Re[2]: [GENERAL] Rйp

Martijn!

Tuesday, October 08, 2002, 3:45:13 PM, you wrote:

>>  -  No, PostgreSQL does NOT provide a way to restore a database up to the
>> last commited transaction, with a reapply of the WAL, as Oracle or SQL
>> Server ( and others, I guess) do. That would be a VERY good feature. See
>> Administrator's guide ch11

MvO> Umm, I thought the whole point of WAL was that if the database crashed, the
MvO> WAL would provide the info to replay to the last committed transaction.

MvO> http://www.postgresql.org/idocs/index.php?wal.html

MvO> ... because we know that in the event of a crash we will be able to recover
MvO> the database using the log: ...

MvO> These docs seem to corrobrate this.

>> So, with Pg, if you backup your db every night with pg_dump, and your
>> server crashes during the day, you will loose up to one day of work.

MvO> I've never lost any data with postgres, even if it's crashed, even without
MvO> WAL.

Suppose you made your nightly backup, and then after a day of work
the building where your server is located disappears in flames..

That's it - you lost one day of work (of course, if your dumps where
stored outside that building otherwise you lost everything)..

There is a need in "incremental" backup, which backs up only those
transactions which has been fulfilled after last "full dump" or last
"incremental dump".  These backups should be done quite painlessly -
just copy some part of WAL, and should be small enough (compared to
full dump), so they can be done each hour or even more frequently..

I hope sometime PostgreSQL will support that. :-)

Sincerely Yours,
Timur
mailto:itvthor@sdf.lonestar.org