Author: Ian Bjorhovde

IanB 6

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? Understanding LSNs Most DBAs...

IanB 2

Monitoring Extent Movement Progress

Since DB2 9.7, you have been able to reduce the size of tablespaces using the statement: ALTER TABLESPACE USERSPACE1 REDUCE MAX Using this functionality, however, requires that the tablespace uses automatic storage and that it was created with the reclaimable storage attribute. Unfortunately, tablespaces created in DB2 9.5 or earlier will not have the reclaimable storage attribute, and it’s not...

log-file-saturation 7

Preventing Log Saturation

A few days ago, I was involved in a conversation on Twitter with Ember and Erwin Hattingh, a DB2 DBA from the Netherlands whom I met at IDUG in Dublin last November. Ember expressed her surprise at how well DB2 handled a nasty situation: It's not every day #DB2 blows your mind with the ability to stay up in a...

IanB 6

Generating Log Archive Activity Histograms

A few weeks ago, Ember posted a tweet mentioning that being able to see a histogram showing frequency of transaction log archive activity would be helpful. I had already done some work in this area by parsing the diagnostic log file (db2diag.log) for log archive messages, but I thought I could throw together a quick example of how to do this using...

AprilFools 4

The Coming pureScale Invasion

I’ve thought for a long time that one of the biggest issues that IBM has faced in getting more traction with pureScale is that it’s only included in the Advanced editions of DB2 – Advanced Workgroup Server Edition and Advanced Enterprise Server Edition. The recent announcement of the Business Application Continuity Offering will help expand the pureScale footprint to even more...

IanB 2

Keeping EXPLAIN under control

Have you ever looked at a list of tables in your database, only to see the set of EXPLAIN tables present in two, five or even 10 different developers’ schemas? I don’t know about you, but this drives me crazy. Very few of the developers that I know pay attention to these tables, and many of them are not even...

5

A Tale of Two Connections

It was the best of times, it was the worst of times, it was the age of wisdom, it was the age of foolishness, it was the epoch of belief, it was the epoch of incredulity, it was the season of Light, it was the season of Darkness, it was the spring of hope, it was the winter of despair,...

1

Tips for Information on Demand Attendees

IBM’s Information on Demand 2013 Conference is less than a month away, and since I’ve been to this conference more times than I can remember (this will be Ember’s first IOD), she has asked me to write up something to help orient you to the conference and get the most out of it.   Conference Tips Try to build a...