Error with concurrent inserts via PymonetDB mapi

10 Jul 2020

      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

Error with concurrent inserts via PymonetDB mapi

Ioannis Foufoulas