server crashes when executing particular loopback query in embedded python

[monetdb-team]

Date: 2016-06-06 10:57:19 +0200
From: fioravanzos
To: Embedded devs <>
Version: unspecified
CC: @njnes

Last updated: 2017-10-26 14:01:28 +0200

Comment 22196

Date: 2016-06-06 10:57:19 +0200
From: fioravanzos

User-Agent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10_11_5) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/50.0.2661.102 Safari/537.36
Build Identifier:

If I execute a loopback query with a min() or max() statement in it, monet crashes.
mserver5 outputs 'segmentation fault'.
Example of function used:
CREATE FUNCTION myfunc() RETURNS TABLE(n STRING) LANGUAGE PYTHON {
res = _conn.execute("SELECT max(d) FROM mytable;")
result = dict()
result['n'] = str(res)
return result
};

Using the function without min() or max() in the query does not arise any issue.

Reproducible: Always

Steps to Reproduce:

1.Create function
2.Executed function
3.Server crashed

Actual Results:

Server crashes, segmentation fault

Expected Results:

Returned a table with the min or max result

Comment 24971

Date: 2017-02-03 17:15:12 +0100
From: @sjoerdmullender

Is this still a problem? I tried:

sql>create table mytable (d int);
operation successful (13.110ms)
sql>create function myfunc() returns table(n string) language python {
more> res = _conn.execute("SELECT max(d) FROM mytable;")
more> result = dict()
more> result['n'] = str(res)
more> return result
more>};
operation successful (1.2s)
sql>insert into mytable values (10);
1 affected row (5.312ms)
sql>insert into mytable values (20);
1 affected row (5.973ms)
sql>select * from myfunc();
+----------------------------------+
| n |
+==================================+
| {'L3': array([20], dtype=int32)} |
+----------------------------------+
1 tuple (9.596ms)

I.e., no crash. This was in the Dec2016 branch.

Comment 24982

Date: 2017-02-07 09:14:39 +0100
From: fioravanzos

Indeed the issue seems to have been resolved.
Thank you!