Re: pg_standby -l might destory the archived file - Mailing list pgsql-hackers

From Heikki Linnakangas
Subject Re: pg_standby -l might destory the archived file
Date
Msg-id 4A255EF6.5050001@enterprisedb.com
Whole thread Raw
In response to Re: pg_standby -l might destory the archived file  (Tom Lane <tgl@sss.pgh.pa.us>)
Responses Re: pg_standby -l might destory the archived file  (Tom Lane <tgl@sss.pgh.pa.us>)
List pgsql-hackers
Tom Lane wrote:
> Simon Riggs <simon@2ndQuadrant.com> writes:
>> err...I don't see *any* problem at all, since pg_standby does not do
>> step (1) in the way you say and therefore never does step (5). Any links
>> created are explicitly deleted in all cases at the end of recovery.
> 
> That's a good point; don't we recover files under names like
> RECOVERYXLOG, not under names that could possibly conflict with regular
> WAL files?

Yes. But we rename RECOVERYXLOG to 000000010000000000000057 or similar 
at the end of recovery, in exitArchiveRecovery().

Thinking about this some more, I think we should've changed 
exitArchiveRecovery() rather than RemoveOldXlogFiles(): it would be more 
robust if exitArchiveRecovery() always copied the last WAL file rather 
than just renamed it. It doesn't seem safe to rely on the file the 
symlink points to to be valid after recovery is finished, and we might 
write to it before it's recycled, so the current fix isn't complete.

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


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