> btw, can you publicly discuss how CommandPrompts  WAL-based
> replication works ? 

It's my company, if course I am ;)... but not in this thread. If you
are interested feel free to email me directly or start a new thread.

Good :)

Here come my questions :

>From looking at http://www.commandprompt.com/images/MR_components.jpg it
seems that you don't do replication just from WAL logs, but also collect
some extra info inside postgreSQL server. Is this so ?

If it is, then in what way does it differ from simple trigger-based
change logging ?

Do you make use of snapshot data, to make sure, what parts of WAL log
are worth migrating to slaves , or do you just apply everything in WAL
in separate transactions and abort if you find out that original
transaction aborted ?

Are your slaves a) standby b) read-only or c) read-write ?

Do you extract / generate full sql DML queries from data in WAL logs, or
do you apply the changes at some lower level ?

For what use cases do you think your WAL-based approach is better than
Slony/Skytools trigger-based one ?


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