BUG #18534: ERROR: portal "C_n" does not exist type of error getting thrown.

The following bug has been logged on the website:

Bug reference:      18534
Logged by:          madhuri nehe
Email address:      nehemadhuri@gmail.com
PostgreSQL version: 15.3
Operating system:   Linux
Description:

1. This issue occurs in multithreaded application.
2. We retrieve records from a single table and store them in the ResultSet
object of JDBC.
3. To read the records sequentially from the ResultSet object, we employ the
rSet.next() method for iteration.
4. We are encountering a sporadic portal exception triggered by the
rSet.next() method call.
5. We have examined all potential causes, such as verifying the executed
query, checking if the ResultSet cursor is open or closed, ensuring the
database connection object is active, and confirming the prepared statement
cursor’s status. No issues have been detected. Also, ResultSet is not being
accessed by multiple threads simultaneously.
 
We've been thorough in our search for the cause of the issue but haven't
found anything yet.