Radoslav Rusinov

In a recent technical paper Luca Canali explains how to find the mapping between physical storage, ASM allocation units, and database files by querying the undocumented X$ tables.By using the information retrieved from X$KFFXP table he succeeded to:Retrieve a file directly from ASM disksMonitor how the extents in a datafile are allocated across ASM disksMonitor how a datafile is spread across ASMRadoslav Rusinovhttp://www.blogger.com/profile/18163031714036680150noreply@blogger.com0

If you’ve missed to notice – Christo Kutrovsky started his own professional blog dedicated mainly to the Oracle database.Christo Kutrovsky is an Bulgarian Oracle professional currently working in <?xml:namespace prefix = st1 />Canada as a Senior Database/System Administrator for The Pythian Group.His blog is a part of the corporate blog of The Pythian Group.The blog is only two-months old but Radoslav Rusinovhttp://www.blogger.com/profile/18163031714036680150noreply@blogger.com0

IntroductionThe Flashback Database is one of the most powerful new features in Oracle 10g coming as a part of Backup & Recovery enhancements.In this post you can find the result of my research and shared experience about this feature.What is the Oracle Flashback Database?Flashback Database is a part of the backup & recovery enhancements in Oracle 10g Database that are called Flashback Radoslav Rusinovhttp://www.blogger.com/profile/18163031714036680150noreply@blogger.com0

Two weeks ago I had a presentation in front of Bulgarian Oracle User Group about Backup & Recovery Enhancements in Oracle 10g.The agenda of the presentation:Flash Recovery AreaFlashback Technology EnhancementsSpace Pressure & Database HangsPhysical Backup & Recovery EnhancementsIt includes information about enhancements in Oracle 10g (Release 1 and Release 2) related to Human Errors (Flashback Radoslav Rusinovhttp://www.blogger.com/profile/18163031714036680150noreply@blogger.com0

Finally, after 6 months of silence I am writing my first post.In the past several months I didn’t have any free time to update my blog but now I am trying to change this. I hope that I will be able to write here much more frequently.I have a lot of interesting topics to write about. Some of them:- Presentation about Backup & Recovery Enhancements in Oracle 10g that I gave in front of the Radoslav Rusinovhttp://www.blogger.com/profile/18163031714036680150noreply@blogger.com0

A simple chapter from the Jonathan Lewis's book is available for download at this address: Chapter 05: The Clustering FactorThe book will be available for shipping in 5th of November at Amazon online bookstore: Cost-Based Oracle FundamentalsRadoslav Rusinovhttp://www.blogger.com/profile/18163031714036680150noreply@blogger.com2

If you want to benchmark your new Oracle9i/10g database environment before to put it in production as a part of your migration procedure, then may be you are one of these who are facing with the problem: How to test my database, where to find a proper tool or program and how much I must pay for that?I just want to share a links to several free programs that can help you to test your Oracle Radoslav Rusinovhttp://www.blogger.com/profile/18163031714036680150noreply@blogger.com1

This presentation is given on the Oracle OpenWorld this year. You can download it from here: Oracle Database 10g: Best Practices for Windows DeploymentsAnother interesting presentation from OOW 2005 is this one: What They Didn't Print in the Doc - HA Best Practices by the Gurus from Oracle Maximum Availability Architecture TeamRadoslav Rusinovhttp://www.blogger.com/profile/18163031714036680150noreply@blogger.com0

Oracle have released the official version of 10g R2 for Windows.The software can be downloaded from here: Oracle Database 10g DownloadsThe Windows-related documentation for R2 is already available as well: Oracle Database 10g Relase 2 Documentation LibraryRadoslav Rusinovhttp://www.blogger.com/profile/18163031714036680150noreply@blogger.com

Andrew Carr let me to know that there is an interesting follow up to the ASM vs. LVM article on the Wim Coekaerts Blog: ASM vs LVM Wim Coekaerts is the Director of Linux Engineering at Oracle. The post is discussing the interaction between OS buffercache and Oracle buffercache and how they are affected by using ASM or Linux filesystem.Radoslav Rusinovhttp://www.blogger.com/profile/18163031714036680150noreply@blogger.com2

A small introduction: Bitmap indexes are tailored to data warehouses.In its simplest form, a bitmap index on an index consists of one vector of bits (i.e., bitmap) per attribute value, where the size of each bitmap is equal to the number of records in the indexed relation. For example, if the attribute is day of the week, then there would be seven bitmap vectors for that attribute, one for each Radoslav Rusinovhttp://www.blogger.com/profile/18163031714036680150noreply@blogger.com5

Bert Scalzo has published an interesting article in Linux Journal that compares the performance of non-RAC Linux systems, which are using the new Oracle 10g feature - ASM versus using of Linux filesystems: Optimizing Oracle 10g on Linux: Non-RAC ASM vs. LVMRadoslav Rusinovhttp://www.blogger.com/profile/18163031714036680150noreply@blogger.com2

On the web site of The New York Oracle Users Group (NYOUG) you can find some very interesting presentations from the recent NYOUG events:June 2005Things You “Know” - from Tom Kyte, Oracle CorporationResource Mapping: A Wait Time-Based Methodology for Database Performance Analysis – from Matt Larson, Confio SoftwarePresents the Resource Mapping Methodology and how it can be used for Wait-Event Radoslav Rusinovhttp://www.blogger.com/profile/18163031714036680150noreply@blogger.com3

Mike Ault has published an answer to all comments about the recent published article from Don Burleson: Once More Into The FrayAdded from Rado: All of the comments (from Tom Kyte and other visitors) after the above blog post was deleted from Mike as he declares into his post and here: Comment on "Getting Credible Information" blog postAdded from Rado: Sorry but now I just have discovered that Radoslav Rusinovhttp://www.blogger.com/profile/18163031714036680150noreply@blogger.com3

I have updated my post about the _PGA_MAX_SIZE hidden parameter with additional information that pop-up in the past few days.I will appreciate any comments and corrections about my points if you think that they are wrong or you just have more valuable information that I can add to this post.Radoslav Rusinovhttp://www.blogger.com/profile/18163031714036680150noreply@blogger.com0

A new white paper is coming from one of the leading security companies - NGS (Next Generation Security) Software Ltd.It will be related to discovered problems after using of the OPatch utility for applying of Oracle patches and the title is "Patch Verification of Oracle Database Servers".Some quotes from this Eweek news story: Security Firm: Oracle Opatch Leaves Firms Uncovered:A total of more Radoslav Rusinovhttp://www.blogger.com/profile/18163031714036680150noreply@blogger.com0

Pete Finnigan has mentioned my blog in his Oracle Security weblog, especially the security-related post: How to see the MOD_PLSQL passwords in clear textThanks to him for his comments!I want to note that this information can be found at his book: Oracle Security Step-by-Step (Version 2.0) as step 8.1.2 from Phase 8 - Application Servers and the Middle Tier.Additional information online:Fact Radoslav Rusinovhttp://www.blogger.com/profile/18163031714036680150noreply@blogger.com0

Added from Rado (23 August): Don updated his article again yesterday (see the link below). Now it is more detailed and there are lot of quoted documents.But there is again some questionable information:No RAM sort may use more than 5% of pga_aggegate_target or _pga_max_size, whichever is smaller. This means that no task may use more than 200 megabytes for sorting or hash joins.Again, for serial Radoslav Rusinovhttp://www.blogger.com/profile/18163031714036680150noreply@blogger.com13

Check the following links for more details regarding to my previous post (Management of the Oracle9i PGA): Discussion from Don Burleson's Oracle forum: Question for Don, Regarding _pga_max_size Article from Ora!Ora!Oracle mail magazine: Sort Metalink discussion thread: high pga_aggregate_target but low "cache hit percentage" Metalink discussion thread: PGA memory usage exceeding Radoslav Rusinovhttp://www.blogger.com/profile/18163031714036680150noreply@blogger.com5

If you think that your PGA can be configured properly just by increasing of the PGA_AGGREGATE_TARGET parameter, think twice - it is NOT!See this article from Don Burleson: Undocumented secrets for super-sizing your PGAIt shows that there are two hidden parameters that can help for proper using of the PGA. Otherwise, Oracle will never use more than 200 MB for the whole PGA nor will it use more Radoslav Rusinovhttp://www.blogger.com/profile/18163031714036680150noreply@blogger.com3