Database crashes after generate_series query

[monetdb-team]

Date: 2017-01-27 13:59:53 +0100
From: @rkoopmanschap
To: SQL devs <>
Version: 11.23.13 (Jun2016-SP2)
CC: @kutsurak, @mlkersten, @njnes

Last updated: 2017-03-03 10:24:41 +0100

Comment 24929

Date: 2017-01-27 13:59:53 +0100
From: @rkoopmanschap

User-Agent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10_12_1) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/55.0.2883.95 Safari/537.36
Build Identifier:

The command below crashes MonetDB. The function returns a table and so this is not the correct way to call it. However, it would be better if it did not cause a crash and instead returned an error.

Reproducible: Always

Steps to Reproduce:

Give the following command in mclient:
SELECT generate_series(1,4);

Actual Results:

Database crashes

Expected Results:

An error message

Comment 24930

Date: 2017-01-27 22:34:43 +0100
From: @mlkersten

The generator function is called in the FROM clause.
select * from generate_series(1,4);

However, this short cut makes sense as well
sql>explain select generate_series(1,4);
+-------------------------------------------------------------------------------------------------+
| mal |
+=================================================================================================+
| function user.s6_1():void; |
| X_3:void := querylog.define("explain select generate_series(1,4);", "default_pipe", 8:int); |
| X_9:bat[:bte] := generator.series(1:bte, 4:bte); |
| sql.resultSet(".L2", "L2", "tinyint", 8:int, 0:int, 7:int, X_9); |
| end user.s6_1;

However, now a crash occurs in mvc_scalar_value_wrap which assumes a scalar and not a BAT. The MAL signature allows for any type.

Comment 24931

Date: 2017-01-27 22:46:41 +0100
From: @sjoerdmullender

Also see bug #3609 which was basically the same problem, except with the three argument version of generate_series. The difference is that the two argument version goes through rel_binop and the three argument version through rel_nop. The latter was fixed, the former wasn't.

Comment 24932

Date: 2017-01-27 22:51:20 +0100
From: @kutsurak

The problem is related to binary operators returning tables. Specifically

sql>SELECT 1 + 3;
+------+
| L2 |
+======+
| 4 |
+------+
1 tuple (0.693ms)

works correctly. On the other hand:

sql>SELECT generate_series(1, 4, 2);
SELECT: no such operator 'generate_series'

Furthermore:

sql>CREATE FUNCTION ser(i integer, j integer) RETURNS TABLE(foo integer) LANGUAGE PYTHON {
more>result = dict()
more>result['foo'] = list(range(i, j))
more>return result
more>};
operation successful (8.281ms)
sql>select ser(1, 4);

server crashes

I think that the correct behavior is the parse error as in the three argument case (maybe with a more informative error message).

Comment 24935

Date: 2017-02-01 13:41:34 +0100
From: MonetDB Mercurial Repository <>

Changeset 4ecdec1a1ebf 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=4ecdec1a1ebf

Changeset description:

fixed bug #6196. Make sure we correctly check the cardinality of table functions.

Comment 24936

Date: 2017-02-01 13:46:09 +0100
From: @njnes

solved by properly checking when table functions are allowed

Comment 25124

Date: 2017-03-03 10:24:41 +0100
From: @sjoerdmullender

Dec2016-SP2 has been released, incorporating the fix.