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Workload characterization using DBA_HIST tables and kSar

Been busy these past few days..

Well, this post is about taking advantage of the built in data store that started in 10gR1.. yeah it’s AWR, and it’s very much like a “Statspack on steroids” (got that from Kyle Hailey’s modules). What’s exciting about 10g and above is we could utilize the “Time Model” and the OSSTAT view and use them together with the SYSTAT view to have a far better workload information when going through all the SNAP_IDs.

I have this “little” issue before of getting lazy when generating multiple AWR reports… yeah it’s just so daunting, you’ll get tired just by generating those reports by hand and the catch is… you’ve not yet analyzed anything yet.. :p   (but yeah, you’re lucky if you’ve got access to the OEM performance page)

So.. I was thinking, if I get to see all the relevant workload info across SNAP_IDs it would be easier for me to notice trends and even possible for me to visualize the data, or even possible to do some statistics out of it.

On the Chapter 9 of Craig Shallahamer’s book (Oracle Performance Firefighting)… there he explained in detail what information you need to get for you to be able to define the Database Server’s Capacity, Requirements, and Utilization (U=R/C)…
I’ve outline some of the points here (see the Firefighting tab)

…. since the AWR report is based on DBA_HIST tables, I was able to make a script that shows the following:

1) CPU capacity – see image below, column 4 to 6
2) CPU requirements – see image below, column 7 to 14
3) Memory requirements – see image below, column 15
4) IO requirements – see image below, column 16 to 21
5) some SYSSTAT delta values – see image 22 to 23
6) Utilization – see image below, the last 6 columns

…. I’ve used the tables below for the query:

  • dba_hist_snapshot
  • dba_hist_osstat
  • dba_hist_sys_time_model
  • dba_hist_sysstat

Check out the scripts here:
For Linux/Unix: awr_genwl.sql
For Windows: awr_genwl_win.sql

IMPORTANT NOTE: Diagnostic Pack License is needed for the scripts, I’m updating my scripts frequently.. if the download link is not working here.. check out the Scripts Section for the file name and the most recent version of the script

Now time for some action! </p />
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