| From: | Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us> |
|---|---|
| To: | pgsql-hackers(at)postgresql(dot)org, "Simon Riggs" <simon(at)2ndquadrant(dot)com> |
| Cc: | "Bruce Momjian" <bruce(at)momjian(dot)us>, "Joshua D(dot) Drake" <jd(at)commandprompt(dot)com>, pgsql-patches(at)postgresql(dot)org |
| Subject: | Re: COPY with no WAL, in certain circumstances |
| Date: | 2007-01-07 02:18:02 |
| Message-ID: | 2036.1168136282@sss.pgh.pa.us |
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| Lists: | pgsql-hackers pgsql-patches |
"Simon Riggs" <simon(at)2ndquadrant(dot)com> writes:
> The rule is: if the relfilenode for a table is new in this transaction
> (and therefore the whole things will be dropped at end-of-transaction)
> then *all* COPY commands are able to avoid writing WAL safely, if:
> - PITR is not enabled
> - there is no active portal (which could have been opened on an earlier
> commandid and could therefore see data prior to the switch to the new
> relfilenode). In those cases, *not* using WAL causes no problems at all,
> so sleep well without it.
Uh ... what in the world has an active portal got to do with it?
I think you've confused snapshot considerations with crash recovery.
regards, tom lane
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