Re: Move tablespace - Mailing list pgsql-hackers

From Heikki Linnakangas
Subject Re: Move tablespace
Date
Msg-id 4BCEE395.4090000@enterprisedb.com
Whole thread Raw
In response to Re: Move tablespace  (Simon Riggs <simon@2ndQuadrant.com>)
Responses Re: Move tablespace  (Simon Riggs <simon@2ndQuadrant.com>)
List pgsql-hackers
Simon Riggs wrote:
> On Tue, 2010-04-20 at 21:03 -0400, Tom Lane wrote:
>> Simon Riggs <simon@2ndQuadrant.com> writes:
>>> Following patch writes a new WAL record that just says "copy foo to
>>> newts" and during replay we flush buffers and then re-execute the copy
>>> (but only when InArchiveRecovery). So the copy happens locally on the
>>> standby, not copying from primary to standby. We do this just with a
>>> little refactoring and a simple new WAL message.
>> And what happens to crash-recovery replay?  You can't have it both ways,
>> either the data is in WAL or it's missing.
> 
> The patch changes nothing in the case of crash recovery.

What happens if the record is replayed twice in archive recovery? For
example if you stop and restart a standby server after it has replayed
that record. What does the 2nd redo attempt do if the source file was
already deleted by the 1st recovery.

I also think we shouldn't be fiddling with this at this stage in the
release cycle.

--  Heikki Linnakangas EnterpriseDB   http://www.enterprisedb.com


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