From: | Heikki Linnakangas <heikki(dot)linnakangas(at)enterprisedb(dot)com> |
---|---|
To: | Alvaro Herrera <alvherre(at)commandprompt(dot)com> |
Cc: | Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us>, Stefan Kaltenbrunner <stefan(at)kaltenbrunner(dot)cc>, Stefan Huehner <stefan(at)huehner(dot)org>, pgsql-bugs(at)postgresql(dot)org |
Subject: | Re: Bug (8.4beta): FailedAssertion("!(bms_is_subset(relids, qualscope))", File: "initsplan.c", Line: 915) |
Date: | 2009-05-06 17:45:05 |
Message-ID: | 4A01CCA1.405@enterprisedb.com |
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Lists: | pgsql-bugs |
Alvaro Herrera wrote:
> Tom Lane wrote:
>
>> Oh! What is happening is that to_number(1) is being reduced to constant
>> NULL, whereupon it concludes that ad_tab_id=to_number(1) is constant
>> NULL, ergo the EXISTS can never succeed, ergo the entire WHERE is
>> constant false.
>
>> CREATE FUNCTION to_number(integer) RETURNS numeric
>> LANGUAGE plpgsql IMMUTABLE
>> AS $_$
>> BEGIN
>> RETURN to_number($1, 'S99999999999999D999999');
>> EXCEPTION
>> WHEN OTHERS THEN
>> RETURN NULL;
>> END;
>> $_$;
>
> How can the executor "see through" a plpgsql function definition? Or do
> you mean that this reduction is being done at execution time? (hmm ...
> this is what a one-time filter is, now that I think about it?)
Note that the function is immutable, and the argument in the query is a
constant. The planner simply runs the function and replaces the function
call with the result.
--
Heikki Linnakangas
EnterpriseDB http://www.enterprisedb.com
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Next Message | Alvaro Herrera | 2009-05-06 17:48:32 | Re: Bug (8.4beta): FailedAssertion("!(bms_is_subset(relids, qualscope))", File: "initsplan.c", Line: 915) |
Previous Message | Alvaro Herrera | 2009-05-06 17:38:51 | Re: Bug (8.4beta): FailedAssertion("!(bms_is_subset(relids, qualscope))", File: "initsplan.c", Line: 915) |