From: thomas at tada.se (Thomas Hallgren)
Date: Tue, 15 Aug 2006 00:53:17 +0200
Subject: [Pljava-dev] Notify/Listen
In-Reply-To: 
 <75F39425D1954A4380D5C9E1D630CDC903C30CB4@C2A007.stratford.auto.cooperintra.ctb>
References: 
 <75F39425D1954A4380D5C9E1D630CDC903C30CB4@C2A007.stratford.auto.cooperintra.ctb>
Message-ID: <44E0FEDD.7030005@tada.se>

Burtenshaw, John J. wrote:
> 
> Has anyone ever used the Notify/Listen mechanism in pljava?  How would 
> you implement a client program that would do an sql Listen?  Apparently 
> according to the Postgresql docs there are functions that need to be 
> called periodically to see if an event has occured or not (i.e. 
> PQnotifies in libpq)
> 
I doubt I can make LISTEN work in PL/Java. To my knowledge, there's no support for it in the 
underlying SPI routines and implementing such support would imply a multi-threaded backend.

Keep in mind that PL/Java executes functions within a transaction. It can never start a 
transaction on its own behalf. It is fundamentally different from a client.

Regards,
Thomas Hallgren