Some of my clients, instead of engaging me for day-to-day support, engage me for expert assistance only when it all really hits the fan. This issue occurred for one of those clients, who had other support performing the HADR failovers while the Linux kernel was upgraded.… Read the rest

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SQL1643C on Rollforward

I ran into this error message recently and thought I’d describe what the issue was.

The Scenario

I was building a new consolidated development database server for a client – moving away from 10 separate database servers to one (big) VM to run their development workloads.… Read the rest

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Query Performance Analysis

Some of the more complicated work a DBA does is often analyzing a query. Whether it is proactive or in response to a performance problem, there are so many factors that go into query performance. Even when looking at a query that has a performance problem, there is only occasionally a single, obvious cause for all of the problems.… Read the rest

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Determining Log Span


Some time ago, I wrote a post that suggested using the NUM_LOG_SPAN database configuration parameter to prevent long-running transactions from filling your transaction log.

Using NUM_LOG_SPAN will indeed prevent the problem of long running transcations causing log file saturation, but what if you just want to find applications could become a problem, before the problem happens?… Read the rest

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Comparing dsmtop and db2top

dsmtop is a long-awaited refresh of the wildly popular db2top. Like db2top, dsmtop is a free tool, included with DB2. It is in the base DB2 install starting with 11.1, and can be installed on DB2 10.1 or 10.5.

History of db2top

As I personally recall, db2top first came out of IBM AlphaWorks.… Read the rest

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Finding the Subnet Mask on AIX

This is something DB2 DBAs may need to do as a part of setting up TSAMP. Nearly every server I’ve done before has had a subnet mask of, but I ran into a server recently that wasn’t, and thought I would share how I figured out what it should be (alone, in the middle of the night, during an upgrade).… Read the rest

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