Assertion failure in rel_bin.c:2548: rel2bin_groupby: Assertion `0' failed.

[monetdb-team]

Date: 2015-05-11 15:45:50 +0200
From: Richard Hughes <<richard.monetdb>>
To: SQL devs <>
Version: 11.19.11 (Oct2014-SP3)
CC: @njnes

Last updated: 2015-06-22 22:32:22 +0200

Comment 20860

Date: 2015-05-11 15:45:50 +0200
From: Richard Hughes <<richard.monetdb>>

To reproduce:
sql>create table foo (a int);
sql>select b from(select 1,1=1,1,1,1 from foo union all select 1,null,1,1,1)as t(a,b,c,d,e);

Expected result:
null

Actual result:
mserver5: rel_bin.c:2548: rel2bin_groupby: Assertion `0' failed.
Aborted

That seems to be the simplest I can get the query. Removing some of those apparently-superfluous columns stops the assertion.

This used to work. Bisected to:
changeset: 55349:c891240ec139
branch: Oct2014
user: Niels Nes niels@cwi.nl
date: Sun Apr 19 21:50:46 2015 +0200
summary: on project rewrite check if the rewriten project expression
http://dev.monetdb.org/hg/MonetDB/rev/c891240ec139

Comment 20863

Date: 2015-05-13 15:28:43 +0200
From: @njnes

fixed, added missing reset of a hash table after relational rewrites (renames).

Comment 20864

Date: 2015-05-13 16:49:14 +0200
From: MonetDB Mercurial Repository <>

Changeset 0b63993ab0ed made by Niels Nes niels@cwi.nl in the MonetDB repo, refers to this bug.

For complete details, see http//devmonetdborg/hg/MonetDB?cmd=changeset;node=0b63993ab0ed

Changeset description:

added test for bug #3723

Comment 20865

Date: 2015-05-13 16:49:19 +0200
From: MonetDB Mercurial Repository <>

Changeset 3030f18c2fc0 made by Niels Nes niels@cwi.nl in the MonetDB repo, refers to this bug.

For complete details, see http//devmonetdborg/hg/MonetDB?cmd=changeset;node=3030f18c2fc0

Changeset description:

fixed bug #3723 (cleanup hash after renaming expressions)