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':

 LANGUAGE plpgsql
AS $function$
    create temp table tbl (id int) on commit drop;
    perform json_populate_record(null::tbl, '{ "id": 11 }'::json) as tt;

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?

Maksim Milyutin

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