Date: 2016-11-09 10:57:40 +0100
From: Dean De Leo <>
To: SQL devs <>
Version: -- development
CC: @njnes

Last updated: 2016-12-21 13:07:44 +0100

Comment 24654

Date: 2016-11-09 10:57:40 +0100
From: Dean De Leo <>

User-Agent: Mozilla/5.0 (X11; Fedora; Linux x86_64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/54.0.2840.71 Safari/537.36
Build Identifier:

The server crashes due to a null pointer unexpected in the query rewriter.

On Linux, tip of the default branch, debug build, empty tables.

Reproducible: Always

Steps to Reproduce:

1. Load the schema.sql
2. Issue query1a.sql
3. boom

Actual Results:

The DBMS crashes with a segmentation fault, see backtrace1.txt

Expected Results:

Server failures are bad. Assuming they should never occur.

Comment 24655

Date: 2016-11-09 10:58:27 +0100
From: Dean De Leo <>

Created attachment 492
Database schema

Attached file: schema.sql (application/sql, 7731 bytes)
Description: Database schema

Comment 24656

Date: 2016-11-09 10:59:01 +0100
From: Dean De Leo <>

Created attachment 493
Query (query1a.sql)

Attached file: query1a.sql (application/sql, 1393 bytes)
Description: Query (query1a.sql)

Comment 24657

Date: 2016-11-09 10:59:26 +0100
From: Dean De Leo <>

Created attachment 494
Back trace from the debugger

Attached file: backtrace1.txt (text/plain, 5120 bytes)
Description: Back trace from the debugger

Comment 24670

Date: 2016-11-09 23:07:04 +0100
From: MonetDB Mercurial Repository <>

Changeset bfc05edc1fa1 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=bfc05edc1fa1

Changeset description:

fixes for bugs 6114, 6115, 6116 and 6117

improved dead code elimination for cases with references to sub queries (ie its a dag)
push simple select like expressions downs

split_project test is added here but only crashes in the dec2016/default.

Comment 24674

Date: 2016-11-10 08:04:38 +0100
From: @njnes

fixed a problem with dead code elimination