Calling the REST API intermittently results in 500 errors

Issue Summary

This issue has been created in response to https://community.developer.atlassian.com/t/getting-jdbc-and-sql-exception-for-some-api-calls/43530.

Once in a while our atlassian-connect-express app receives a 500 code for API calls with information like:

 

{{

{\"statusCode\":500,\"message\":\"org.springframework.orm.hibernate5.HibernateJdbcException: JDBC exception on Hibernate data access: SQLException for SQL [n/a]; SQL state [57014]; error code [0]; could not extract ResultSet; nested exception is org.hibernate.exception.GenericJDBCException: could not extract ResultSet\"}

"}}

It is not clear why these exceptions sometimes happen. It seems they occur more often on some days than others, and if they happen in one instance, they are likely to happen in another instance also.

Steps to Reproduce

1. Develop an app that calls the Confluence Cloud REST API.
2. Expand parameters ~ ?expand=space,history,version,ancestors,metadata.properties,children.attachment
   other Params might also cause this issue

Expected Results

500 errors are never returned.

Actual Results

500 errors randomly occur (details above).

Workaround

None. The APIs being called may not be idempotent so it is not safe to retry the call.