MIN/MAX of a UUID column produces wrong results

[monetdb-team]

Date: 2016-03-14 18:20:15 +0100
From: @yzchang
To: SQL devs <>
Version: 11.21.13 (Jul2015-SP2)

Last updated: 2016-03-25 09:59:27 +0100

Comment 21902

Date: 2016-03-14 18:20:15 +0100
From: @yzchang

Created attachment 389
CSV data to populate the table

The csv file is attached. Unpack and save it in /tmp directory. Then, with the queries below, the MIN/MAX values returned are wrong in two ways:

1. the values don't exist in the CSV data
2. seemly random, and different values are returned by every SELECT query.

A peculiar condition: 200000 is the minimal number of records to trigger this problem. With less records, the SELECT query returns correct results.

 CREATE TABLE test (c UUID); 
 COPY 200000 RECORDS INTO test FROM '/tmp/data-uuid.csv' DELIMITERS ',';
 SELECT MIN(c) AS mn, MAX(c) AS mx FROM test;
 SELECT MIN(c) AS mn, MAX(c) AS mx FROM test;

Attached file: data-uuid.zip (application/zip, 107840 bytes)
Description: CSV data to populate the table

Comment 21903

Date: 2016-03-14 18:38:19 +0100
From: MonetDB Mercurial Repository <>

Changeset fc1164c392ca made by Jennie Zhang y.zhang@cwi.nl in the MonetDB repo, refers to this bug.

For complete details, see http//devmonetdborg/hg/MonetDB?cmd=changeset;node=fc1164c392ca

Changeset description:

Added test for Bug #3953

Comment 21907

Date: 2016-03-15 10:08:26 +0100
From: MonetDB Mercurial Repository <>

Changeset a6fd9385f8dc made by Sjoerd Mullender sjoerd@acm.org in the MonetDB repo, refers to this bug.

For complete details, see http//devmonetdborg/hg/MonetDB?cmd=changeset;node=a6fd9385f8dc

Changeset description:

All external types are passed as a pointer in a VAR structure.
This fixes bug #3953.

Comment 21908

Date: 2016-03-15 10:10:01 +0100
From: @sjoerdmullender

When it happens only when a table is a certain minimum size, it's a pretty clear indication the problem lies in the mitosis part of the system.

Comment 21966

Date: 2016-03-25 09:59:27 +0100
From: @sjoerdmullender

Jul2015-SP3 has been released.