Category: Troubleshooting

0

What 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 the parameters mentioned here without understanding the impact on your application. Currently Committed This is new behavior in DB2 9.7. It has a similar effect to...

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Introducing 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 come straight out of the info center, but I’ll add my own experiences and insight geared towards e-commerce databases and throw in specifics for WebSphere Commerce from...

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WebSphere Commerce Instance Creation Doesn’t Like DB2 9.7 FixPack 5

This post is specific to WebSphere Commerce. We spent a fair amount of time on this, both on a SUSE server and a Red Hat Server. The problem manifested in different ways. The main thing that became obvious to me is that Commerce was not creating the Commerce database as the dbaUser specified in createInstance.properties file, but was instead using the...

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Analyzing 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. Edit on 09/29/2016: Correction to the SQL for counting statements when context data is collected. Also formatted the SQL statements to be easier to read. So you can still use...

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Analyzing 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, but not yet removed. This means that even in 9.7, you can still create them and work with them. If you’re at all confused about the difference between deadlocks and...

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SQL Analysis Overview

So I thought I’d do a short series on analyzing SQL. I want to focus on some of the techniques I use, so not necessarily everything you could know about it, but some basics on one way to do it. I’m going to focus on what you can do manually with no pay-for-use or even tools that require additional installation tasks. There are multiple...

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Identifying Problem SQL

Many DBAs have their own methods and approaches in this area,  but there are some basic sources and methods that I use. I’ll cover at least the basics of SQL  analysis in one or more future posts Get SQL from Developers So the optimum situation is that your developers give you the SQL they’re planning to use in custom code...

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Locks – Timeout vs. Deadlock

So questions in this area most often come from DBAs from other RDBMS’s or from developers. I’ll probably write other posts on locks, but here are the basics on deadlocks vs. timeouts. Why we get them confused at all Ah the wisdom that went into grouping these under a single error code with different return/reason codes. For whatever reason, both...

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db2diag Tool for Parsing the Diagnostic Log

Understanding the db2 diagnostic log takes a while when you’re new to DB2. Then you get better at spotting what is actually a problem. But there’s still so much there sometimes. How many messages for stmm adjustments or archived log files do I have to scroll through to find what I’m really looking for? This week I had an instance...