Category: Performance

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Top 10 tips for SQL performance on DB2

Ok, so everyone has their top 10, and some of them are significantly different – but here’s my top 10 on SQL performance for DB2. I mostly share this information with developers, but it’s important for a DBA to be aware of these things. Since it’s directed more at developers, it ignores some of the basics like “do runstats” and...

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What are Parameter Markers?

Parameter Markers Parameter Markers show up as ? in queries when you look at them in a dynamic SQL snapshot or in the sysibmadm views. They show up when the value for a variable is not hard-coded at the time of preparation, but instead is changeable at execution time. I’ve included a couple of code snippets to illustrate what I’m talking about....

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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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DBClean Performance

This is a really complicated topic, largely because dbclean is such a varied tool, and because the data distribution in Commerce databases varries heavily based on how you use it. If you haven’t already, check out my blog entry on dbclean basics. Also, if you’re having performance issues on a specific cleaning area, search my blog for a post on...

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The Least you can do for DB2 Performance

I suspect there are some sites out there where a “set-it-and-forget-it” approach is taken for DB2 related performance. Many clients we go into don’t even realize the need for having a DBA. Depending on site size, that may work for a while. I take an active and proactive role in performance for any client I can. There are some nifty...