Category: DB2 Settings

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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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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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Locking 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 available in DB2 that relate to locking. LOCKTIMEOUT This database configuration parameter specifies the time in seconds that a connection will wait for a needed lock before returning an...

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Managing 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 change anything is Circular logging. Circular logging is more often appropriate for databases where you don’t care about the data (seen it for databases supporting Tivoli and...

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HADR

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 extremely up to date. It even has a Synchronous mode that would guarantee that committed transactions on one server would also be...

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Registry 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 imagine they may come up with more that won’t be added to the workload registry variable in real time). I had a whole...