Database servers these days sometimes have a profusion of IP Addresses. IP V4, V6, management networks, and Virtual IP addresses all add to the ways applications connect in to a database server. I ran into an issue recently where I really needed to know what IP address was being used by an application, and thought I would share what I learned.… Read the restContinue reading »
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 restContinue reading »
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 restContinue reading »
Corrected on 9/8/2017 to reflect correct syntax to eliminate just the one table.
The application in this case – SPSS – maintains an exclusive lock at all times on one table. I think this is poor application design, but IBM was not willing to change it when we brought it to their attention in a PMR.… Read the restContinue reading »
I think that one of my least favorite phrases is “Nothing else changed!” More common than a performance problem that simply slowly creeps up with performance getting worse and worse over time is the sudden performance problem. Many times, sudden database performance problems can be mapped back to a specific change at some level.… Read the restContinue reading »
DBAs excitedly pack their bags for a week-long trip. On-call rotation is hurriedly passed to the next poor soul on the rotation list. Ember dons her trademark pigtails. Melanie Stopfer crams another 20 slides into and already packed presentation.… Read the restContinue reading »
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.
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
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 restContinue reading »
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 255.255.255.0, 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 restContinue reading »