| From: | Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us> |
|---|---|
| To: | Michael Paquier <michael(dot)paquier(at)gmail(dot)com> |
| Cc: | Andrey Lizenko <lizenko79(at)gmail(dot)com>, "pgsql-general(at)postgresql(dot)org" <pgsql-general(at)postgresql(dot)org> |
| Subject: | Re: temporary tables are logged somehow? |
| Date: | 2015-01-22 15:44:26 |
| Message-ID: | 23653.1421941466@sss.pgh.pa.us |
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| Lists: | pgsql-general |
Michael Paquier <michael(dot)paquier(at)gmail(dot)com> writes:
> On Thu, Jan 22, 2015 at 11:06 PM, Andrey Lizenko <lizenko79(at)gmail(dot)com> wrote:
>> 3. They are not WAL-logged.
>> Whats wrong with it in my case?
> Nothing. Temporary tables are not WAL-logged, but transaction commit is.
Right. I think there is some optimization for transactions that only
wrote temp-table data, but it could at most be skipping fsync of the
transaction commit record, not omitting generating it entirely.
Also, changes to the system catalogs are always WAL-logged; so creation
and deletion of a temp table cause some amount of WAL output, even if
manipulation of the table's contents does not.
regards, tom lane
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