MonetDB set specific embedded python version - monetdb

Question

In a Linux environment, I'd like to be able to set the embedded python3 to a specific python version. My current monetDB install seems to use 3.7 even though all default python paths point to 3.8.6.
Is there a way to set my 3.8.6 install as the default embedded python3 version?

Answer 1

After some experimentation, the problem seems to be the following: because you are installing MonetDB using apt, the installation pulls the python version that the distribution has packaged in apt. I assume that you are building your container starting from python:3.8. This is based on Debian Buster that packages Python 3.7.
In a bit more detail:
I built a container using the following Dockerfile:
FROM python:3.8
RUN apt-get update
RUN apt-get upgrade -y
COPY ./monetdb.list /etc/apt/sources.list.d/
COPY ./MonetDB-GPG-KEY /
RUN apt-key add /MonetDB-GPG-KEY
RUN apt-get update
RUN apt-get install -y monetdb5-sql monetdb-client monetdb-python3
with the files monetdb.list and MonetDB-GPG-KEY as described in the downloads page.
I then created a database farm and a new database in the container, setting embedpy3 to true:
root#bd0420e945e8:/# monetdbd create /tmp/dbfarm
root#bd0420e945e8:/# monetdbd start /tmp/dbfarm
root#bd0420e945e8:/# monetdb create -p monetdb pytestdb
created database with password for monetdb user: pytestdb
root#bd0420e945e8:/# monetdb set embedpy3=yes pytestdb
Using mclient I created a Python UDF that returns as a string the version of the embedded python interpreter:
CREATE FUNCTION pyversion ()
RETURNS STRING
LANGUAGE python {
import sys
return sys.version
};
When I called it I got the following result:
sql>select pyversion();
+-----------------------------------------------------+
| %2 |
+=====================================================+
| 3.7.3 (default, Jul 25 2020, 13:03:44) |
: [GCC 8.3.0] :
+-----------------------------------------------------+
1 tuple
I repeated the above process starting from a different distribution (Ubuntu Focal) that packages a different version of Python (It seems that Ubuntu has updated to Python 3.8.5 since the release of Focal).
FROM ubuntu:20.04
RUN apt-get update
RUN apt-get upgrade -y
RUN apt-get install -y gnupg ca-certificates
COPY ./monetdb.list /etc/apt/sources.list.d/
COPY ./MonetDB-GPG-KEY /
RUN apt-key add /MonetDB-GPG-KEY
RUN apt-get update
RUN apt-get install -y monetdb5-sql monetdb-client monetdb-python3
In this container the function pyversion returns the following:
sql>select pyversion();
+-----------------------------------------------------+
| %2 |
+=====================================================+
| 3.8.5 (default, Jul 28 2020, 12:59:40) |
: [GCC 9.3.0] :
+-----------------------------------------------------+
1 tuple
In conclusion, I would suggest to either build MonetDB from source in the container (see the README for instructions), or build your container starting from a distribution that packages Python 3.8 in its package manager.