From: Markus Schiltknecht <markus@bluegap.ch>
Subject: Re: standard interfaces for replication providers
Date: Tue, 08 Aug 2006 18:08:52 +0000
Organization: Hub.Org Networking Services
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	<200608041733.24228.jop@lsd.di.uminho.pt>
	<44D70EDA.9060602@bluegap.ch>
	<200608071940.26750.jop@lsd.di.uminho.pt>
	<44D89EA5.5090703@bluegap.ch> <87irl3uqgx.fsf@wolfe.cbbrowne.com>
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To: Christopher Browne <cbbrowne@acm.org>
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In-Reply-To: <87irl3uqgx.fsf@wolfe.cbbrowne.com>
To: pgsql-hackers@postgresql.org

Hello Christopher,

Christopher Browne wrote:
> Most databases that are interesting to replicate are implemented in C
> or C++, thereby implying that a suitably "deep" API needs to be
> implemented in C.

I generally agree with you. Although it's probably worth mentioning that 
the API they propose adds hooks to PostgreSQL in the form of triggers. 
This API comes as a patch is against the PostgreSQL source, thus in C.

The nature of triggers in PostgreSQL would then allow to write 
replication systems in whatever language you prefer, as long as there is 
a PL/{$LANG} for $LANG = your favorite.

I'm questioning if a replication system can be written by only using 
triggers as hooks. AFAIK Slony-I uses triggers, so you can probably 
better comment on problems or limitations using triggers. For me a 
shared library with some hooks as C function calls seems a more 
plausible approach.

Regards

Markus