Re: Piggybacking vacuum I/O
| От | Pavan Deolasee |
|---|---|
| Тема | Re: Piggybacking vacuum I/O |
| Дата | |
| Msg-id | 2e78013d0701260827l37d16ec3j45a129e3b71542bf@mail.gmail.com обсуждение исходный текст |
| Ответ на | Re: Piggybacking vacuum I/O (Alvaro Herrera <alvherre@commandprompt.com>) |
| Ответы |
Re: Piggybacking vacuum I/O
|
| Список | pgsql-hackers |
On 1/26/07, Alvaro Herrera <alvherre@commandprompt.com> wrote:
Heikki Linnakangas wrote:
> I'd like to see still more evidence that it's a problem before we start
> changing that piece of code. It has served us well for years.
So the TODO could be "investigate whether caching pg_clog and/or
pg_subtrans in local memory can be useful for vacuum performance".
As Heikki suggested, we should also investigate the same for normal
backends as well.
It would also be interesting to investigate whether early setting of hint bits
can reduce subsequent writes of blocks. A typical case would be a large table
being updated heavily for a while, followed by SELECT queries. The SELECT
queries would set hint bits for the previously UPDATEd tuples (old and new
versions) and thus cause subsequent writes of those blocks for what could
have been read-only queries.
Thanks,
Pavan
EnterpriseDB http://www.enterprisedb.com
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