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Race Condition For First Run

See original GitHub issue

When spawning multiple studies with the same postgres backend, the script crashes because each process tries to create the db table.

Expected behavior

db lock, no crash.

Environment

Optuna version: 1.2.0
Python version: 3.8

Error messages, stack traces, or logs

..
sqlalchemy.exc.ProgrammingError: ... relation "alembic_version" already exists
..
sqlalchemy.exc.IntegrityError: ... duplicate key value violates unique constraint "pg_type_typename_nsp_index"
..

Steps to reproduce

[delete optuna db tables]
python exp.py exp1 &
python exp.py exp2 &
python exp.py exp3 &

Additional context (optional)

only tried postgres

Issue Analytics

State:
Created 3 years ago
Comments:5 (2 by maintainers)

Top GitHub Comments

2reactions

elbarocommented, Apr 6, 2020

Thanks, it solved my problem.

0reactions

jkterry1commented, Dec 1, 2021

@c-bata I’m encountering a similar seeming problem, however I don’t quite follow the solution you proposed and as best I can tell the documentation for it hasn’t been updated either. If you could please explain it in a little more detail I’d be happy to create a PR adding this to the documentation