Hi, I am getting below message when trying to return a list from an ops

is not picklable. You are currently using the fs_io_manager and the multi_or_in_process_executor. You will need to use a different io manager to continue using this output. For example, you can use the mem_io_manager with the in_process_executor

Hmm, I get why this can be confusing. If you were to print out the type of the value that you're returning from the op, what would it be? What's often the case is that the return value for your op isn't actually a list, but rather an instance of a Python class or a generator. Hence why it's not picklable.

You might be right

Object [<sqlalchemy.ext.automap.kpi_selection_group object at 0x7f5e8d3df760>, <sqlalchemy.ext.automap.kpi_selection_group object at 0x7f5e8d3df820>, <sqlalchemy.ext.automap.kpi_selection_group object at 0x7f5e8d3df520>, <sqlalchemy.ext.automap.kpi_selection_group object at 0x7f5e8d3df190>, <sqlalchemy.ext.automap.kpi_selection_group object at 0x7f5e8d3defe0>, <sqlalchemy.ext.automap.kpi_selection_group object at 0x7f5e8d3dee30>, <sqlalchemy.ext.automap.kpi_selection_group object at 0x7f5e8d3deb90>, <sqlalchemy.ext.automap.kpi_selection_group object at 0x7f5e8d3de9e0>, <sqlalchemy.ext.automap.kpi_selection_group object at 0x7f5e8d3de7d0>, <sqlalchemy.ext.automap.kpi_selection_group object at 0x7f5e8d3de5c0>, <sqlalchemy.ext.automap.kpi_selection_group object at 0x7f5e8d418190>, <sqlalchemy.ext.automap.kpi_selection_group object at 0x7f5e8d418340>, <sqlalchemy.ext.automap.kpi_selection_group object at 0x7f5e8d4184f0>, <sqlalchemy.ext.automap.kpi_selection_group object at 0x7f5e8d4186a0>, <sqlalchemy.ext.automap.kpi_selection_group object at 0x7f5e8d418850>, <sqlalchemy.ext.automap.kpi_selection_group object at 0x7f5e8d418a00>, <sqlalchemy.ext.automap.kpi_selection_group object at 0x7f5e8d418bb0>, <sqlalchemy.ext.automap.kpi_selection_group object at 0x7f5e8d418d60>, <sqlalchemy.ext.automap.kpi_selection_group object at 0x7f5e8d418f10>, <sqlalchemy.ext.automap.kpi_selection_group object at 0x7f5e8d4190c0>, <sqlalchemy.ext.automap.kpi_selection_group object at 0x7f5e8d419270>, <sqlalchemy.ext.automap.kpi_selection_group object at 0x7f5e8d419420>, <sqlalchemy.ext.automap.kpi_selection_group object at 0x7f5e8d4195d0>, <sqlalchemy.ext.automap.kpi_selection_group object at 0x7f5e8d419780>, <sqlalchemy.ext.automap.kpi_selection_group object at 0x7f5e8d419930>, <sqlalchemy.ext.automap.kpi_selection_group object at 0x7f5e8d419ae0>, <sqlalchemy.ext.automap.kpi_selection_group object at 0x7f5e8d419c90>, <sqlalchemy.ext.automap.kpi_selection_group object at 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0x7f5e8d430040>, <sqlalchemy.ext.automap.kpi_selection_group object at 0x7f5e8d4300d0>, <sqlalchemy.ext.automap.kpi_selection_group object at 0x7f5e8d430160>]

oh, in you're case we're both right! You're right in that it is a list, but it's a list of sqlalchemy objects, which can't be pickled. you'd likely want to fetch/yield the underlying data from those connections first and then return the list of that data. cheers!

Thanks for the hint, I will go that route.