Re: why copy tuple in the end of trigger when nothing changed in NEW OLD record variable

From: "billy" <billywq(at)163(dot)com>
To: pgsql-hackers(at)postgresql(dot)org <pgsql-hackers(at)postgresql(dot)org>
Subject: Re: why copy tuple in the end of trigger when nothing changed in NEW OLD record variable
Date: 2008-06-11 04:57:15
Message-ID: 484F5B47.0460FE.04501@m12-15.163.com
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Tom Lane,

er, your explanation is reasonable.

But at least the comment
if (newtuple != tuple) /* modified by Trigger(s) */
{
.....
is likely to misdirect us.

It took me a few hours to figure it out. :-(

======= 2008-06-10 23:43:00 In your letter you say:=======

>"billy" <billywq(at)163(dot)com> writes:
>> I think we can add some judgment conditions in function plpgsql_exec_trigger() to avoid this problem.
>
>I don't especially see the point of adding extra complexity here.
>AFAICS you are talking about avoiding one or two palloc/pfree
>cycles, which is surely down in the noise compared to the cost of
>calling a plpgsql trigger.
>
> regards, tom lane
>
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        billy
        billywq(at)163(dot)com
          2008-06-11

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