Re: pg_dump and thousands of schemas

On Thu, May 31, 2012 at 4:07 PM, Tatsuo Ishii <ishii@postgresql.org> wrote:
>> On Thu, May 31, 2012 at 10:45 AM, Tatsuo Ishii <ishii@postgresql.org> wrote:
>>> Just for record, I rerun the test again with my single-LOCK patch, and
>>> now total runtime of pg_dump is 113 minutes.
>>> 188 minutes(9.0)->125 minutes(git master)->113 minutes(with my patch).
>>>
>>> So far, I'm glad to see 40% time savings at this point.
>>
>> I see only 9.6% savings (100 * (113/125 - 1)).  What am I missing?
>
> What I meant was (100 * (113/188 - 1)).

OK, my fault was to assume you wanted to measure only your part, while
apparently you meant overall savings.  But Tom had asked for separate
measurements if I understood him correctly.  Also, that measurement of
your change would go after the O(N^2) fix.  It could actually turn out
to be much more than 9% because the overall time would be reduced even
more dramatic.  So it might actually be good for your fix to wait a
bit. ;-)

Kind regards

robert

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