Обсуждение: About Redo

Hello,

I want to know the use of the transaction files in "pg_xlog".
My concern is REDO such as ORACLE do.
The following is our recovery method. I don't know whether it's possible
or not.

1. Stop DB.
2. Clear the transaction files.
3. Save the directory "data" by tar command.
4. Start DB.
:
Something is wrong and decide to recover.
:
5. Stop DB.
6. Remove new DB except the transaction files.
7. Copy back old DB.
8. And REDO. (But how?)

The tables or indexes are not created.
(At the begining of the system, all are created.)

Best regards,

No. The WAL files do not contain data to redo everything which was
done to the database since day X. The WAL files contain data of
current active transactions. In case the transaction aborts, the
database will be returned to the stage it was in before the
transaction started (aka Before Imaging). The scenario you are
describing is sometimes called After Imaging and as far as I know, it
is not (yet) implemented in PostgreSQL.

Best regards,
Chris


At 02:51 +0900 02/14/2002, Osamu Ninagi wrote:
>Hello,
>
>I want to know the use of the transaction files in "pg_xlog".
>My concern is REDO such as ORACLE do.
>The following is our recovery method. I don't know whether it's possible
>or not.
[snip]

--
Chris Ruprecht
Network grunt and bit pusher extraordinaíre

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