On Fri, May 22, 2020 at 5:00 PM Rajkumar Raghuwanshi <
rajkumar.raghuwan...@enterprisedb.com> wrote:

> Hi All,
>
> I am getting ERROR when using the "FOR UPDATE" clause for the partitioned
> table. below is a reproducible test case for the same.
>
> CREATE TABLE tbl (c1 INT,c2 TEXT) PARTITION BY LIST (c1);
> CREATE TABLE tbl_null PARTITION OF tbl FOR VALUES IN (NULL);
> CREATE TABLE tbl_1 PARTITION OF tbl FOR VALUES IN (1,2,3);
>
> INSERT INTO tbl SELECT i,i FROM generate_series(1,3) i;
>
> CREATE OR REPLACE FUNCTION func(i int) RETURNS int
> AS $$
> DECLARE
>  v_var tbl%ROWTYPE;
>  cur CURSOR IS SELECT * FROM tbl WHERE c1< 5 FOR UPDATE;
> BEGIN
>  OPEN cur;
>  LOOP
>   FETCH cur INTO v_var;
>   EXIT WHEN NOT FOUND;
>   UPDATE tbl SET c2='aa' WHERE CURRENT OF cur;
>  END LOOP;
>  CLOSE cur;
>  RETURN 10;
> END;
> $$ LANGUAGE PLPGSQL;
>
> SELECT func(10);
>

I tried similar things on inherit partitioning as follow and that looks
fine:

DROP TABLE tbl;
CREATE TABLE tbl (c1 INT,c2 TEXT);
CREATE TABLE tbl_null(check (c1 is NULL)) INHERITS (tbl);
CREATE TABLE tbl_1 (check (c1 > 0 and c1 < 4)) INHERITS (tbl);
INSERT INTO tbl_1 VALUES(generate_series(1,3));

postgres=# SELECT func(10);
 func
------
   10
(1 row)

On looking further for declarative partition, I found that issue happens
only if
the partitioning pruning enabled, see this:

-- Execute on original set of test case.
postgres=# ALTER FUNCTION func SET enable_partition_pruning to off;
ALTER FUNCTION

postgres=# SELECT func(10);
 func
------
   10
(1 row)

I think we need some indication in execCurrentOf() to skip error if the
relation
is pruned.  Something like that we already doing for inheriting
partitioning,
see following comment execCurrentOf():

        /*
         * This table didn't produce the cursor's current row; some other
         * inheritance child of the same parent must have.  Signal caller to
         * do nothing on this table.
         */

Regards,
Amul

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