Calculating disk space usage on an exadata.
I have been working on figuring out where all our space is, and how much space is actually available on our Exadata. First to clarify what all the calculations are based on.1/2 Rack. Sata drives....
View ArticleDisk space layout on your Exadata
This blog post is a product of my last post on Exadata disk usage.I have multiple exadatas (both full Rack and 1/2 Racks), and I want to know exactly how each one is configured, now that ACS has left....
View ArticleOLTP compression slow for large data set
I am working on loading a large dataset (about 500 Million rows that take up about 100g of space).I am loading them into a partitioned table and I was hoping to use HCC compression, but at least OLTP...
View ArticleSetting aside a node for maintenance on Exadata
Actually, this isn't exadata specific, but it becomes even more important on a multi-node cluster.First the background. I have a data warehouse application in which we are loading up lots of data. At...
View ArticleIOUG Real World Performance tour
Last Thursday the Real World Performance Tour came to Rochester, NY.I know what you're probably thinking. One of 2 things.1) Why did it come there, aren't you a suburb of NYC (we are actually about a 7...
View ArticleBenchmarks for CPU's
I have been doing some benchmarks on a couple of different systems for LIO's. I have been using Kevin Closson's great SLOB toolkit. You can find more information about it on his blog here.I have been...
View ArticleCooking for Geeks (shameless plug)
I am part of the O-Really Blogger review program, and long, long ago I picked up the book"Cooking for Geeks" by Jeff Potter for review. This was a fantastic book.. I am both a geek, and cook. This...
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R and visualing your execution times
Well, I think I'm a little late to the party.. I know Greg Rahn did a great post on utilizing R to visual your ash data. I figure I would do a simple example of how to build something myself to show...
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Analyzing the last query run
I don't know how many times I find myself trying to tune a query, and going through the same tasks.I run the sql in my session (most likely on sqlplus on the unix server), but I then try to track down...
View ArticleHyperthreading with Oracle (update)
After my first post on hyperthreading, and all the hits I've been getting I've decided to update it..My first post was pased on testing with a DL980.. This is an 8 socket server with X7560 @ 2.27GHz...
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Analytical functions
I have been working on a query that is uses an analytical function..I’m not familiar with them, but using my usual query tuning got me into some trouble..This is the query.WITHSACOMMON71991 AS (select...
View ArticleWhere is my space on DBFS
I just ran into an issue on DBFS where I ran out of space.First here is the df -kFilesystem 1K-blocks Used Available Use% Mounted ondbfs-dbfs_admin2@:/ 20983808 11443696 9540112 55% /dbfs/dbaOK,...
View ArticleProblem debugging for DBFS
In trying to find out the cause of a DBFS issue, I learned what is expected (or helpful) when working with Support on DBFS issues.1) Logon trigger for dbfs user to create a trace file..CREATE OR...
View ArticleTaking a career change
Well, I have decided to make a change and take a job with oracle. I am very excited about this move, and I look forward to being more involved in big data. As any of you know (who have read my blog...
View ArticleAWR compare report
I came across this while doing some dbreplays, and found it very useful.First, lets say you have a RAC cluster, and you want to do some performance comparisons .. What's one of the issues you run into...
View ArticleWhat happened to my sql (sql_id) ?
While finishing up a few things, I ran across a query that wasn't playing nicely. It had 4 different plans over the course of the last couple of days, and I wanted to see what happend.. I came up with...
View ArticleExadata tips
I wanted to write up an Exadata tip that I learned. Background : I wanted to do a simple "select count(1) from mytable". mytable has a primary key on it. The count seemed to be taking a long time...
View ArticleWhat extended stats do I have on my database?
I've been starting to work with Extended statistics to help the optimizer find the best plan. This is a great feature that is outlined by @sqlmaria (Maria Coogan) here.But once you create extended...
View ArticleExadata sizing updated for 3tb drives 1/2 rack SATA
OK, Now I new Exadata coming in that has 3tb drives, and the first question asked is .. How much disk to I have to configure on it ? Well I'm going to expand on a previous entry I did on sizing .1/2...
View ArticleRecognize the magic optimizer numbers
Well I figured I document some of the magic numbers that the optimizer uses to help remember them, and help others. The back ground of this is simple. I was looking through a query that was running for...
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