For my purposes I'm perfectly happy to use pymysql instead of mysqldb, but
I'll gladly help with further debugging if you wish to chase this down.
Here's the output for the python session:
Python 3.9.7 (default, Sep 16 2021, 13:09:58)
[GCC 7.5.0] :: Anaconda, Inc. on linux
Type "help", "copyright", "credits" or "license" for more information.
>>> from MySQLdb import _mysql
>>> import os
>>> os.system(f"ldd {_mysql.__file__}")
linux-vdso.so.1 (0x00007ffec8a71000)
libmysqlclient.so.18 =>
/home/talens/anaconda3/envs/hatpi/lib/libmysqlclient.so.18
(0x00007f60768ed000)
libpthread.so.0 => /lib/x86_64-linux-gnu/libpthread.so.0
(0x00007f60768b6000)
libc.so.6 => /lib/x86_64-linux-gnu/libc.so.6 (0x00007f60766c4000)
libssl.so.1.1 => /home/talens/anaconda3/envs/hatpi/lib/./libssl.so.1.1
(0x00007f6076633000)
libcrypto.so.1.1 =>
/home/talens/anaconda3/envs/hatpi/lib/./libcrypto.so.1.1
(0x00007f6076366000)
libdl.so.2 => /lib/x86_64-linux-gnu/libdl.so.2 (0x00007f6076360000)
libstdc++.so.6 => /home/talens/anaconda3/envs/hatpi/lib/./libstdc++.so.6
(0x00007f60761e9000)
libgcc_s.so.1 => /home/talens/anaconda3/envs/hatpi/lib/./libgcc_s.so.1
(0x00007f60761d5000)
/lib64/ld-linux-x86-64.so.2 (0x00007f6076cc3000)
libm.so.6 => /lib/x86_64-linux-gnu/libm.so.6 (0x00007f6076086000)
0
On Tuesday, 23 August 2022 at 13:59:31 UTC-4 Mike Bayer wrote:
> okey doke let's see what mysql client library you are running, here's a
> Python session that locates the .so file in use and then runs the ldd
> command, which can give us a clue what you are running, if pymysql has no
> issue then we need to suspect client library as a possible factor.
>
> $ python
> Python 3.10.0 (default, Nov 5 2021, 17:23:47) [GCC 11.2.1 20210728 (Red
> Hat 11.2.1-1)] on linux
> Type "help", "copyright", "credits" or "license" for more information.
> >>> from MySQLdb import _mysql
> >>> import os
> >>> os.system(f"ldd {_mysql.__file__}")
> linux-vdso.so.1 (0x00007ffea07ee000)
> libmariadb.so.3 => /lib64/libmariadb.so.3 (0x00007f37c45fa000)
> libpthread.so.0 => /lib64/libpthread.so.0 (0x00007f37c45f5000)
> libc.so.6 => /lib64/libc.so.6 (0x00007f37c43ed000)
> libz.so.1 => /lib64/libz.so.1 (0x00007f37c43d3000)
> libssl.so.1.1 => /lib64/libssl.so.1.1 (0x00007f37c4336000)
> libcrypto.so.1.1 => /lib64/libcrypto.so.1.1 (0x00007f37c4048000)
> /lib64/ld-linux-x86-64.so.2 (0x00007f37c467f000)
> 0
>
>
>
>
> On Tue, Aug 23, 2022, at 1:12 PM, Geert Jan Talens wrote:
>
> It does happen on every run. I'm not entirely sure how to run it on a
> different server, I'm fairly new to databases. I'm running "mysql Ver
> 8.0.30 for Linux on x86_64 (MySQL Community Server - GPL)".
> The issue does not occur when using pymysql.
> On Tuesday, 23 August 2022 at 12:05:24 UTC-4 Mike Bayer wrote:
>
>
> also try the pymysql DBAPI if that changes things, if this is mariadb try
> mariadb-connector also.
>
> On Tue, Aug 23, 2022, at 12:04 PM, Mike Bayer wrote:
>
> it happens every time the program is run? there's nothing really going
> on in the program here, if I take out the initializer, then the program
> produces lots of stack traces as expected, but even then not the "server
> has gone away" error.
>
> can you try running on a different MySQL /MariaDB server ? like run a
> clean database in a container. What server version ?
>
> On Tue, Aug 23, 2022, at 11:22 AM, Geert Jan Talens wrote:
>
> Hello Mike,
>
> Thank you for your reply. The traceback of the issue is below. I'm using
> sqlalchemy 1.4.40 and MySQLdb 2.1.1, the problem does not occur when using
> sqlite for the database instead.
>
> Regards,
> Geert Jan
>
> Traceback (most recent call last):
> File
> "/home/talens/anaconda3/envs/hatpi/lib/python3.9/site-packages/sqlalchemy/engine/base.py",
>
> line 1900, in _execute_context
> self.dialect.do_execute(
> File
> "/home/talens/anaconda3/envs/hatpi/lib/python3.9/site-packages/sqlalchemy/engine/default.py",
>
> line 732, in do_execute
> cursor.execute(statement, parameters)
> File
> "/home/talens/anaconda3/envs/hatpi/lib/python3.9/site-packages/MySQLdb/cursors.py",
>
> line 206, in execute
> res = self._query(query)
> File
> "/home/talens/anaconda3/envs/hatpi/lib/python3.9/site-packages/MySQLdb/cursors.py",
>
> line 319, in _query
> db.query(q)
> File
> "/home/talens/anaconda3/envs/hatpi/lib/python3.9/site-packages/MySQLdb/connections.py",
>
> line 259, in query
> _mysql.connection.query(self, query)
> MySQLdb._exceptions.OperationalError: (2006, 'MySQL server has gone away')
>
> The above exception was the direct cause of the following exception:
>
> Traceback (most recent call last):
> File
> "/home/talens/Research/HATPI/Projects/testing/testing/database_mp.py", line
> 84, in <module>
> main()
> File
> "/home/talens/Research/HATPI/Projects/testing/testing/database_mp.py", line
> 78, in main
> database_action(20) # Fails if line 1 is insert_integer.
> File
> "/home/talens/Research/HATPI/Projects/testing/testing/database_mp.py", line
> 44, in database_action
> result = query_integer(integer)
> File
> "/home/talens/Research/HATPI/Projects/testing/testing/database_mp.py", line
> 37, in query_integer
> result = session.execute(statement).scalar_one_or_none()
> File
> "/home/talens/anaconda3/envs/hatpi/lib/python3.9/site-packages/sqlalchemy/orm/session.py",
>
> line 1712, in execute
> result = conn._execute_20(statement, params or {}, execution_options)
> File
> "/home/talens/anaconda3/envs/hatpi/lib/python3.9/site-packages/sqlalchemy/engine/base.py",
>
> line 1705, in _execute_20
> return meth(self, args_10style, kwargs_10style, execution_options)
> File
> "/home/talens/anaconda3/envs/hatpi/lib/python3.9/site-packages/sqlalchemy/sql/elements.py",
>
> line 333, in _execute_on_connection
> return connection._execute_clauseelement(
> File
> "/home/talens/anaconda3/envs/hatpi/lib/python3.9/site-packages/sqlalchemy/engine/base.py",
>
> line 1572, in _execute_clauseelement
> ret = self._execute_context(
> File
> "/home/talens/anaconda3/envs/hatpi/lib/python3.9/site-packages/sqlalchemy/engine/base.py",
>
> line 1943, in _execute_context
> self._handle_dbapi_exception(
> File
> "/home/talens/anaconda3/envs/hatpi/lib/python3.9/site-packages/sqlalchemy/engine/base.py",
>
> line 2124, in _handle_dbapi_exception
> util.raise_(
> File
> "/home/talens/anaconda3/envs/hatpi/lib/python3.9/site-packages/sqlalchemy/util/compat.py",
>
> line 208, in raise_
> raise exception
> File
> "/home/talens/anaconda3/envs/hatpi/lib/python3.9/site-packages/sqlalchemy/engine/base.py",
>
> line 1900, in _execute_context
> self.dialect.do_execute(
> File
> "/home/talens/anaconda3/envs/hatpi/lib/python3.9/site-packages/sqlalchemy/engine/default.py",
>
> line 732, in do_execute
> cursor.execute(statement, parameters)
> File
> "/home/talens/anaconda3/envs/hatpi/lib/python3.9/site-packages/MySQLdb/cursors.py",
>
> line 206, in execute
> res = self._query(query)
> File
> "/home/talens/anaconda3/envs/hatpi/lib/python3.9/site-packages/MySQLdb/cursors.py",
>
> line 319, in _query
> db.query(q)
> File
> "/home/talens/anaconda3/envs/hatpi/lib/python3.9/site-packages/MySQLdb/connections.py",
>
> line 259, in query
> _mysql.connection.query(self, query)
> sqlalchemy.exc.OperationalError: (MySQLdb._exceptions.OperationalError)
> (2006, 'MySQL server has gone away')
> [SQL: SELECT mytable.id
> FROM mytable
> WHERE mytable.id = %s]
> [parameters: (20,)]
> (Background on this error at: https://sqlalche.me/e/14/e3q8)
>
> On Monday, 22 August 2022 at 19:19:15 UTC-4 Mike Bayer wrote:
>
>
> your program runs completely (thanks), and I can't reproduce any
> problem. changed line 1 as written to:
>
> # Line 1.
> # If nothing happens on line 1, line 3 fails.
> insert_integer(0) # If I do this (insert-only) line 3 fails.
> #database_action(0) # If I do this (query, insert) line 3 works.
>
>
> and no issue. output is below. Send along a stack trace for more hints.
>
> 2022-08-22 19:16:02,322 INFO sqlalchemy.engine.Engine SELECT DATABASE()
> 2022-08-22 19:16:02,322 INFO sqlalchemy.engine.Engine [raw sql] ()
> 2022-08-22 19:16:02,322 INFO sqlalchemy.engine.Engine SELECT @@sql_mode
> 2022-08-22 19:16:02,322 INFO sqlalchemy.engine.Engine [raw sql] ()
> 2022-08-22 19:16:02,323 INFO sqlalchemy.engine.Engine SELECT
> @@lower_case_table_names
> 2022-08-22 19:16:02,323 INFO sqlalchemy.engine.Engine [raw sql] ()
> 2022-08-22 19:16:02,323 INFO sqlalchemy.engine.Engine BEGIN (implicit)
> 2022-08-22 19:16:02,324 INFO sqlalchemy.engine.Engine SELECT COUNT(*) FROM
> information_schema.tables WHERE table_schema = %s AND table_name = %s
> 2022-08-22 19:16:02,324 INFO sqlalchemy.engine.Engine [generated in
> 0.00016s] ('test', 'mytable')
> 2022-08-22 19:16:02,325 INFO sqlalchemy.engine.Engine
> DROP TABLE mytable
> 2022-08-22 19:16:02,325 INFO sqlalchemy.engine.Engine [no key 0.00012s] ()
> 2022-08-22 19:16:02,330 INFO sqlalchemy.engine.Engine COMMIT
> 2022-08-22 19:16:02,330 INFO sqlalchemy.engine.Engine BEGIN (implicit)
> 2022-08-22 19:16:02,331 INFO sqlalchemy.engine.Engine SELECT COUNT(*) FROM
> information_schema.tables WHERE table_schema = %s AND table_name = %s
> 2022-08-22 19:16:02,331 INFO sqlalchemy.engine.Engine [cached since
> 0.006941s ago] ('test', 'mytable')
> 2022-08-22 19:16:02,332 INFO sqlalchemy.engine.Engine
> CREATE TABLE mytable (
> id INTEGER NOT NULL,
> PRIMARY KEY (id)
> )
>
>
> 2022-08-22 19:16:02,333 INFO sqlalchemy.engine.Engine [no key 0.00140s] ()
> 2022-08-22 19:16:02,342 INFO sqlalchemy.engine.Engine COMMIT
> 2022-08-22 19:16:02,344 INFO sqlalchemy.engine.Engine BEGIN (implicit)
> 2022-08-22 19:16:02,345 INFO sqlalchemy.engine.Engine INSERT INTO mytable
> (id) VALUES (%s)
> 2022-08-22 19:16:02,345 INFO sqlalchemy.engine.Engine [generated in
> 0.00021s] (0,)
> 2022-08-22 19:16:02,346 INFO sqlalchemy.engine.Engine COMMIT
> 2022-08-22 19:16:02,362 INFO sqlalchemy.engine.Engine BEGIN (implicit)
> 2022-08-22 19:16:02,362 INFO sqlalchemy.engine.Engine BEGIN (implicit)
> 2022-08-22 19:16:02,365 INFO sqlalchemy.engine.Engine SELECT mytable.id
> FROM mytable
> WHERE mytable.id = %s
> 2022-08-22 19:16:02,365 INFO sqlalchemy.engine.Engine SELECT mytable.id
> FROM mytable
> WHERE mytable.id = %s
> 2022-08-22 19:16:02,365 INFO sqlalchemy.engine.Engine [generated in
> 0.00024s] (1,)
> 2022-08-22 19:16:02,365 INFO sqlalchemy.engine.Engine [generated in
> 0.00024s] (3,)
> 2022-08-22 19:16:02,366 INFO sqlalchemy.engine.Engine ROLLBACK
> 2022-08-22 19:16:02,366 INFO sqlalchemy.engine.Engine ROLLBACK
> 2022-08-22 19:16:02,367 INFO sqlalchemy.engine.Engine BEGIN (implicit)
> 2022-08-22 19:16:02,367 INFO sqlalchemy.engine.Engine BEGIN (implicit)
> 2022-08-22 19:16:02,367 INFO sqlalchemy.engine.Engine INSERT INTO mytable
> (id) VALUES (%s)
> 2022-08-22 19:16:02,367 INFO sqlalchemy.engine.Engine [cached since
> 0.0218s ago] (3,)
> 2022-08-22 19:16:02,367 INFO sqlalchemy.engine.Engine INSERT INTO mytable
> (id) VALUES (%s)
> 2022-08-22 19:16:02,367 INFO sqlalchemy.engine.Engine [cached since
> 0.02189s ago] (1,)
> 2022-08-22 19:16:02,367 INFO sqlalchemy.engine.Engine COMMIT
> 2022-08-22 19:16:02,367 INFO sqlalchemy.engine.Engine COMMIT
> 2022-08-22 19:16:02,368 INFO sqlalchemy.engine.Engine BEGIN (implicit)
> 2022-08-22 19:16:02,369 INFO sqlalchemy.engine.Engine SELECT mytable.id
> FROM mytable
> WHERE mytable.id = %s
> 2022-08-22 19:16:02,369 INFO sqlalchemy.engine.Engine [cached since
> 0.003665s ago] (4,)
> 2022-08-22 19:16:02,369 INFO sqlalchemy.engine.Engine BEGIN (implicit)
> 2022-08-22 19:16:02,369 INFO sqlalchemy.engine.Engine SELECT mytable.id
> FROM mytable
> WHERE mytable.id = %s
> 2022-08-22 19:16:02,370 INFO sqlalchemy.engine.Engine [cached since
> 0.004593s ago] (2,)
> 2022-08-22 19:16:02,370 INFO sqlalchemy.engine.Engine ROLLBACK
> 2022-08-22 19:16:02,370 INFO sqlalchemy.engine.Engine ROLLBACK
> 2022-08-22 19:16:02,370 INFO sqlalchemy.engine.Engine BEGIN (implicit)
> 2022-08-22 19:16:02,370 INFO sqlalchemy.engine.Engine BEGIN (implicit)
> 2022-08-22 19:16:02,370 INFO sqlalchemy.engine.Engine INSERT INTO mytable
> (id) VALUES (%s)
> 2022-08-22 19:16:02,370 INFO sqlalchemy.engine.Engine [cached since
> 0.0254s ago] (4,)
> 2022-08-22 19:16:02,371 INFO sqlalchemy.engine.Engine INSERT INTO mytable
> (id) VALUES (%s)
> 2022-08-22 19:16:02,371 INFO sqlalchemy.engine.Engine [cached since
> 0.02555s ago] (2,)
> 2022-08-22 19:16:02,371 INFO sqlalchemy.engine.Engine COMMIT
> 2022-08-22 19:16:02,371 INFO sqlalchemy.engine.Engine COMMIT
> 2022-08-22 19:16:02,372 INFO sqlalchemy.engine.Engine BEGIN (implicit)
> 2022-08-22 19:16:02,372 INFO sqlalchemy.engine.Engine SELECT mytable.id
> FROM mytable
> WHERE mytable.id = %s
> 2022-08-22 19:16:02,372 INFO sqlalchemy.engine.Engine [cached since
> 0.007373s ago] (5,)
> 2022-08-22 19:16:02,373 INFO sqlalchemy.engine.Engine ROLLBACK
> 2022-08-22 19:16:02,373 INFO sqlalchemy.engine.Engine BEGIN (implicit)
> 2022-08-22 19:16:02,373 INFO sqlalchemy.engine.Engine BEGIN (implicit)
> 2022-08-22 19:16:02,373 INFO sqlalchemy.engine.Engine SELECT mytable.id
> FROM mytable
> WHERE mytable.id = %s
> 2022-08-22 19:16:02,373 INFO sqlalchemy.engine.Engine [cached since
> 0.008211s ago] (7,)
> 2022-08-22 19:16:02,373 INFO sqlalchemy.engine.Engine INSERT INTO mytable
> (id) VALUES (%s)
> 2022-08-22 19:16:02,373 INFO sqlalchemy.engine.Engine [cached since
> 0.02819s ago] (5,)
> 2022-08-22 19:16:02,374 INFO sqlalchemy.engine.Engine ROLLBACK
> 2022-08-22 19:16:02,374 INFO sqlalchemy.engine.Engine COMMIT
> 2022-08-22 19:16:02,374 INFO sqlalchemy.engine.Engine BEGIN (implicit)
> 2022-08-22 19:16:02,374 INFO sqlalchemy.engine.Engine INSERT INTO mytable
> (id) VALUES (%s)
> 2022-08-22 19:16:02,374 INFO sqlalchemy.engine.Engine [cached since
> 0.0291s ago] (7,)
> 2022-08-22 19:16:02,375 INFO sqlalchemy.engine.Engine COMMIT
> 2022-08-22 19:16:02,375 INFO sqlalchemy.engine.Engine BEGIN (implicit)
> 2022-08-22 19:16:02,375 INFO sqlalchemy.engine.Engine SELECT mytable.id
> FROM mytable
> WHERE mytable.id = %s
> 2022-08-22 19:16:02,375 INFO sqlalchemy.engine.Engine [cached since
> 0.01013s ago] (6,)
> 2022-08-22 19:16:02,375 INFO sqlalchemy.engine.Engine ROLLBACK
> 2022-08-22 19:16:02,376 INFO sqlalchemy.engine.Engine BEGIN (implicit)
> 2022-08-22 19:16:02,376 INFO sqlalchemy.engine.Engine BEGIN (implicit)
> 2022-08-22 19:16:02,376 INFO sqlalchemy.engine.Engine INSERT INTO mytable
> (id) VALUES (%s)
> 2022-08-22 19:16:02,376 INFO sqlalchemy.engine.Engine [cached since
> 0.03086s ago] (6,)
> 2022-08-22 19:16:02,376 INFO sqlalchemy.engine.Engine SELECT mytable.id
> FROM mytable
> WHERE mytable.id = %s
> 2022-08-22 19:16:02,376 INFO sqlalchemy.engine.Engine [cached since
> 0.01102s ago] (8,)
> 2022-08-22 19:16:02,376 INFO sqlalchemy.engine.Engine COMMIT
> 2022-08-22 19:16:02,377 INFO sqlalchemy.engine.Engine ROLLBACK
> 2022-08-22 19:16:02,377 INFO sqlalchemy.engine.Engine BEGIN (implicit)
> 2022-08-22 19:16:02,377 INFO sqlalchemy.engine.Engine INSERT INTO mytable
> (id) VALUES (%s)
> 2022-08-22 19:16:02,377 INFO sqlalchemy.engine.Engine [cached since
> 0.03192s ago] (8,)
> 2022-08-22 19:16:02,377 INFO sqlalchemy.engine.Engine COMMIT
> 2022-08-22 19:16:02,378 INFO sqlalchemy.engine.Engine BEGIN (implicit)
> 2022-08-22 19:16:02,378 INFO sqlalchemy.engine.Engine SELECT mytable.id
> FROM mytable
> WHERE mytable.id = %s
> 2022-08-22 19:16:02,378 INFO sqlalchemy.engine.Engine [cached since
> 0.01299s ago] (9,)
> 2022-08-22 19:16:02,378 INFO sqlalchemy.engine.Engine ROLLBACK
> 2022-08-22 19:16:02,379 INFO sqlalchemy.engine.Engine BEGIN (implicit)
> 2022-08-22 19:16:02,379 INFO sqlalchemy.engine.Engine INSERT INTO mytable
> (id) VALUES (%s)
> 2022-08-22 19:16:02,379 INFO sqlalchemy.engine.Engine [cached since
> 0.03381s ago] (9,)
> 2022-08-22 19:16:02,379 INFO sqlalchemy.engine.Engine COMMIT
> 2022-08-22 19:16:02,381 INFO sqlalchemy.engine.Engine BEGIN (implicit)
> 2022-08-22 19:16:02,381 INFO sqlalchemy.engine.Engine SELECT mytable.id
> FROM mytable
> WHERE mytable.id = %s
> 2022-08-22 19:16:02,381 INFO sqlalchemy.engine.Engine [cached since
> 0.01605s ago] (10,)
> 2022-08-22 19:16:02,381 INFO sqlalchemy.engine.Engine ROLLBACK
> 2022-08-22 19:16:02,382 INFO sqlalchemy.engine.Engine BEGIN (implicit)
> 2022-08-22 19:16:02,382 INFO sqlalchemy.engine.Engine INSERT INTO mytable
> (id) VALUES (%s)
> 2022-08-22 19:16:02,382 INFO sqlalchemy.engine.Engine [cached since
> 0.03694s ago] (10,)
> 2022-08-22 19:16:02,383 INFO sqlalchemy.engine.Engine COMMIT
> 2022-08-22 19:16:02,387 INFO sqlalchemy.engine.Engine BEGIN (implicit)
> 2022-08-22 19:16:02,388 INFO sqlalchemy.engine.Engine SELECT mytable.id
> FROM mytable
> WHERE mytable.id = %s
> 2022-08-22 19:16:02,388 INFO sqlalchemy.engine.Engine [generated in
> 0.00011s] (20,)
> 2022-08-22 19:16:02,389 INFO sqlalchemy.engine.Engine ROLLBACK
> 2022-08-22 19:16:02,389 INFO sqlalchemy.engine.Engine BEGIN (implicit)
> 2022-08-22 19:16:02,389 INFO sqlalchemy.engine.Engine INSERT INTO mytable
> (id) VALUES (%s)
> 2022-08-22 19:16:02,389 INFO sqlalchemy.engine.Engine [cached since
> 0.04428s ago] (20,)
> 2022-08-22 19:16:02,390 INFO sqlalchemy.engine.Engine COMMIT
>
>
> On Mon, Aug 22, 2022, at 4:21 PM, Geert Jan Talens wrote:
>
> Hi,
>
> I am trying to perform some database actions after multiprocessing some
> database manipulations but in most cases I get:
> sqlalchemy.exc.OperationalError: (MySQLdb._exceptions.OperationalError)
> (2006, 'MySQL server has gone away')
>
> The code below is a working example of the problem I'm having, where the
> success of line 3 (in main) for some reason depends on what happens on line
> 1.
>
> Any help would be appreciated!
>
> Regards,
> Geert Jan
>
> from sqlalchemy import create_engine, select
> from sqlalchemy import Column, Integer
> from sqlalchemy.orm import declarative_base, sessionmaker
>
> import multiprocessing as mp
> import numpy as np
>
> Base = declarative_base()
> Session = sessionmaker()
>
>
> class MyTable(Base):
> """This table lists all observed frames."""
>
> __tablename__ = 'mytable'
>
> # Columns in the table.
> id = Column(Integer, primary_key=True, autoincrement=False)
>
>
> def insert_integer(integer):
>
> with Session() as session:
>
> record = MyTable(id=int(integer))
> session.add(record)
> session.commit()
>
> return
>
>
> def query_integer(integer):
>
> with Session() as session:
>
> statement = select(MyTable).where(MyTable.id == int(integer))
> result = session.execute(statement).scalar_one_or_none()
>
> return result
>
>
> def database_action(integer):
>
> result = query_integer(integer)
> if result is None:
> insert_integer(integer)
> else:
> print("integer already in database.")
>
> return
>
>
> def initializer(engine):
> # Doesn't matter if I use on or the other.
> engine.dispose(close=False)
> # engine.pool = engine.pool.recreate()
>
>
> def main():
>
> # Database setup.
> engine = create_engine("mysql+mysqldb://user:[email protected]/testdb
> <http://user:[email protected]/testdb>")
> Session.configure(bind=engine)
> Base.metadata.drop_all(bind=engine)
> Base.metadata.create_all(bind=engine)
>
> # Line 1.
> # If nothing happens on line 1, line 3 fails.
> # insert_integer(0) # If I do this (insert-only) line 3 fails.
> database_action(0) # If I do this (query, insert) line 3 works.
>
> # Line 2.
> with mp.Pool(2, initializer, (engine,)) as pool:
> pool.map(database_action, np.arange(1, 11))
>
> # Line 3.
> database_action(20) # Fails if line 1 is insert_integer.
>
> return
>
>
> if __name__ == '__main__':
> main()
>
>
> --
> SQLAlchemy -
> The Python SQL Toolkit and Object Relational Mapper
>
> http://www.sqlalchemy.org/
>
> To post example code, please provide an MCVE: Minimal, Complete, and
> Verifiable Example. See http://stackoverflow.com/help/mcve for a full
> description.
> ---
> You received this message because you are subscribed to the Google Groups
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> To view this discussion on the web visit
> https://groups.google.com/d/msgid/sqlalchemy/5597b069-3725-44de-88c4-4964d95d84cen%40googlegroups.com
>
> <https://groups.google.com/d/msgid/sqlalchemy/5597b069-3725-44de-88c4-4964d95d84cen%40googlegroups.com?utm_medium=email&utm_source=footer>
> .
>
>
>
> --
> SQLAlchemy -
> The Python SQL Toolkit and Object Relational Mapper
>
> http://www.sqlalchemy.org/
>
> To post example code, please provide an MCVE: Minimal, Complete, and
> Verifiable Example. See http://stackoverflow.com/help/mcve for a full
> description.
> ---
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> .
>
>
>
>
> --
> SQLAlchemy -
> The Python SQL Toolkit and Object Relational Mapper
>
> http://www.sqlalchemy.org/
>
> To post example code, please provide an MCVE: Minimal, Complete, and
> Verifiable Example. See http://stackoverflow.com/help/mcve for a full
> description.
> ---
> You received this message because you are subscribed to the Google Groups
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> .
>
>
>
--
SQLAlchemy -
The Python SQL Toolkit and Object Relational Mapper
http://www.sqlalchemy.org/
To post example code, please provide an MCVE: Minimal, Complete, and Verifiable
Example. See http://stackoverflow.com/help/mcve for a full description.
---
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