Use a ThreadPoolExecutor instead of a ProcessPoolExecutor in dbserver.py because SQLite in macOS is not fork-safe; using the ProcessPoolExecutor a 'ProgrammingError: Cannot operate on a closed database' error is raised. Se also https://bugs.python.org/issue27126
Use a ThreadPoolExecutor instead of a ProcessPoolExecutor in dbserver.py
because SQLite in macOS is not fork-safe; using the ProcessPoolExecutor
a 'ProgrammingError: Cannot operate on a closed database' error is
raised. Se also https://bugs.python.org/issue27126

gem/oq-engine,gem/oq-engine,gem/oq-engine,gem/oq-engine,gem/oq-engine