At 15:25 10/08/00 -0700, Alfred Perlstein wrote:
>Before I run off and figure out how to syncronize a "backup" database
>with a live one, I was wondering if anyone had any pointers on
>implementing a delayed syncronization way of backing up a database
>while it's live. I'd really like to be able to only transfer over
>modified rows, rather than the entire database.
>
My *guess* is that the WAL should add a few options here - especially for
backup. However, if your replication is only partial, it may not help as much.
On other system I have used, you 'truncate' the WAL periodically and save
it is part of the backup. These pieces of WAL can be applied to a prior
copy of the database to produce a version of the DB at the time the WAL was
truncated.
Obviously this requires a little more than just the WAL, but it might be
the right way to go in the future for on-line backup and whole-database,
read-only replication.
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