Category: Posts-By-Category

file000956896813 3

Backup Performance Investigation

While I have tuned backup performance before, it has often been through physical database changes (spreading tables across more table spaces) that I achieve my greatest results. This post is not about backup performance tuning, but about solving a specific backup duration mystery. The Problem A database that is about 330 GB backs up to Data Domain using a vendor...

Mountain_Md 1

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. Defining...

file0002050295530 0

Comparing Two Db2 Systems

Sometimes configuration needs to be kept in sync between two or more Db2 systems. There are a variety of reasons – sometimes this is for keeping two HADR servers in sync, and other times it may be for keeping a dev, QA, or Staging system in sync with production. In any case, having an idea of what needs to be...

file0002056368722 1

DB2 Temporary Table Spaces

What is Temp Space in Db2? Db2 needs some temporary space on disk to perform some actions. Commonly we think of these actions as primarily sort and join operations. These are operations where Db2 will first use the SORTHEAP memory area, but some data sets are just too big to fit in these locations. Even when an operation spills to...

file0001484079306 1

Db2 Basics: Levels of Configuration

Updated 11/22/2017: instructions on how to run the SQL statement There are a number of places where we can store and change configuration for a Db2 server. I wanted to walk through the main areas and a few details about them. Db2 Registry The Db2 registry actually has a number of levels within itself. It is accessed using the db2set...

6

DB2 Basics: Statement Terminators

The default statement terminator for DB2 on Linux, UNIX, and Windows platforms is the semi-colon (;). If you are executing a script of SQL using the -tf options, and do not specify an alternate terminator, DB2 will assume you are using the semi-colon. There are some statements that require semi-colons within the statements, though. For these kinds of statements, the...

1

Nothing Changed! A DB2 LUW Performance Investigation

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. Nothing Changed! Other times, everyone involved...