Re: PATCH: Exclude unlogged tables from base backups

On 12/12/17 6:07 PM, Andres Freund wrote:
>>
>> I don't see this as any different than what happens during recovery. The
>> unlogged forks are cleaned / re-inited before replay starts which is the
>> same thing we are doing here.
> 
> It's quite different - in the recovery case there's no other write
> activity going on. But on a normally running cluster the persistence of
> existing tables can get changed, and oids can get recycled.  What
> guarantees that between the time you checked for the init fork the table
> hasn't been dropped, the oid reused and now a permanent relation is in
> its place?

Well, that's a good point!

How about rechecking the presence of the init fork after a main/other 
fork has been found?  Is it possible for an init fork to still be lying 
around after an oid has been recycled? Seems like it could be...

-- 
-David
david@pgmasters.net