If you haven’t been under a rock you know that Larry Ellison announced the Oracle Exadata Storage Server and the HP Oracle Database Machine at Oracle OpenWorld 2008. There seems to be quite a bit of interest and excitement about the product and I for one will say that I am extremely excited about...
Extreme Buzz About Oracle OpenWorld
Last week I read Mark Rittman’s post and today I was reading this InfoWorld article and a few others that are speculating what will be the big news this year at Oracle OpenWorld. I guess the first teaser was given out by Larry Ellison on the F4Q08 earnings call on June 25: We have...
Understanding Performance
There has been some debate in forumsphere/blogosphere centered around Steve Karam’s observation of a 20x elapsed time difference in an update statement “by only changing the block size”. At this point in time, it is pretty much understood (I hope) that this performance delta is directly related to bug 6918210. This bug manifests its...
Automatic DB_FILE_MULTIBLOCK_READ_COUNT
Note: Originally this experiment was from a post I wrote on the Oracle Forum: Database – General. I recommend that you read Jonathan Lewis’ summarization of the thread instead of reading all 671 posts (as of today). You will spend much less time and get more out of the discussion. One of the new...
Oracle 11g: Incremental Global Statistics On Partitioned Tables
Previously I blogged about the new and improved DBMS_STATS.AUTO_SAMPLE_SIZE used to calculate NDV in Oracle 11g and now I wanted to touch on another new feature of DBMS_STATS in 11g: Incremental Global Statistics On Partitioned Tables. Before Incremental Global Stats (Two-Pass Method) When DBMS_STATS.GATHER_TABLE_STATS collects statistics on a partitioned table, generally it does so...
Oracle OpenWorld 2008: The Real-World Performance Group
With Oracle OpenWorld 2008 only a few months away, I thought I would take a moment to mention that the Real-World Performance Group will again be hosting three sessions. If you were at the sessions last year, then you probably know how good they were. If you didn’t make it, you can check out...
Using Bitmap Indexes Effectively
Recently I was reading this thread, “Trying to make use of bitmap indexes” on the Oracle Forum. Before I had finished a working example, Jonathan Lewis had posted his response which was on par with my thoughts. Since this is a topic I see frequently, I thought I would finish my experiment and publish...
Null-Aware Anti-Join
Recently someone showed me a query execution plan with an operation of HASH JOIN ANTI NA. At first, it was thought maybe it was a bug and the operation had a type-o in it, but after further research it was discovered it was a valid operation and a new cost-based query transformation for subquery...
Top Ways How Not To Scale Your Data Warehouse
Working in the Real-World Performance Group at Oracle has allowed me to see quite a few customers’ data warehouses. Unfortunately some customers find their data warehouse suffering from performance problems, not because there is a platform issue, but often because the features are not used or are not used correctly. I thought I’d put...
Choosing An Optimal Stats Gathering Strategy
Recently the Oracle Optimizer Development Team put out a White Paper entitled Upgrading from Oracle Database 9i to 10g: What to expect from the Optimizer. This paper discusses the main differences between 9i and 10g in the subject area of the Optimizer and Statistics. As G.I. Joe said, “Now we know! And knowing is...
Awareness Test
I came across this video the other day and I immediately thought of rule #3 from my Got Root Cause? post: “Be detail oriented, but do not become too obsessed with any one detail.“ Watch the video and see if you pass the Awareness Test. Most importantly, remember the punch line of the video...