Category: DB2 Settings

4

Giving Automatic Maintenance a Fair Try

I’m a control freak. I think that control freaks tend to make good DBAs as long as they don’t take it too far. My position for years has been that I would rather control my runstats, reorgs, and backups directly than trust DB2’s automatic facilities. But I also try to keep an open mind. That means that every so often...

13

Quick Hit Tips – CPUSPEED, RESTRICTIVE, and DB2_WORKLOAD

Today we are going to talk about some random DB2 features that can’t stand in a blog of their own, but are worth discussing nonetheless. These are tidbits I had discovered during “DB2’s Got Talent” presentations, IDUG conferences, or “Hey, look what I discovered” moments. CPUSPEED (Database Management Configuration) You blow past this setting every time you execute “db2 get...

6

STMM Analysis Tool

I mostly like and use DB2’s Self Tuning Memory Memory Manager (STMM) for my OLTP databases where I have only one DB2 Instance/Database on a database server. I do have some areas that I do not let it set for me. I’ve recently learned about an analysis tool – Adam Storm did a presentation that mentioned it at IDUG 2014...

1

Informational Constraints – Benefits and Drawbacks

One of the most frustrating things a DBA can experience is troubleshooting due to bad data. The client is upset because rows are missing or incorrect data is returned.  The client facing web front end could be displaying gobilty-gook because the data retrieved makes no sense. Resources and energy are burned because of an issue is easily solved with the...

4

SQL5005C and Ulimit Issues

I’m spoiled. While we build a fair number of environments each year, we also have basic starting standards. Because of this, I sometimes miss the basics when a problem shows up. Or at least it takes me longer to get there. In this case, we had a couple of alerts over the high-volume weekend (Black Friday 2013). They were alerts...

2

HADR_TIMEOUT vs. HADR_PEER_WINDOW

It has taken me a while to fully understand the difference between HADR_TIMEOUT and HADR_PEER_WINDOW. I think there is some confusion here, so I’d like to address what each means and some considerations when setting them. In general, you’ll only need HADR_TIMEOUT when using HADR and only need HADR_PEER_WINDOW when using TSA(db2haicu) or some other automated failover tool. HADR_TIMEOUT HADR...

6

DB2 LUW – What is a Page?

The logical view of a database consists of the standard objects in any RDBMS – Tables, Indexes, etc. There are a number of layers of abstraction between this and the physical hardware level, both in the OS and within DB2. Setting the Page Size The smallest unit of I/O that DB2 can handle is a page. By default, the default...

4

When is ‘AUTOMATIC’ Not STMM?

Somewhere along the line, I associated ‘AUTOMATIC’ settings for parameters with DB2’s Self-Tuning Memory Manger (STMM). But the two are not associated. Sure, if STMM is set to ON, then some parameters set to AUTOMATIC will be tuned by the STMM, but many parameters can be set to automatic whether STMM is ON or not. What Parameters STMM can Change...