https://community.esri.com/t5/arcgis-pro-questions/attributeerror-error-87934-replication-and/m-p/1136076#M50369 <P>Answering questing 3 <A href="https://community.esri.com/t5/python-questions/threading-vs-multiprocessing-for-concurrent-gp/m-p/582360#M45653" target="_self">here.</A></P><BLOCKQUOTE><P>ArcObjects instances (and therefore most arcpy/arcgisscripting objects) cannot cross thread boundaries. That is, if you create an object in one thread, you cannot access it in another.</P></BLOCKQUOTE> Fri, 21 Jan 2022 22:48:32 GMT Anonymous User 2022-01-21T22:48:32Z https://community.esri.com/t5/arcgis-pro-questions/attributeerror-error-87934-replication-and/m-p/1134705#M50151 <P>I needed to run the Subdivide Polygon tool thousands of times, and copy the results to a new geodatabase.</P><P>In arcpy, the Subdivide Polygon tool can be run in parallel using&nbsp;concurrent.futures.&nbsp; As far as I can tell, the output feature classes can only be written to the output geodatabase one at a time (serial) due to locking.</P><P>In the end I had to write a some blocking logic at the <EM>process </EM>level. Each process ran the Subdivide Polygon tool and then waited its turn to copy the output to the geodatabase.</P><P>The problem arose when using multithreading in the main process as well as sub processes from concurrent.futures. Any time I tried to hop threads and share Subdivide Polygon output, arcpy would crash with AttributeError: ERROR 87934.</P><P>&nbsp;</P><P>What does this error actually mean?</P><P>Is it possible to write to a geodatabase in parallel?</P><P>Does arcpy allow multithreading? I'd like to know if this is an implementation problem on my end or if arcpy doesn't play well here.</P><P>&nbsp;</P><P>Reference posts for AttributeError 87934: <A href="https://community.esri.com/t5/python-questions/cherrypy-with-arcpy/td-p/42" target="_self">Cherrypy error</A>, <A href="https://community.esri.com/t5/geoprocessing-questions/geoprocessing-with-cherrypy-web-framework/td-p/65484" target="_self">Using Cherrypy</A>&nbsp;</P> Tue, 18 Jan 2022 18:23:46 GMT https://community.esri.com/t5/arcgis-pro-questions/attributeerror-error-87934-replication-and/m-p/1134705#M50151 Anonymous User 2022-01-18T18:23:46Z https://community.esri.com/t5/arcgis-pro-questions/attributeerror-error-87934-replication-and/m-p/1136076#M50369 <P>Answering questing 3 <A href="https://community.esri.com/t5/python-questions/threading-vs-multiprocessing-for-concurrent-gp/m-p/582360#M45653" target="_self">here.</A></P><BLOCKQUOTE><P>ArcObjects instances (and therefore most arcpy/arcgisscripting objects) cannot cross thread boundaries. That is, if you create an object in one thread, you cannot access it in another.</P></BLOCKQUOTE> Fri, 21 Jan 2022 22:48:32 GMT https://community.esri.com/t5/arcgis-pro-questions/attributeerror-error-87934-replication-and/m-p/1136076#M50369 Anonymous User 2022-01-21T22:48:32Z