Date: 2018-03-12 10:30:27 +0100
From: @PedroTadim
To: SQL devs <>
Version: -- development
CC: @njnes

Last updated: 2018-03-29 15:39:20 +0200

Comment 26252

Date: 2018-03-12 10:30:27 +0100
From: @PedroTadim

User-Agent: Mozilla/5.0 (X11; Linux x86_64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/65.0.3325.146 Safari/537.36
Build Identifier:

Infinite recursion happens in mserver in rel_reset_subquery call, leading to a stack overflow while optimizing the query bellow.

Reproducible: Always

Steps to Reproduce:

1. CREATE TABLE tab1(col0 INTEGER, col1 INTEGER, col2 INTEGER);
2. INSERT INTO tab1 VALUES(22,6,8), (28,57,45), (82,44,71);
3. SELECT DISTINCT + cor0.col1 / cor0.col1 col2 FROM tab1 AS cor0 GROUP BY col1 HAVING NOT NULL IN ( - col1 * cor0.col1 );

Actual Results:

Infinite recursion in rel_reset_subquery.

Expected Results:

An empty result set.

Backtrace:

0 0x00007fffe843ad85 in rel_reset_subquery (rel=0x7fffb4254950) at rel_optimizer.c:9281
1 0x00007fffe843ad8a in rel_reset_subquery (rel=0x7fffb4254950) at rel_optimizer.c:9281
2 0x00007fffe843ad8a in rel_reset_subquery (rel=0x7fffb4254950) at rel_optimizer.c:9281
.....

Comment 26254

Date: 2018-03-12 10:35:16 +0100
From: MonetDB Mercurial Repository <>

Changeset 5100acc0528d made by Pedro Ferreira pedro.ferreira@monetdbsolutions.com in the MonetDB repo, refers to this bug.

For complete details, see https//devmonetdborg/hg/MonetDB?cmd=changeset;node=5100acc0528d

Changeset description:

Added tests for bugs 6552 and 6553

Comment 26255

Date: 2018-03-13 10:13:40 +0100
From: @sjoerdmullender

The problem is that rel==rel->l so when rel_reset_subquery calls itself recursively on rel->l, it just repeats infinitely.

The assignment where rel->l is assigned the value rel is in rel_logical_value_exp where it says
if (outer)
outer->l = z;
because at this point, outer == *rel, left == *rel, and hence z == *rel (this is a different rel, *rel here is the same as the rel above).

Comment 26257

Date: 2018-03-14 10:03:52 +0100
From: MonetDB Mercurial Repository <>

Changeset 8c9f8c70fb25 made by Niels Nes niels@cwi.nl in the MonetDB repo, refers to this bug.

For complete details, see https//devmonetdborg/hg/MonetDB?cmd=changeset;node=8c9f8c70fb25

Changeset description:

fixed bugs 6552 and 6553, by more defensive code

Comment 26258

Date: 2018-03-14 10:04:05 +0100
From: @njnes

fixed crash

Comment 26319

Date: 2018-03-29 15:39:20 +0200
From: @sjoerdmullender

The Mar2018 version has been released.