Re: ROLLBACK triggers?

Daisuke,

A patch was done for replication hooks which implements global
database-level triggers for connection startup and shutdown, and transaction
begin, commit, and rollback; they may help you out in this situation.

http://gorda.di.uminho.pt/community/pgsqlhooks/

-Jonah

On 1/23/06, Daisuke Maki <daisuke(at)wafu(dot)ne(dot)jp> wrote:
>
> Hi,
>
> First, apologies if my question is a bit off-course. Please feel free to
> direct me to a different mailing list if not appropriate.
>
> I'm currently trying to embed Senna full text search engine
> (http://qwik.jp/senna/) into postgres. I'm trying to achieve this by
> using triggers (implemented in C) to cause an update to senna's index at
> various points.
>
> This seemed to work fine until I realized that while postgres' SQL
> commands could be rolled back, Senna's index remained already-changed.
> There are other potential issues with regards to transaction safety, but
> currently this seems to be a problem that I cannot fix by simply
> patching Senna. So I thought that if there was a rollback trigger, I
> could call whatever necessary to undo the changes that were made to the
> index.
>
> A quick scan of the docs and the source code tree seems to indicate that
> there is no such thing as a rollback trigger, short of hacking it.
>
> Now, I'm wondering:
> 1. Is there a rollback/commit trigger? If not, is it planned to be
> implemented at all?
> 2. Is there a way to undo changes to data external to postgres
> when a rollback occurs, OR, only update that external data
> when a commit occurs?
>
> Thanks in advance,
> --d
>
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