I am trying to read records from SAP ASE 16 Database table concurrently using java to increase performance. I am using select…..for update query to read database table records concurrently. Here two threads are trying to read records from single table.
I am executing this command on a microservice based environment.
I have done below configuration on database:
• I have enabled select for update using: sp_configure "select for update", 1
• To set locking scheme I have used: alter table poll lock datarows
Table name: poll
This is the query that I am trying to execute:
SQL Query:
SELECT e_id, e_name, e_status FROM poll WHERE (e_status = 'new') FOR UPDATE
UPDATE poll SET e_status = 'polled' WHERE (e_id = #e_id)
Problem:
For some reason I am getting duplicate records on executing above query for majority of records sometimes beyond 200 or 300.
It seems like locks are not being acquired during execution of above command. Is there any configuration that I am missing from database side. Does it have anything to do with shared lock and exclusive lock?
