When running a flow that contains a REST action that retrieves a large amount of data, the flow will hang with an "Unable to deserialize process plan from JSON" exception. This can also causes a problem when glide.db.trace=true, such as on a production system.
You can reproduce this issue in either of two ways.
Enable the ServiceNow IntegrationHub Installer plugin.
Set a MID Server and point it to the test instance.
Load the attached update set.
The update contains the following test data:
Connection alias: RestPerfTestWithMid
Basic auth credential: InstanceAdminForMID (update the credential to connection to test instance if necessary)
Update the Connection URL to the test instance.
Action "GetCMDBComputerData" has REST step to get cmdb_ci_computer data from the instance. The cmdb_ci_computer contains 800 records.
Flow PertTestRESTBetweenMIDandInstanceWithLargeData use the Action GetCMDBComputerData and glide record lookup action to force the flow switch between instance and MID
Run the flow and notice the flow will hang after run the second GetCMDBComputerData action.
The exception "Unable to deserialize process plan from JSON" appears in the log.
Set glide.db.trace = true.
Create a simple run once flow with a single log action.
Try to test the flow.
See the that the test hangs.
Check the property in Scripts - Background with gs.print(gs.getProperty(‘glide.db.trace’));