Re: Oracle Snapshots

beumerh_at_cts.com (Hal Beumer) wrote:

>In article <46ipd3$7qi_at_info1.sdrc.com> "Dana M. Riley" <dmriley> writes:
 

>>I have an application where, for performance reasons, I would like to
>>replicate a read-only copy of a database overseas. The initial database
>>is approximately 1GByte with approximately 250KB/Day of additions and/or
>>modifications. I am considering using Snapshots for this application.
>>I have two questions. How well do snapshots work with Oracle 7.1.6? (I
>>had been told that snapshots did not work well in 7.0.?)

There is an important addition to Snapshots in 7.1.6 (apart from Symmetric Replication). Up to 7.1.5, the unit of replication was the table - that is 1 table per transaction. This is fine for many applications, but if replicating groups of related tables, several transactions would be involved. 7.1.6 introduces Snapshot Groups so that multiple tables can be replicated in a single transaction.

>Snapshot Replication appeared in Oracle 7.1.4. Oracle 7.1.6 supports N-way and
>updateable snapshots also using the distributed option. Snapshots work
>fine.

Not quite correct- snapshots have been around since 7.0, and N-way/updatable snapshots are part of the Advanced Replication option. The distributed option gives two phase commit and snapshots only.

Cheers,

Dave Received on Tue Nov 07 1995 - 00:00:00 CET