Oracle Data Dictionary

I just read an article from Oracle Magazine on the data dictionary views. There was a figure with 12 different user views of interest. I am trying to digest all the information and make some connections between the views. Let's start with USER_SOURCE. Okay I have employed that one before. It can tell you the source code of something you have compiled into the database, such as a stored procedure.

Now an object you compile into the database will also have an entry in USER_OBJECTS. That is also familiar territory. But there is also a USER_OBJECT_SIZE view. I bet you can figure out what that view tells you. Now other views hold object information of a certain kinds. Your triggers are shown in USER_TRIGGERS, and your procedures in USER_PROCEDURES. But have you ever heard of the view USER_TRIGGERS_COLS? Me neither. Looks like it maps triggers to the table/columns they use.

I have never queried USER_ERRORS directly. I just type SHOW ERRORS in SQL*Plus. To do some source code analysis, it looks like I might check out USER_DEPENDENCIES, USER_ARGUMENTS, or USER_IDENTIFIERS. Looks like I got some homework to do. If I find anything of use, I will definitely share it.

Performance Views

I recently read an good article in Oracle Magazine about the fundamentals of performance tuning. Actually it was almost an introduction to tuning. I already knew about the V$SESSION view that tells you what your session is waiting for. However I discovered there is also a V$SESSION_EVENT view as well. This view is a history of waits that your session has encountered over its lifetime. Now that is some good stuff. The view itself is small. There are not that many columns. But you can get a lot of data by quering it.

I had heard about the V$SESSTAT view before. But I had not used it before and did not even know how to use it. This important view will help you determine what resources are being used. Yessir good stuff. You should really check out the Artical in the Nov/Dev 2012 Oracle magazine. Perhaps it is online somewhere. The title was "Beginning Performance Tuning: Diagnose the Past". Good luck peeps.