Before you read on, please check out my related post on "Function Result Cache". You may find it valuable in this context. Conversation sounds familiar? I am sure you have been privy to a conversation like this between an IT manager and a DBA: Manager: My query is extremely slow. Can you make the query … Continue reading Oracle – Fastest Way To Execute SQL Is? To, Not Execute It! – Query Result Cache – Part II
If you are running into memory issues such as below, there could be several causes but one of the causes is excessive parallelism and exhaustion of PGA memory. “ORA-01034: ORACLE not available / ORA-27102: out of memory / Linux-x86_64 Error: 12: Cannot allocate” Please read on to find out how to resolve this. There are … Continue reading Oracle – Parallel To PGA (P2P) & Serial To SGA (S2S) – Caching Differences And When Parallelism Is Not The Panacea For Performance!
Caution: If there is no need to use a dynamic SQL, you should always use regular non-dynamic SQL. This is a bad usage of dynamic SQL and I am only doing so to illustrate the use of bind variables. The task: Again, I just wanted to provide a basic example that shows the usage of EXECUTE … Continue reading Oracle Tip – EXECUTE IMMEDIATE With Bind Variable Input In Dynamic SQL
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 … Continue reading Oracle REDO – A Basic Explanation
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. … Continue reading Oracle – Is my APPEND Hint Being Ignored? How To Find Out?