Structured Data

Oracle OpenWorld 2010: Sessions By OakTable Members

Greg Rahn — Thu, 02 Sep 2010 19:45:12 +0000

As Oracle OpenWorld is just around the corner and you are probably getting your session schedule together, I thought I’d pass on this (nearly complete) list of sessions of which one or more of the presenters is an OakTable member. There is no doubt in my mind that these sessions will contain some of the best technical content presented at OpenWorld so be sure and pre-register for these sessions today. Hope to see you there!

Oracle Exadata and Netezza TwinFin Compared – An Engineer’s Analysis

Greg Rahn — Wed, 11 Aug 2010 04:07:15 +0000

There seems to be little debate that Oracle’s launch of the Oracle Exadata Storage Server and the Sun Oracle Database Machine has created buzz in the database marketplace. Apparently there is so much buzz and excitement around these products that two competing vendors, Teradata and Netezza, have both authored publications that contain a significant amount of discussion about the Oracle Database with Real Application Clusters (RAC) and Oracle Exadata. Both of these vendor papers are well structured but make no mistake, these are marketing publications written with the intent to be critical of Exadata and discuss how their product is potentially better. Hence, both of these papers are obviously biased to support their purpose. My intent with this blog post is simply to discuss some of the claims, analyze them for factual accuracy, and briefly comment on them. After all, Netezza clearly states in their publication: The information shared in this paper is made available in the spirit of openness. Any inaccuracies result from our mistakes, not an intent to mislead. In the interest of full disclosure, my employer is Oracle Corporation, however, this is a personal blog and what I write here are my own ideas and words (see [...]

New Outfit, New Style

Greg Rahn — Sun, 01 Aug 2010 11:00:05 +0000

Back on June 17th WordPress 3.0 “Thelonious” was released and it offered up a handful of new features. Just a few days ago (July 29th) the 3.0.1 release went GA so I decided it was time to investigate what the new 3.0 ready themes had to offer. After looking through a handful of themes I decided to give the Magazine Basic theme a try for now. It offered a 1024 pixel wide layout and threaded comments; two of the features I was really looking for. Feel free to share your comments: good, bad or otherwise. Thanks! Here is a capture of the previous version just in case you don’t recall what it looked like (click for full size).

The Core Performance Fundamentals Of Oracle Data Warehousing – Set Processing vs Row Processing

Greg Rahn — Tue, 20 Jul 2010 09:00:38 +0000

[back to Introduction] In over six years of doing data warehouse POCs and benchmarks for clients there is one area that I frequently see as problematic: “batch jobs”. Most of the time these “batch jobs” take the form of some PL/SQL procedures and packages that generally perform some data load, transformation, processing or something similar. The reason these are so problematic is that developers have hard-coded “slow” into them. I’m generally certain these developers didn’t know they had done this when they coded their PL/SQL, but none the less it happened. So How Did “Slow” Get Hard-Coded Into My PL/SQL? Generally “slow” gets hard-coded into PL/SQL because the PL/SQL developer(s) took the business requirements and did a “literal translation” of each rule/requirement one at a time instead of looking at the “before picture” and the “after picture” and determining the most efficient way to make those data changes. Many times this can surface as cursor based row-by-row processing, but it also can appear as PL/SQL just running a series of often poorly thought out SQL commands. Hard-Coded Slow Case Study The following is based on a true story. Only the facts names have been changed to protect the innocent. Here is [...]

Oracle OpenWorld 2010: The Oracle Real-World Performance Group

Greg Rahn — Tue, 13 Jul 2010 14:01:53 +0000

Now that Oracle OpenWorld 2010 is just under 70 days away I thought I would take a moment to mention that the Oracle Real-World Performance Group will again be hosting three sessions. This year I think we have a very exciting and informative lineup of sessions that are a must-attend for those wanting to see and hear Oracle Database performance insight right from Oracle’s own performance engineers. Hope to see you there! And for those who are interested, there will likely be many discussions about the Oracle Database Machine and Oracle Exadata. Very hot stuff! Session ID: S317164 (Monday 2:00PM) Session Title: The Latest Real World Performance Challenges Session Abstract: Oracle’s Real-World Performance Group — the group that first presented at Oracle OpenWorld parallel query techniques with partitions, the index-less database, cardinality challenges with the optimizer, over-processed databases and connection storms — this year presents the performance issues before you experience them and how to plan for future projects with success. All topics discussed in this session come from the Real-World Performance Group’s observations and problem solving. Session ID: S317166 (Monday 5:00PM) Session Title: Real-World Performance Panel Session Session Abstract: This session is your chance, via written questions, to ask a [...]

Fully Exploiting Exadata

Greg Rahn — Thu, 08 Jul 2010 10:30:28 +0000

As a member of the Real-World Performance Group at Oracle I have participated in quite a number of Exadata POCs over the past two years. Often times those POCs are constrained in a number of ways: time, schema/app modifications, etc., because the objective is a proof, not a full blown migration. As a result there is often significant performance that is left on the table just waiting to be fully exploited — the kind of performance that really makes a database performance engineer excited — mind blowing performance. This includes, but is not limited to, data model changes, SQL query modifications and re-engineering batch processes. The reason these types of modifications get me so excited is that design decisions are often influenced by the then current deployment platform and with the Exadata powered Oracle Database Machine those restrictions are frequently lifted. You see, with Exadata the rules change, and so should your design decisions. Sure, you could just pluck-and-plop an existing Oracle data warehouse database onto an Oracle Database Machine and it would likely run much faster than it does on your current system, and you will be wowed, but you very well may shouting four letter expletives describing how [...]

10.2.0.5 Patch Set For Oracle Database Server

Greg Rahn — Fri, 30 Apr 2010 18:04:25 +0000

Just a quick post that the 10.2.0.5 patch set for Oracle Database Server was released for x86 & x86-64 platforms on April 29th. The patchset number is 8202632 and is available for download from My Oracle Support.

The Core Performance Fundamentals Of Oracle Data Warehousing – Data Loading

Greg Rahn — Fri, 23 Apr 2010 16:00:33 +0000

[back to Introduction] Getting flat file data into your Oracle data warehouse is likely a daily (or more possibly frequent) task, but it certainly does not have to be a difficult one. Bulk loading data rates are governed by the following operations and hardware resources: How fast can the data be read How fast can data be written out How much CPU power is available I’m always a bit amazed (and depressed) when I hear people complain that their data loading rates are slow and they proceed to tell me things like: The source files reside on a shared NFS filer (or similar) and it has just a single GbE (1 Gigabit Ethernet) network path to the Oracle database host(s). The source files reside on this internal disk volume which consists of a two disk mirror (or a volume with very few spindles). Maybe it’s not entirely obvious so let me spell it out (as I did in this tweet): One can not load data into a database faster than it can be delivered from the source. Database systems must obey the laws of physics! Or putting it another way: Don’t fall victim to slow data loading because of a slow performing data source. [...]

The Core Performance Fundamentals Of Oracle Data Warehousing – Parallel Execution

Greg Rahn — Mon, 19 Apr 2010 15:00:25 +0000

[back to Introduction] Leveraging Oracle’s Parallel Execution (PX) in your Oracle data warehouse is probably the most important feature/technology one can use to speed up operations on large data sets. PX is not, however, “go fast” magic pixi dust for any old operation (if thats what you think, you probably don’t understand the parallel computing paradigm). With Oracle PX, a large task is broken up into smaller parts, sub-tasks if you will, and each sub-task is then worked on in parallel. The goal of Oracle PX: divide and conquer. This allows a significant amount of hardware resources to be engaged in solving a single problem and is what allows the Oracle database to scale up and out when working with large data sets. I though I’d touch on some basics and add my observations but this is by far not an exhaustive write up on Oracle’s Parallel Execution. There is an entire chapter in the Oracle Database documentation on PX as well as several white papers. I’ve listed all these in the Resources section at the bottom of this post. Read them, but as always, feel free to post questions/comments here. Discussion adds great value. A Basic Example of Parallel Execution [...]

The Core Performance Fundamentals Of Oracle Data Warehousing – Partitioning

Greg Rahn — Mon, 25 Jan 2010 12:00:01 +0000

[back to Introduction] Partitioning is an essential performance feature for an Oracle data warehouse because partition elimination (or partition pruning) generally results in the elimination of a significant amount of table data to be scanned. This results in a need for less system resources and improved query performance. Someone once told me “the fastest I/O is the one that never happens.” This is precisely the reason that partitioning is a must for Oracle data warehouses – it’s a huge I/O eliminator. I frequently refer to partition elimination as the anti-index. An index is used to find a small amount data that is required; partitioning is used to eliminate vasts amounts of data that is not required. Main Uses For Partitioning I would classify the main reasons to use partitioning in your Oracle data warehouse into these four areas: Data Elimination Partition-Wise Joins Manageability (Partition Exchange Load, Local Indexes, etc.) Information Lifecycle Management (ILM) Partitioning Basics The most common partitioning design pattern found in Oracle data warehouses is to partition the fact tables by range (or interval) on the event date/time column. This allows for partition elimination of all the data not in the desired time window in queries. For example: If I have a [...]