Hi guys,i have a query rule which gets data from database,and i have placed this

I would first validate your database schema and verify the mappings in your database.

Here is a thread where a user experienced a similar issue: forum.appian.com/.../4856

You can verify the following items.
1) Is Appian upgraded recently?
2) Verify the Primary Datasource.
3) In Data Source, you can verify the entity mappings.
4) Does the query rule exist? You can probably run getcontentdetailsbyuuid() custom function to find this. I see the UUID in the post
5) If it exists, does it run when run from a rule.
6) Is script task set to Run as whoever designed the process.
7) Is the Datastore security set with proper access rights?

script task has been set to Run as whoever designed the process and i have access rights

@sivashankari,when iam verifying Data Source iam getting error message like
"An error occurred while attempting to verify the data store: The primary datasource cannot be reached. Details: could not load an entity: [com.appiancorp.type.model.DatatypeModel#3059] (APNX-1-4179-002"

when i used getcontentdetailsbyuuid(),i got details like "testqueryrule: Type: Rule or Constant, Name: getTipRDPEscalationProcessDtls, Id: 79963, Parent: TIP Query Rule".this means query rule exists right?

Restart JBoss and check the the application-server.log, pay special attention to the section of this log that shows the startup of JBoss, JBoss connects to the primary data source during startup, if there's a problem with your configuration files or with the communication with the database, the error should be informative enough.

Just a question, does this problem happen only to this data store or to all data stores?
Another test you can do is to check if Query DB nodes work. Instead of using a predefined datasource in the node, enter the connection details manually and check if you are able to connect to the DB.
Do this exercise, identify whether there are errors or not. Hope this helps.

above exception raised for this Datastore ,and the other problem is the flow is hanging(not moving forward) at onether Datastore

Finally we fixed this issue by restarting Server.
Thank you everyone