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Re: ROLLBACK triggers?

From: Stef T <stef(at)ummon(dot)com>
To: "Jonah H(dot) Harris" <jonah(dot)harris(at)gmail(dot)com>
Cc: Daisuke Maki <daisuke(at)wafu(dot)ne(dot)jp>, pgsql-hackers(at)postgresql(dot)org
Subject: Re: ROLLBACK triggers?
Date: 2006-01-23 17:30:59
Message-ID: 43D512D3.5@ummon.com (view raw or flat)
Thread:
Lists: pgsql-hackers
Hello Jonah,  
    Sorry for hi-jacking the thread (not my intent, I assure you)
however, is there any chance Jonah of expanding your work to include 'on
user login/logout' ?

    As an aside, a trigger on rollback seems... unlikely (at least to my
mind). What is the functionality if your rollback trigger fails ? Ugh.
Down that road I can see madness looming, however, this -is- monday so
... :)

    Regards
    Stef

Jonah H. Harris wrote:

> 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
> <mailto: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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> . 


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Subject: Re: ROLLBACK triggers?
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