Known Issues

This page documents known issues that have come up during the development of the wwdtm library. Although many of the issues have been resolved or mitigated by version 2.0.0 of the library, there are some that might pop up in some circumstances.

MySQL Connection Pooling

As of the time of writing this documentation, the use of MySQL Connection Pooling is not officially supported and has not been fully vetted. As such, it is recommended to not use the following configuration keys in the database section of the config.json file.

  • use_pool

    • This key may not be supported by all version of MySQL or MySQL-compatible database servers

  • pool_name

  • pool_size

MySQL sql_mode Flags

Earlier pre-release versions of wwdtm 2.0 had some incompatibilities if the database it is pulling from runs MySQL 5.7 or newer due to a violation of sql_mode flag ONLY_FULL_GROUP_BY. The scripts have caused the violations have been updated and the issue should be resolved starting with the pre-release version 2.0.0-rc.3.

To remove the ONLY_FULL_GROUP_BY flag from the global sql_mode variable, you will first need to query the current value of sql_mode by running:

select @@sql_mode;

Copy the result and remove the ONLY_FULL_GROUP_BY flag from the list and run the following command to unset the flag globally:

set global sql_mode='<flags>';

That will set the sql_mode to the correct value until the service is restarted. To make it persist, you will need to update the mysqld.cnf file on the server with the following configuration line:

sql-mode = <flags>

This will set the sql_mode variable to the list of flags each time the service starts.

A way to validate that the variable change is working as expected, if you have a working copy of the Git repository, is to run pytest to check for errors and messages pertaining to the ONLY_FULL_GROUP_BY flag.