At 07:56 AM 9/5/02 +0200, Boguslaw Brandys wrote:

>
>As I understand You are talking about a journal to separate process (an
>later to an external file). This would be great for some replication schemma
>(one database is Master another - Slave like in MySQL) and if sources still
>exists in Firebird it is quite enought I think to build internal replication
>, so my idea would be worth not much. (IBReplicator exist but it is not Open
>Source and free as I know. Could it be based on journaling process You
>mention ?)

I suppose it could be used for physical replication, but a modest
extension to shadowing would be simpler and better. If you're
trying to maintain any sort of consistency, you need something
much smarter.

>I was thinking about something different : how to use existing feature of
>Interbase (record versioning) for avoid redo log completly.
>Unfortunately I don't know InterBase source quite well, I'm rather database
>manager and use InterBase as a programmer so maybe I misreported something.
>The idea was to sign each record (or each transaction in TIP - keep in mind
>that I don't know sources so I don't know what is better) with current
>server timestamp and don't let database engine to throw away old committed
>versions of record (as usual even without sweep) which timestamp is above
>some limit (for example Now() - 12 hours).
>This of course will cause database to grow fast (if this option is used) but
>allow to get snaphot of records below requested timestamp (so it is internal
>redo log).
>

Deferring record garbage collection would have a catastrophic effect
on performance on any volatile database. I trip through the archives
would probably spell out the details.

Jim Starkey