Re: Implementing incremental backup

> * Tatsuo Ishii (ishii@postgresql.org) wrote:
>> > * Tatsuo Ishii (ishii@postgresql.org) wrote:
>> >> Yeah, at first I thought using WAL was a good idea.  However I realized
>> >> that the problem using WAL is we cannot backup unlogged tables because
>> >> they are not written to WAL.
>> > 
>> > Unlogged tables are also nuked on recovery, so I'm not sure why you
>> > think an incremental backup would help..  If you're recovering (even
>> > from a simple crash), unlogged tables are going to go away.
>> 
>> If my memory serves, unlogged tables are not nuked when PostgeSQL is
>> stopped by a planned shutdown (not by crash or by "pg_ctl -m i
>> stop"). If PostgreSQL works so, incremental backup should be able to
>> recover unlogged tables as well, at least people would expect so IMO.
> 
> Sure, if you shut down PG, rsync the entire thing and then bring it back
> up then unlogged tables should work when "backed up".

I don't think using rsync (or tar or whatever general file utils)
against TB database for incremental backup is practical. If it's
practical, I would never propose my idea.

> They're not WAL'd, so expecting them to work when restoring a backup of
> a PG that had been running at the time of the backup is folly.

Probably you forget about our nice pg_dump tool:-)
--
Tatsuo Ishii
SRA OSS, Inc. Japan
English: http://www.sraoss.co.jp/index_en.php
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