With permission of the Northern California Oracle Users Group (NoCOUG) I am reproducing a warm interview on SQLTXPLAIN and SQLd360. During this interview Mauro Pagano and myself talk about the history behind these two free tools and how the former has evolved into the latter. You can find the full transcript of the interview here: YesSQL(T). If you want to read the entire free online NoCOUG Journal, you will discover other cool articles.
Sometimes you do what you have to do. So here I confess doing something I usually avoid: forcing an Execution Plan (which is not the same as using a more conventional method for Plan stability).
This is a case on 188.8.131.52.0 base release where the application vendor sets the optimizer to 9i, and tweaks other CBO parameters in questionable ways, then some queries produce suboptimal plans (as expected); and you are (more...)
In most cases edb360 takes less than 1hr to execute. But I often hear of cases where it takes a lot longer than that. In a corner case it was taking several days and it had to be killed.
So the question is WHY edb360 takes that long?
Well, edb360 executes thousands of SQL statements sequentially (intentionally). Many of these queries read data from AWR and in particular from ASH. So, lets say your ASH (more...)
Every release of edb360 includes some “new goodies”. Latest version v1510 reduces the number of execution parameters from 2 to just 1. It also incorporates a new configuration file which is mostly static, but it can be user-modified for special cases. And new sections below are all now part of edb360. Enjoy!
Quite often I learn of a system where “nobody changed anything” and suddenly the system is experiencing some strange behavior. Then after diligent investigation it turns out someone changed a little parameter at the System level, but somehow disregarded mentioning it since he/she thought it had no connection to the unexpected behavior. As we all know, System parameters are big knobs that we don’t change lightly, still we often see “unknown” changes like the one described.
During my 17 years at Oracle, I developed several tools and scripts. The largest and more widely used is SQLTXPLAIN. It is available through My Oracle Support (MOS) under document_id 215187.1.
SQLTXPLAIN, also know as SQLT, is a tool for SQL diagnostics, including Performance and Wrong Results. I am the original developer and author, but since very early stages of its development, this tool encapsulates the expertise of many bright engineers, DBAs, developers and (more...)
New tool sqld360 is now available! Mauro Pagano released this cool new tool a few hours ago. And yes, it is free for all!
So, what is sqld360? Well, it is an install-nothing free software that tells you a lot about one SQL statement. And if your site has an Oracle Tuning Pack or Diagnostics Pack license, then you get a lot more from sqld360. Sample snapshot below shows you the dynamic menu for a (more...)
As I get frequent questions about eDB360 I decided to post some FAQ here. First, some links to prior posts:
- Video: Introducing the eDB360 Tool
- What to do if edb360 takes long to run
- What is new with EDB360?
- How to execute eAdam and eDB360
- Meet “edb360″: a free tool that provides a 360-degree view of an Oracle database
Q: When is the best time to execute edb360?
A: At the end of a (more...)
As I help a peer with a SQL Tuning engagement, I face the frequent case of: “We do not want to gather CBO schema object statistics because we don’t want our Execution Plans to change”. Well, the bad news is that: not gathering stats only gives you a false sense of safety because your Execution Plans can change anyways. The reason has to do with Predicates referencing values out of range. Typical cases include range (more...)