Re: record identical operator

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От Kevin Grittner
Тема Re: record identical operator
Дата
Msg-id 1379367570.9782.YahooMailNeo@web162904.mail.bf1.yahoo.com
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Ответ на Re: record identical operator  (Andres Freund <andres@2ndquadrant.com>)
Ответы Re: record identical operator  (Andres Freund <andres@2ndquadrant.com>)
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Andres Freund <andres@2ndquadrant.com> wrote:
> On 2013-09-16 16:58:21 -0400, Noah Misch wrote:
>> memcmp() has served well for HOT and for _equalConst(); why
>> would it suddenly fall short for MV maintenance?
>
> I don't have a problem using it internally, I have a problem
> exposing the capability to sql.

... like we do in *pattern ops and the
suppress_redundant_updates_trigger() function?

> Don't tell me that's the same.

No, this gives users a way to make the same test that HOT uses for
whether values match, albeit undocumented.  Well, not exactly the
same test, because this patch detoasts before comparing -- but
pretty close.  The question is, if it's unsafe for a user to make
this test, why would it be safe for HOT to use it?

I'm really having trouble understanding what problem you have with
this.  Can you describe a scenario where someone shoots themselves
in the foot with it, because I'm not seeing any?

--
Kevin Grittner
EDB: http://www.enterprisedb.com
The Enterprise PostgreSQL Company



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