Christopher Browne wrote:
Centuries ago, Nostradamus foresaw when [EMAIL PROTECTED] ("Joshua D. Drake") would write:
I hope you understand that I, in no way have ever suggested
(purposely) anything negative about Slony. Only that I believe they
serve different technical solutions.

Stipulating that I may have some bias ;-), I still don't find it at
all clear what the different situations are "shaped like" that lead to
Mammoth being forcibly preferable to Slony-I.
I would choose replicator if:

1. You want ease of setup
2. You want your each transaction to be replicated at time of commit
3. Your database is already laden with triggers
4. You are pushing a very high transactional load*

* Caveat I have no idea how well Slony performs on a system that does say 200,000 transactions
an hours that are heavily geared toward updates. Replicator performs very well in this scenario.

5. Replicators administrative tools are more mature than Slony (for example you know exactly what state your slaves are in with Replicator).

I would choose Slony if:

1. The fact that it is Open Source matters to you
2. The auto promotion of slaves is important*

*This will be fixed in a couple of weeks with Replicator

To be fair, in the real world ---

It doesn't make a bit of difference which one you choose it really comes down to this:

Replicator is dumb simple to setup. Any halfway talented person can setup replicator
in 30 minutes with a single master / slave configuration.

Slony is Open Source and thus a little easier on the pocket book initially.

Command Prompt, will support either one -- so the Replicator is commercially supported
argument is a little weak here.


Joshua D. Drake


Joshua D. Drake

(Note that I have a pretty decent understanding about how ERS and
Slony work, so I'm not too frightened of technicalities...  I set up
instances of both on Thursday, so I'm pretty up to speed :-).)

Win32 support may be true at the moment, although I have to discount
that as we only just got the start of a beta release of native Win32
support for PostgreSQL proper.  For that very reason, I had to point
my youngest brother who needed "something better than Access" to
Firebird last Saturday; I played with my niece while he was doing the
install.  And there is little reason to think that Slony-I won't be
portable to Win32 given a little interest and effort, particularly
once work to make it play well with "pgxs" gets done.

Command Prompt, Inc., home of Mammoth PostgreSQL - S/ODBC and S/JDBC
Postgresql support, programming shared hosting and dedicated hosting.
+1-503-667-4564 - [EMAIL PROTECTED] -
PostgreSQL Replicator -- production quality replication for PostgreSQL

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