Re: some last patches breaks plan cache

On 03/31/2018 07:56 PM, Tomas Vondra wrote:
> On 03/31/2018 07:38 PM, Pavel Stehule wrote:
>> Hi
>>
>> CREATE OR REPLACE PROCEDURE public.proc(a integer, INOUT b integer, c
>> integer)
>>  LANGUAGE plpgsql
>> AS $procedure$
>> begin
>>   b := a + c;
>> end;
>> $procedure$
>>
>> CREATE OR REPLACE PROCEDURE public.testproc()
>>  LANGUAGE plpgsql
>> AS $procedure$
>> declare r int;
>> begin
>>   call proc(10, r, 20);
>> end;
>> $procedure$
>>
>> postgres=# call testproc();
>> CALL
>> postgres=# call testproc();
>> ERROR:  SPI_execute_plan_with_paramlist failed executing query "CALL
>> proc(10, r, 20)": SPI_ERROR_ARGUMENT
>> CONTEXT:  PL/pgSQL function testproc() line 4 at CALL
>> postgres=#
>>
>> second call fails
>
> Yeah.
>
> d92bc83c48bdea9888e64cf1e2edbac9693099c9 seems to have broken this :-/
>

FWIW it seems the issue is somewhere in exec_stmt_call, which does this:

/*
* Don't save the plan if not in atomic context. Otherwise,
* transaction ends would cause warnings about plan leaks.
*/
exec_prepare_plan(estate, expr, 0, estate->atomic);

When executed outside transaction, CALL has estate->atomic=false, and so
calls exec_prepare_plan() with keepplan=false. And on the second call it
gets bogus Plan, of course (with the usual 0x7f7f7f7f7f7f7f7f patterns).

When in a transaction, it sets keepplan=true, and everything works fine.

So either estate->atomic is not sufficient on it's own, or we need to
reset the expr->plan somewhere.

regards

--
Tomas Vondra http://www.2ndQuadrant.com
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