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DB2 LUW – What is a Page?
The logical view of a database consists of the standard objects in any RDBMS – Tables, Indexes, etc. There are a number of layers of abstraction between this and the physical hardware level, both in...
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Two Worlds of DB2 LUW Performance Monitoring
I generally suggest both my readers and my clients turn on the monitor switches using the DFT_MON* parameters in the DBM CFG. However, I find myself using traditional snapshots less and less. The main...
View ArticleHADR_TIMEOUT vs. HADR_PEER_WINDOW
It has taken me a while to fully understand the difference between HADR_TIMEOUT and HADR_PEER_WINDOW. I think there is some confusion here, so I’d like to address what each means and some...
View ArticleSQL5005C and Ulimit Issues
I’m spoiled. While we build a fair number of environments each year, we also have basic starting standards. Because of this, I sometimes miss the basics when a problem shows up. Or at least it takes me...
View ArticleDo you see a ‘Congested’ State for HADR while Performing Reorgs?
I monitor HADR closely, and want to be paged out if HADR goes down. Why? Because any subsequent failure would then be a serious problem. Once HADR has a problem, I suddenly have a single point of...
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Informational Constraints – Benefits and Drawbacks
One of the most frustrating things a DBA can experience is troubleshooting due to bad data. The client is upset because rows are missing or incorrect data is returned. The client facing web front end...
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STMM Analysis Tool
I mostly like and use DB2’s Self Tuning Memory Memory Manager (STMM) for my OLTP databases where I have only one DB2 Instance/Database on a database server. I do have some areas that I do not let it...
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Quick Hit Tips – CPUSPEED, RESTRICTIVE, and DB2_WORKLOAD
Today we are going to talk about some random DB2 features that can’t stand in a blog of their own, but are worth discussing nonetheless. These are tidbits I had discovered during “DB2’s Got Talent”...
View ArticleGiving Automatic Maintenance a Fair Try
I’m a control freak. I think that control freaks tend to make good DBAs as long as they don’t take it too far. My position for years has been that I would rather control my runstats, reorgs, and...
View ArticleAnalyzing Package Cache Size
Note: updated 7/21 to reflect location of the package cache high water mark in the MON_GET* table functions I have long been a fan of a smaller package cache size, particularly for transaction...
View ArticleIssues with STMM
I thought I’d share some issues with STMM that I’ve seen on Linux lately. I’ve mostly been a fan of STMM, and I still am for small environments that are largely transaction processing and have only one...
View ArticleRegistry Variables and DB2_WORKLOAD=WC
I was happy to see the new workload registry variable in Commerce 7/DB2 9. Mostly out of laziness – it requires fewer variables to be set manually, but it also ensures that nothing major is missed (I...
View ArticleHADR
What is HADR? HADR is DB2’s implementation of log shipping. Which means it’s a shared-nothing kind of product. But it is log shipping at the Log Buffer level instead of the Log File level, so it can be...
View ArticleManaging db2 transaction log files
Logging method There are two methods of logging that DB2 supports: Circular and Archive. I believe Oracle has similar modes. Circular To my extreme disgust, the default that Commerce uses if you don’t...
View ArticleLocking Parameters
So I thought I’d write a post covering locking parameters. This is by no means a comprehensive coverage of isolation levels and locking, but more of a practically oriented guide to the parameters...
View ArticleAnalyzing Deadocks – the old way
In 9.7, DB2 started offering a new monitoring method for deadlocking. Though this post describes the “old” way, this method also works in db2 9.7. Detailedeadlock event monitors have been deprecated,...
View ArticleAnalyzing Deadlocks – the new way
The section titled “To Format the Output to a Flat File” was updated on 2/13/2012. Edit on 12/11/2014: This new method of analyzing locking issues became available in DB2 9.7. So you can still use the...
View ArticleHow to use the DB2 Governor to force off long idle connections
Ok, so the DB2 Governor is deprecated with 9.7. But it’s only replacement is a pay-for-use tool – the workload manager. So I imagine I’ll be writing a script to do the very basic things that I do with...
View ArticleIntroducing Parameter Wednesday – DBM CFG: NUMDB
This is a new blog post format I’m introducing. I’m declaring Wednesday Parameter Day. That means each Wednesday, I’ll pick a parameter and cover it in excruciating detail. Some of the details will...
View ArticleWhat DBAs can do to Reduce Deadlocks
Deadlocking is an application problem. There are only a few things that DBAs can do to reduce deadlocking, and they all require buy-in from the application. Let me repeat that another way. Don’t set...
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