On Wed, 2008-08-13 at 15:38 +0200, Markus Wanner wrote:
> Simon Riggs wrote:
> > Classification of Replication Techniques
>
> Thanks for your classifications. It helps a great deal to clarify.
>
> > Type 2 is where you ship the WAL (efficient) then use it to reconstruct
> > SQL (flexible) and then apply that to other nodes. It is somewhat harder
> > than type 1, but requires less infrastructure (IMHO). Definitely
> > requires less data shipping from Primary node, so very possibly more
> > efficient.
>
> What leads you to that conclusion? AFAICT a logical format, specifically
> designed for replication is quite certainly more compact than the WAL
> (assuming that's what you mean by "less data").
Possibly, but since we are generating and writing WAL anyway that's not
a completely fair comparison.
> Which of IBM's and Oracle's products are you referring to?
IBM DB2 HADR, QReplication.
Oracle Streams 10g+, Data Guard Logical and Physical Standby
All of which I've personally used, except for Oracle Streams10g, which I
investigated thoroughly for a client about 4 years ago.
-- Simon Riggs www.2ndQuadrant.comPostgreSQL Training, Services and Support
