Re: [HACKERS] strange behavior of UPDATE

Поиск
Список
Период
Сортировка
От Tom Lane
Тема Re: [HACKERS] strange behavior of UPDATE
Дата
Msg-id 3969.927659810@sss.pgh.pa.us
обсуждение исходный текст
Ответ на Re: [HACKERS] strange behavior of UPDATE  (Edmund Mergl <E.Mergl@bawue.de>)
Список pgsql-hackers
Edmund Mergl <E.Mergl@bawue.de> writes:
> Some more numbers:

>   database         #rows      inserts    create      make_sqs    make_nqs
>                                           index      selects     updates
> ----------------------------------------------------------------------------
>     pgsql         10.000       00:24      00:09       00:16       00:25
>     pgsql        100.000       04:01      01:29       01:06       49:45
>     pgsql      1.000.000       39:24      20:49       23:42       ???

> whereas the increase of elapsed time is somewhat proportional
> to the number of rows, for the update-case it is rather
> exponential.

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.

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...
        regards, tom lane


В списке pgsql-hackers по дате отправления:

Предыдущее
От: Tom Lane
Дата:
Сообщение: Re: [HACKERS] pg_dump core dump, upgrading from 6.5b1 to 5/24 snapshot
Следующее
От: jwieck@debis.com (Jan Wieck)
Дата:
Сообщение: Re: [HACKERS] INSERT INTO view means what exactly?