Re: delta relations in AFTER triggers

From: Robert Haas <robertmhaas(at)gmail(dot)com>
To: Kevin Grittner <kgrittn(at)ymail(dot)com>
Cc: David Fetter <david(at)fetter(dot)org>, Alvaro Herrera <alvherre(at)2ndquadrant(dot)com>, Pg Hackers <pgsql-hackers(at)postgresql(dot)org>
Subject: Re: delta relations in AFTER triggers
Date: 2014-06-30 15:03:06
Message-ID: CA+Tgmob2ARxaxYTOvq_owwrobgz2nJV59ffZWy=uCG+h6vdTpg@mail.gmail.com
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On Sat, Jun 28, 2014 at 10:35 AM, Kevin Grittner <kgrittn(at)ymail(dot)com> wrote:
> David Fetter <david(at)fetter(dot)org> wrote:
>> On Sat, Jun 21, 2014 at 11:06:26AM -0700, Kevin Grittner wrote:
>
>>> Here is v2.
>
>> I've taken the liberty of making an extension that uses this.
>> Preliminary tests indicate a 10x performance improvement over the
>> user-space hack I did that's similar in functionality.
>
> Wow, this goes well beyond what I expected for a review! Thanks!
>
> As I said in an earlier post, I think that this is best committed
> as a series of patches, one for the core portion and one for each
> PL which implements the ability to use the transition (delta)
> relations in AFTER triggers. Your extension covers the C trigger
> angle, and it seems to me to be worth committing to contrib as a
> sample of how to use this feature in C.
>
> It is very encouraging that you were able to use this without
> touching what I did in core, and that it runs 10x faster than the
> alternatives before the patch.
>
> Because this review advances the patch so far, it may be feasible
> to get it committed in this CF. I'll see what is needed to get
> there and maybe have a patch toward that end in a few days. The
> minimum that would require, IMV, is a plpgsql implementation,
> moving the new pg_trigger columns to the variable portion of the
> record so they can be null capable, more docs, and regression
> tests.

Not to rain on your parade, but this patch hasn't really had a serious
code review yet. Performance testing is good, but it's not the same
thing.

--
Robert Haas
EnterpriseDB: http://www.enterprisedb.com
The Enterprise PostgreSQL Company

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