How Db2 Handles SQL SQL is a powerful language in the hands of the right RDBMS. One of SQL's strengths is that you specify what data you want returned without specifying what file, disk, san, or sector that data is stored on. Because we describe the result set we...
Indexes are Good for Performance Generally speaking, DBAs and developers spend a fair amount of their performance time trying to find which indexes to add to a database to improve performance. If a specific query is having performance problems, one of the strongest...
My top metric for analyzing database performance is index read efficiency. This metric essentially shows how well indexed a database is for the workload that runs against it. Index read efficiency is calculated by taking the rows read and dividing them by the rows...
What is Runstats? Runstats is a utility in Db2 that is used to collect statistics about the data in Db2 tables and indexes. This statistical information is critical to Db2 database performance. Runstats is executed on a table by table basis, so scripting it is quite...
Personally, I am biased. As the team lead for Db2 services here at XTIVIA, I think Db2 and other enterprise database software have significant advantages over some of the open source or free options out there. Decades of time invested and spent solving the problems of...
Sometimes when you're looking at Db2 Queries, you may notice question marks in your queries, like this: SELECT partnum, sum(quantity) as QUANTITY FROM orderitems oi INNER JOIN orders o ON oi.orders_id = o.orders_id where o.field3 is null and o.timeplaced is not null...
Ahhhhhh—the fresh smell of a brand new laptop, being pulled out of its box for the first time. Breathe it in. Your tax return really paid off this year, but your shopping doesn’t end with this new device. On the contrary, you’ve got a spree ahead of you. This laptop...
Most Db2 DBAs administer Db2 at the command line. The command line provides a rich and powerful interface with Db2, and has a lot of options. Many other users may wish to access Db2 at the command line as well. Developers and system administrators are just a few of...
What is db2prereqcheck? db2prereqcheck is a tool IBM provides to check for all OS and software prerequisites prior to and during the installation of Db2. It is included with every fixpack and base code that Db2 provides. When to use db2preqcheck Use db2prereqcheck...
The row size for a table in Db2 is important in several ways. It determines which page size can be used for a tablespace, and it can help us estimate table size - either optimal or future. Selecting a Page Size Db2 page sizes are adjustable only for tablespace and...