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...)
I upgraded my database a couple of weeks ago and now my users complain their application is slower. They do not provide specifics but they “feel” it is running slower. Sounds familiar?
Every once in a while I get a request that goes like this: “how can I find if some SQL on my database is performing worse over time?”
It is very hard to deal with the ambiguities of some problems like “finding (more...)
Some of you have asked if the “Introducing the eDB360 Tool” session at the Oaktable World 2014 was recorder. Actually it was, and thanks to Kyle Hailey it is now available as well as the slides. Just go to the agenda of this event and click on corresponding link. There you will also find video and/or slides for all other sessions.
Thanks Kyle for making this possible!
The East Cost Oracle Users Group Conference 2014 is next week. To me, ECO is quite special. I am speaking there for my 3rd time!
The ECO group is kind of new (about 4 years old), and it is the clustering of several regional user groups including the Virginia Oracle Users Group, the Eastern States Oracle Applications Users Group, the Hampton Roads Oracle Users Group, and the Southeastern Oracle Users Group.
What I like about (more...)
Every once in a while it comes to my attention that edb360 takes several hours to run. What can be done? My advice is to let it run for several hours if possible. In most environment it completes in less that 1 hour, but I have seen cases where it may take 5 or 6. The reason is simple: too many SQL statements to execute. And some of those queries are executed on top of (more...)
Introducing the eDB360 Tool (Sep 30, 2014)
SQLT XPLORE: The SQLT XPLAIN hidden child (Jun 21, 2014)
SQL Tuning Tools of the Trade (Jun 21, 2014)
SQL Tuning made easier with SQLTXPLAIN (SQLT) (Jun 21, 2014)
Using SQL Plan Management (SPM) to balance Plan Flexibility and Plan Stability (Jun 21, 2014)
Understanding How is that Adaptive Cursor Sharing (ACS) produces multiple Optimal Plans (Jun 21, 2014)