Re: Warm-standby robustness question

["Kevin Grittner" <Kevin(dot)Grittner(at)wicourts(dot)gov>]

>>> On Tue, Dec 18, 2007 at 12:55 PM, in message <3149(dot)1198004157(at)sss(dot)pgh(dot)pa(dot)us>,
Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us> wrote: 
> "David F. Skoll" <dfs(at)roaringpenguin(dot)com> writes:
>> My question is this:  If the master database is fairly busy, gets
>> VACUUMed once a day, etc. can we expect the warm standby server
>> to work correctly after days/weeks/months/years of log shipping,
>> or should we periodically take new base backups?
> 
> I don't think the time period is at issue.  Log-shipping should keep the
> slave a perfect replica of the master (if it doesn't, we have problems
> anyway).
 
Except for hint bits.  This becomes more of a post-recovery
performance issue as the base backup ages, since they are included
in base backups, but not in WAL files.
 
http://archives.postgresql.org/pgsql-performance/2007-12/msg00203.php
 
> The operational question you need to ask yourself is: if
> you haven't swapped to the slave lately, how do you know it will work
> when you need it to?
 
Absolutely.  Nobody should ever assume they have a working backup
system without periodic tests that the backups can actually be used
to create a working system.  Ever.
 
-Kevin