PostgreSQL Replication

Hi,

I'm curious about how this replication thing works. I have read some articles and most of them was about Master-Multi Slave relation. Perhaps that's the primary use of replication, make everything in one server and see it's effects in every server. Also it's a performance optimization too. But, anyway, what about a Multi Master relation! I read that MySQL was giving a solution as MySQL Cluster but it's only recommended for LAN. And If you have a LAN there you wont need a multi master replication system a lot if you ask me (of course I understand that this is done to backup data, and also if one server goes down the other keep going but that's not the point and not my main question.)

What about I intend to make a system for WAN which are connected not via fiber optic cables but via internet! Is it recommended to use such a replication system. Because the replication will be very asynchronous (if the internet connection is low and if it isn't very stable) I guess. A little scenario to explain what I meant more clearly. Let's say we have two computers which one is at USA and other in UK. They are both master and both slave according to the data written. If you enter a data to UK, USA becomes the slave and replicate that data. And the same thing vice versa. Is it possible with PostgreSQL to build such a system. Will it be stable and secure. How much data loss can be guessed (but yes even 1bit can't be acceptable in such a case but I don't think this can occur as the data still exists in the other server.) What are possible problems that can occur. And also what about other databases (MSSQL,Oracle,DB2,MySQL)

It's not very easy to answer this question I think and maybe it does not fit to the novice section, but I dunno much about replication so I fit to this mailing group :) Anyway, I also welcome articles and other resources to read about this subject. (These articles can be about other databases too.)

Thank you for your time

Roy Simkes
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