Simple recursion function on plpgsql - Postgresql 7.1

From: "Vadim I(dot) Passynkov" <pvi(at)axxent(dot)ca>
To: "pgsql-bugs(at)postgresql(dot)org" <pgsql-bugs(at)postgresql(dot)org>
Subject: Simple recursion function on plpgsql - Postgresql 7.1
Date: 2001-07-04 17:26:36
Message-ID: 3B4351CC.8D6BA03D@axxent.ca
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Hi All

Simple task: calculate number children for parent 1
1
/|\
7 2 8
/ \
3 4
/ \
5 6

DROP TABLE test1;
CREATE TABLE test1 ( child int4, parent int4 );

INSERT INTO test1 VALUES ( 2, 1 );
INSERT INTO test1 VALUES ( 7, 1 );
INSERT INTO test1 VALUES ( 8, 1 );

INSERT INTO test1 VALUES ( 3, 2 );
INSERT INTO test1 VALUES ( 4, 2 );

INSERT INTO test1 VALUES ( 5, 4 );
INSERT INTO test1 VALUES ( 6, 4 );

DROP FUNCTION test1 ( int4, int2 );
CREATE FUNCTION test1 ( int4, int2 ) RETURNS int4 AS '
DECLARE
rec record;
cn int4;
BEGIN
IF $2 = 100 THEN
RAISE EXCEPTION ''Loop !!!'';
END IF;
cn := ( SELECT COUNT ( * ) FROM test1 WHERE parent = $1 );
FOR rec IN SELECT child FROM test1 WHERE parent = $1 LOOP
cn := test1 ( rec.child, $2 + 1 ) + cn;
END LOOP;
RETURN cn;
END;
' LANGUAGE 'plpgsql';

SELECT test1 ( 1, 0 );
test1
-------
7
(1 row)

This result is OK.

but if in test1 function replace string
"cn := test1 ( rec.child, $2 + 1 ) + cn;"
to
"cn := cn + test1 ( rec.child, $2 + 1 );"

SELECT test1 ( 1, 0 );
test1
-------
6

Very strange problem;
On 7.0.3 both functions working right.

--

Vadim I. Passynkov, Axxent Corp.
mailto:pvi(at)axxent(dot)ca

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