Re: SV: MySQL and PostgreSQL speed compare

Поиск
Список
Период
Сортировка
От Stephan Szabo
Тема Re: SV: MySQL and PostgreSQL speed compare
Дата
Msg-id Pine.BSF.4.21.0012291102570.18941-100000@megazone23.bigpanda.com
обсуждение исходный текст
Ответ на SV: MySQL and PostgreSQL speed compare  ("Jarmo Paavilainen" <netletter@comder.com>)
Список pgsql-general
> >>> Sir, thanks for sharing this with us. However, unless you can explain
> >>> why queries inside of transactions run faster than queries outside of
> >>> transactions, I would be inclined to mistrust the test. I haven't
>
> I was suprised too. But the only difference is that I do a "BEGIN" before I
> start inserting/modifying/deleting and then when Im done I do a "COMMIT".
> Everything between those are exactly the same. Ive been told that MySQL does
> not support transactions (by default) so there the test is broken. And with
> PostgreSQL, well something inside PostgreSQL is broken (it cant be right
> that with transaction PostgreSQL is 10 times faster than without).

All PostgreSQL statements are in some transaction.  If you're not using
explicit transactions (ie, autocommit) then it's effectively wrapping the
statement in a transaction block of its own, so you're doing the
transaction start/end (including any necessary file access) <n> times
rather than once which is probably most of the difference you're seeing.


В списке pgsql-general по дате отправления:

Предыдущее
От: "Mikheev, Vadim"
Дата:
Сообщение: RE: MySQL and PostgreSQL speed compare
Следующее
От: "Robert D. Nelson"
Дата:
Сообщение: RE: MySQL and PostgreSQL speed compare