Oracle – Why Is Toad Asking Me To Commit/Rollback A SELECT With No Transaction?

Commit or rollback a SELECT, really? Occasionally, you would be working with your favorite Oracle tool and when you are ready to close the tool, it will prompt you to either commit or rollback your work. “What work?”, you wonder. The problem is, you have only done SELECT’s. Why is it prompting you to commit …

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Oracle – PL/SQL – Using ROW/TABLE Locks To Implement Application/Job Semaphore To Handle Race Conditions

What is a Semaphore? Instead of a clinical illustration of exclusive row lock and exclusive table lock usage in Oracle, here we will try to use them to highlight a higher level concept – Implement a semaphore mechanism. Wikipedia defines semaphore as below: In computer science, a semaphore is a variable or abstract data type …

Oracle REDO – A Basic Explanation

In an earlier post, we saw how Oracle’s UNDO works in very basic terms. REDO is another critical aspect that goes hand in hand with UNDO. Let us get the basics of REDO sorted out here. UNDO and REDO In its most basic sense UNDO is information saved to get back in case a ROLLBACK …

Oracle – Is my APPEND Hint Being Ignored? How To Find Out?

Why is the APPEND hint so great? In a prior post, we extolled the virtues of the APPEND hint (AKA Direct Path Insert). It is a great option to use • UNDO usage is negligible. It is only generated for index maintenance and meta data changes. The keyword is index maintenance – indexes generate UNDO. …

Oracle Gotcha For The SQL Server Developer – DDL’s COMMIT Transactions Implicitly!

If you are primarily a SQL Server developer and you are moving to Oracle, this is one of the nastiest surprises in store for you. You are so used to rolling back everything including DDL in SQL Server transactions but in Oracle, DDL inside transactions act as COMMIT. Fear not though, there are a ton …