queries with no indexes in place, and see what
> the time scaling is like then?  That would confirm or deny the theory
> that it's an index-update problem.
> 
> Question for the hackers list: are we prepared to install purely
> performance-related bug fixes at this late stage of the 6.5 beta cycle?
> Bad as the above numbers are, I hesitate to twiddle the btree code and
> risk breaking things with only a week of testing time to go...

Try to fix problems and run Edmund scripts to see are things
better than now. We can apply fixes after 6.5.

Vadim