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Thread: PL argument max size, and doubt

PL argument max size, and doubt

From
Martin Marques
Date:
I was doing some tests to see if I could find a max size for an argument
of type TEXT in a PL/PgSQL function (BTW, which it that limit if it
exists?).

So I made the function to test:

CREATE OR REPLACE FUNCTION datoGrande(TEXT) RETURNS BOOLEAN AS $body$
BEGIN
EXECUTE $ins1$
INSERT INTO funcdatogrande VALUES (default,$ins1$ ||     quote_literal($1) || $ins2$)$ins2$;
IF FOUND THEN
RETURN TRUE;
ELSE
RETURN FALSE;
END IF;
END;
$body$ LANGUAGE 'plpgsql';


What bothers me is that the INSERT passes ok (the data is inserted) but
the function is returning false on any all to it. I hope not to have a
conceptual problem.

Re: PL argument max size, and doubt

From
"Rodrigo De León"
Date:
On Nov 21, 2007 8:23 AM, Martin Marques <martin@marquesminen.com.ar> wrote:
> (BTW, which it that limit if it exists?).

"In any case, the longest possible character string that can be stored
is about 1 GB."

See:
http://www.postgresql.org/docs/8.2/static/datatype-character.html

> So I made the function to test:
>
> CREATE OR REPLACE FUNCTION datoGrande(TEXT) RETURNS BOOLEAN AS $body$
> BEGIN
> EXECUTE $ins1$
> INSERT INTO funcdatogrande VALUES (default,$ins1$ ||
>                  quote_literal($1) || $ins2$)$ins2$;
> IF FOUND THEN
> RETURN TRUE;
> ELSE
> RETURN FALSE;
> END IF;
> END;
> $body$ LANGUAGE 'plpgsql';
>
>
> What bothers me is that the INSERT passes ok (the data is inserted) but
> the function is returning false on any all to it. I hope not to have a
> conceptual problem.

I don't think EXECUTEing sets FOUND to true. Try:

CREATE OR REPLACE FUNCTION DATOGRANDE(TEXT)
RETURNS BOOLEAN AS $$
BEGIN INSERT INTO FUNCDATOGRANDE VALUES (DEFAULT,$1); IF FOUND THEN   RETURN TRUE; ELSE   RETURN FALSE; END IF;
END;
$$ LANGUAGE 'PLPGSQL';

Re: PL argument max size, and doubt

From
Martin Marques
Date:
Rodrigo De León escribió:
> On Nov 21, 2007 8:23 AM, Martin Marques <martin@marquesminen.com.ar> wrote:
>   
>> (BTW, which it that limit if it exists?).
>>     
>
> "In any case, the longest possible character string that can be stored
> is about 1 GB."
>
> See:
> http://www.postgresql.org/docs/8.2/static/datatype-character.html
>   
I was asking about the limit in the argument. Is it the same as the 
limits the types have in table definition?

>> So I made the function to test:
>>
>> CREATE OR REPLACE FUNCTION datoGrande(TEXT) RETURNS BOOLEAN AS $body$
>> BEGIN
>> EXECUTE $ins1$
>> INSERT INTO funcdatogrande VALUES (default,$ins1$ ||
>>                  quote_literal($1) || $ins2$)$ins2$;
>> IF FOUND THEN
>> RETURN TRUE;
>> ELSE
>> RETURN FALSE;
>> END IF;
>> END;
>> $body$ LANGUAGE 'plpgsql';
>>
>>
>> What bothers me is that the INSERT passes ok (the data is inserted) but
>> the function is returning false on any all to it. I hope not to have a
>> conceptual problem.
>>     
>
> I don't think EXECUTEing sets FOUND to true. Try:
>
> CREATE OR REPLACE FUNCTION
>   DATOGRANDE(TEXT)
> RETURNS BOOLEAN AS $$
> BEGIN
>   INSERT INTO FUNCDATOGRANDE VALUES (DEFAULT,$1);
>   IF FOUND THEN
>     RETURN TRUE;
>   ELSE
>     RETURN FALSE;
>   END IF;
> END;
> $$ LANGUAGE 'PLPGSQL';
>   

I have always heard that modification queries should be EXECUTED in PL. 
AFAICR.

Re: PL argument max size, and doubt

From
Tom Lane
Date:
Martin Marques <martin@marquesminen.com.ar> writes:
> Rodrigo De León escribió:
>> "In any case, the longest possible character string that can be stored
>> is about 1 GB."
>> 
> I was asking about the limit in the argument. Is it the same as the 
> limits the types have in table definition?

Yeah, ultimately this is a palloc() restriction on the size of any one
data value.

> I have always heard that modification queries should be EXECUTED in PL. 
> AFAICR.

Run far away from whatever source gave you that advice...
        regards, tom lane

Re: PL argument max size, and doubt

From
Martin Marques
Date:
Tom Lane escribió:
> Martin Marques <martin@marquesminen.com.ar> writes:
> 
>> I have always heard that modification queries should be EXECUTED in PL. 
>> AFAICR.
> 
> Run far away from whatever source gave you that advice...

Sorry, it was with DDL commands.

Re: PL argument max size, and doubt

From
Tom Lane
Date:
Martin Marques <martin@marquesminen.com.ar> writes:
> Tom Lane escribió:
>> Martin Marques <martin@marquesminen.com.ar> writes:
>>> I have always heard that modification queries should be EXECUTED in PL. 
>>> AFAICR.
>> 
>> Run far away from whatever source gave you that advice...

> Sorry, it was with DDL commands.

That's not much better ;-).  DDL commands don't have plans, so there's
not anything that could be invalidated.  I don't see any reason to use
an EXECUTE unless there's an actual textual change in the command you
need to execute.
        regards, tom lane

Re: PL argument max size, and doubt

From
Martin Marques
Date:
Tom Lane escribió:
> Martin Marques <martin@marquesminen.com.ar> writes:
>> Tom Lane escribió:
>>> Martin Marques <martin@marquesminen.com.ar> writes:
>>>> I have always heard that modification queries should be EXECUTED in PL. 
>>>> AFAICR.
>>> Run far away from whatever source gave you that advice...
> 
>> Sorry, it was with DDL commands.
> 
> That's not much better ;-).  DDL commands don't have plans, so there's
> not anything that could be invalidated.  I don't see any reason to use
> an EXECUTE unless there's an actual textual change in the command you
> need to execute.

Well, actually....

http://archives.postgresql.org/pgsql-sql/2007-02/msg00214.php

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