Structured Data: Oracle Database Performance And Scalability Blog

Oracle Myth Busting: Show, Don’t Tell

December 16, 2007
Richard Foote has recently started blogging (as of December 11th) and one of his recent posts discusses Oracle Myths and Information Pollution. I find this topic very interesting as I'm always amazed at the number of people who make changes to their production database based on the results from their favorite Internet search engine, and don't even bother to test it themselves first! Like Richard, I'd encourage anyone who gets information from the Internet to do your diligence and understand the why, and not just the results someone else observed. I guess one could associate it to ...

Posted in Oracle, Troubleshooting | 1 Comment »

Oracle Optimizer Development Team Starts A Blog

December 5, 2007
Since the introduction of the Cost Based Optimizer (CBO) in Oracle 7.0, people have been both fascinated and terrified by it and the statistics that feed it. There has long been a belief that a degree in witchcraft or black magic is required to successfully work with the CBO. Some people feel this shroud of mystery is caused in part by the lack of documentation or detailed examples about the Optimizer. In order to help remove this shroud and the black magic that surround the Optimizer, the development team responsible for it have started a blog. The blog postings ...

Posted in Execution Plans, Optimizer, Oracle, Performance, Statistics, Troubleshooting | 8 Comments »

Oracle Database 11g Release 1 (11.1.0.6.0) for HP-UX PA-RISC

November 21, 2007
Oracle Database 11g Release 1 (11.1.0.6.0) was released for HP-UX PA-RISC today (11/21). Grab it from the Oracle Database Software Downloads on OTN.

Posted in 11gR1, Oracle | No Comments »

Troubleshooting Bad Execution Plans

November 21, 2007
One of the most common performance issues DBAs encounter are bad execution plans. Many try to resolve bad executions plans by setting optimizer related parameters or even hidden underscore parameters. Some even try to decipher a long and complex 10053 trace in hopes to find an answer. While changing parameters or analyzing a 10053 trace might be useful for debugging at some point, I feel there is a much more simple way to start to troubleshoot bad execution plans. Verify The Query Matches The Business Question This seems like an obvious thing to do, but I've seen numerous cases ...

Posted in Execution Plans, Optimizer, Oracle, Performance, SQL Tuning, Statistics, Troubleshooting | 23 Comments »

The Real-World Performance Group: Oracle OpenWorld 2007 Recap

November 19, 2007
Oracle OpenWorld 2007 has come and gone and from the Real-World Performance Group's perspective we'd consider it a successful one. The content of this year's presentations seems to have gone over quite well as shown by the number of hallway comments and emails we received. At least two Oracle bloggers have put up their thoughts on the sessions: Doug Burns: OOW - Day 4 - Performance Day and OOW Day 5 Andrew Clarke: OOW2K7: The Real World Performance Group Many thanks to both Doug and Andrew for the nice write-ups and the kind words, as well as those of you who ...

Posted in Data Warehousing, Execution Plans, Optimizer, Oracle, Performance, SQL Tuning, Statistics, VLDB | 3 Comments »

Oracle Database 11g Release 1 (11.1.0.6.0) for Windows x64, Solaris, AIX, HP-UX

November 12, 2007
Oracle Database 11g Release 1 (11.1.0.6.0) was released for Windows x64 on Friday (11/9) and on Solaris (SPARC 64-bit), AIX and HP-UX Itanium today (11/12). Grab it from the Oracle Database Software Downloads on OTN.

Posted in 11gR1, Oracle | No Comments »

Oracle 11g: Extended Statistics

October 31, 2007
In the Real-World Performance Roundtable, Part 2: The Optimizer, Schema Statistics, SQL Tuning at Oracle OpenWorld 2006, I worked an example of how the optimizer can have difficulty estimating the correct cardinality when there is data correlation. (The Zodiac example can be found on pages 46-49 of the presentation.) In Oracle 11g, there has been some enhancements to help the optimizer deal with data correlation. DBMS_STATS.CREATE_EXTENDED_STATS Previously I blogged about the 11g enhancement to DBMS_STATS.AUTO_SAMPLE_SIZE and the new algorithm for gathering NDV. One of the other enhancements to DBMS_STATS is the CREATE_EXTENDED_STATS function. It is this function that will ...

Posted in 11gR1, Data Warehousing, Execution Plans, Optimizer, Oracle, SQL Tuning, Statistics, VLDB | 9 Comments »

Ideas For Oracle Performance Topics

October 26, 2007
From time to time I get a little writer's block and sometime search for topics to blog about. I thought, what better way to get ideas for blog posts than to ask the readers of this blog. Here is your chance to influence the topic of upcoming blog posts. I just have a few requests to keep things orderly: Topics should in the context of the Oracle database and performance there of. It's not meant to be a Q & A, but rather the subject of a blog post. Try to say as much as necessary, with the least ...

Posted in Oracle, Performance, Troubleshooting | 2 Comments »