On 26.09.2017 23:25, Maksim Milyutin wrote:
25.09.17 20:50, Maksim Milyutin wrote:
I have found out the problem when try to sequentially call the
function that casts constant to composite type of temporary table
that is deleted ateach transaction termination (i.e. at each function
call completion).
For example, we have the following function 'test':
CREATE OR REPLACE FUNCTION test()
RETURNS void
LANGUAGE plpgsql
AS $function$
begin
create temp table tbl (id int) on commit drop;
perform json_populate_record(null::tbl, '{ "id": 11 }'::json) as tt;
end;
$function$
Оn the second and subsequent calls we'll observe the following error:
ERROR: cache lookup failed for type 16392
I investigated the problem and realized that result type of function
*json_populate_record* (/funcresulttype/ field of /FuncExpr/ struct)
as well as type of the first null argument (/consttype/ field of
/Const/ struct) refer to the invalid composite type related with
temporary table'tbl'. Namely they take a value of oid gotten from the
first 'tbl' initialization. The plan of query *'perform
json_populate_record(null::tbl, '{ "id": 11 }'::json) as tt'*is
cached and is not invalidated at each function call. This is
because** the statement of this query doesn't have any dependency
from the 'tbl' relation (/relationOids/ list of /CachedPlanSource/
struct).
Attached patch resolves this problem by adding dependency from
relation upon detection Const expression of composite type of that
relation
Updated patchset contains more transparent definition of composite
type for constant node and regression test for described above buggy case.
Is there any interest on the problem in this thread?
--
Regards,
Maksim Milyutin
