Mainframe Scenario & Real Time Interview Q&A Explainer.

1) How to handle Control Interval splits in VSAM? 2)In Db2 how does indexing impact performance? When to prefer a composite index vs single column index 3)How to prevent transaction deadlock and ensure region stability 4)How to design a fail safe approach for abended batch jobs processing million of records 5)Logic to read Vsam file and remove duplicate records ensuring file integrity 6)What kind of mechanism to troubleshoot performance bottlenecks in complex db2 sql queries handling large volumes 7)How to tune Cics region for maximum throughput under High transaction load?