Yes, one separate connection per request, the strange thing is that the problem disappears when I run it in parallel from 2 mclient instances. After doing that, my python code also works without problems.

On 13 Jul 2020, at 10:08 AM, Sjoerd Mullender wrote:

Are you using two separate connection instances in the Python code? The Python code cannot deal with multiple threads using the same connection.

On 10/07/2020 15.09, Ioannis Foufoulas wrote:

...

Hi,

I have a weird error when I am sending the following queries in parallel from 2 different python clients with MAPI:

insert into table1 select numpy_count(c1) as c1 from view; insert into table2 select numpy_count(c1) as c1 from view2;

where numpy_count is:

CREATE or replace AGGREGATE numpy_count(val INTEGER) RETURNS INTEGER LANGUAGE PYTHON { import time time.sleep(3) return val.size };

The error is: pymonetdb.exceptions.OperationalError: GDK reported error: GDKreleasesem: semctl failed: Invalid argument

However, if I run these 2 queries in parallel from 2 instances of mclient they work and AFTER doing this, they also work from python’s client with mapi. Is there any hint on this?

Best, Yannis

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