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Re: BUG #5776: Unable to create view with parameter in PL/pgsql

From: "Andrey G(dot)" <andvgal(at)gmail(dot)com>
To: Pavel Stehule <pavel(dot)stehule(at)gmail(dot)com>
Cc: Robert Haas <robertmhaas(at)gmail(dot)com>, pgsql-bugs(at)postgresql(dot)org
Subject: Re: BUG #5776: Unable to create view with parameter in PL/pgsql
Date: 2010-12-14 17:18:43
Message-ID: AANLkTikiadobBLC3qNWDb8=rqiZ8hr4hfFT3DXoogkRc@mail.gmail.com (view raw or flat)
Thread:
Lists: pgsql-bugs
OK.

Thanks,
Andrey.



2010/12/14 Pavel Stehule <pavel(dot)stehule(at)gmail(dot)com>:
> Hello
>
> 2010/12/14 Andrey G. <andvgal(at)gmail(dot)com>:
>> Pavel,
>>
>> As far as I'm aware, SETOF return creates whole result in memory, what
>> has some implications.
>>
>
> it's not true for immutable SQL function - look on EXPLAIN
>
>> My intention was to create a temporary view in session, which can be
>> used in other processing. Of course, I've found another solution, but
>> creating view with parameter dynamically could be a good feature.
>>
>
> It's done - SQL immutable function works exactly like you need.
>
> Regards
>
> Pavel Stehule
>
>
>> Andrey
>>
>>
>>
>> 2010/12/14 Pavel Stehule <pavel(dot)stehule(at)gmail(dot)com>:
>>> Hello
>>>
>>> View must not has a parameter in PostgreSQL. You can use a SRF function:
>>>
>>> postgres=# create or replace function parametrized_view(a int)
>>>                  returns setof foo as $$
>>>                     select * from foo where a = $1;
>>>                  $$ language sql immutable;
>>> CREATE FUNCTION
>>> postgres=# select * from parametrized_view(10);
>>>  a
>>> ----
>>>  10
>>> (1 row)
>>>
>>> postgres=# explain select * from parametrized_view(10);
>>>                          QUERY PLAN
>>> --------------------------------------------------------------
>>>  Index Scan using aa on foo  (cost=0.00..8.27 rows=1 width=4)
>>>   Index Cond: (a = 10)
>>> (2 rows)
>>>
>>> Regards
>>>
>>> Pavel Stehule
>>>
>>>
>>> 2010/12/13 Andrey G. <andvgal(at)gmail(dot)com>:
>>>> It seems my original test, which also includes the EXECUTE approach,
>>>> has not come to you in full. EXECUTE statement also fails with
>>>> parameter: The test is attached in file.
>>>>
>>>> psql -q < db/db/pgbug_5776.sql
>>>> ERROR:  there is no parameter $1
>>>> LINE 1: CREATE VIEW v4 AS SELECT * FROM t1 WHERE some_field = $1
>>>>                                                               ^
>>>> QUERY:  CREATE VIEW v4 AS SELECT * FROM t1 WHERE some_field = $1
>>>> CONTEXT:  PL/pgSQL function "bug_create_tmp_view_exec_test" line 3 at
>>>> EXECUTE statement
>>>>
>>>> Andrey
>>>>
>>>>
>>>> 2010/12/13 Robert Haas <robertmhaas(at)gmail(dot)com>
>>>>>
>>>>> On Tue, Nov 30, 2010 at 4:43 PM, Andrey Galkin <andvgal(at)gmail(dot)com> wrote:
>>>>> >
>>>>> > The following bug has been logged online:
>>>>> >
>>>>> > Bug reference:      5776
>>>>> > Logged by:          Andrey Galkin
>>>>> > Email address:      andvgal(at)gmail(dot)com
>>>>> > PostgreSQL version: 9.0.1
>>>>> > Operating system:   Debian unstable
>>>>> > Description:        Unable to create view with parameter in PL/pgsql
>>>>> > Details:
>>>>> >
>>>>> > Below is simple test case. Perhaps, I'm doing something wrong.
>>>>>
>>>>> You can accomplish what you're trying to do using EXECUTE.
>>>>>
>>>>> --
>>>>> Robert Haas
>>>>> EnterpriseDB: http://www.enterprisedb.com
>>>>> The Enterprise PostgreSQL Company
>>>>
>>>>
>>>> --
>>>> Sent via pgsql-bugs mailing list (pgsql-bugs(at)postgresql(dot)org)
>>>> To make changes to your subscription:
>>>> http://www.postgresql.org/mailpref/pgsql-bugs
>>>>
>>>>
>>>
>>
>

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