See archives of this mailing list.
WAL is write-ahead logging, more conventional way of assuring atomicity.
(I.E. before a transaction is written to database, it is written to
transaction log, which can be replayed). Replication can be achieved by
streaming transaction log toyour replicated computer which will apply to
its own database.
I think its scheduled for postgresql 7.2...
On Wed, 31 May 2000, Mihai Gheorghiu wrote:
> Thanks a lot.
> Now, what is WAL?
> When is it scheduled for implementation?
>
>
> >It means Postgres can do a reliable backup (a consistent snapshot) of a
> >database without shutting down the database.
> >
> >What you are asking for is replication, which is not easy to implement,
> >and almost damn impossible to get it RIGHT. (*curse at both Sybase and
> >Oracle replication servers*). (i.e. how do you resolve replication
> >conflicts, how do you resync databases for which you don't have
> >transaction logs, etc). I assume for Postgres, replication is a
> >possibility after WAL is implemented...
> >
> >On Tue, 30 May 2000, Mihai Gheorghiu wrote:
> >
> >> http://networkdna.com/database/index.html mentions that PostgreSQL is
> >> capable of "Online backup". What does that exactly mean?
> >> I'd like to be able to run a synchronization (in MS Access terms) (or
> >> "incremental backup"???), i.e. to have two databases in two locations,
> >> normally using only one of them and updating the other one. (Normal full
> >> backup looks unrealistic for 300MB over 1/3 of a T1.) In case the
> >> communication line between the two centers fails, users at the two ends
> >> should be able to use the local databases, and changes made during
> >> communication downtime be appended to the other database after
> communication
> >> resume.
> >
>
>
