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January 2008

Expensive calculator…

Oracle has evolved over time to much more than just a plain relational database. One option is to use Oracle as an expensive calculator.
When researching or demoing Oracle, it’s quite convenient to do number calculations directly on sqlplus prompt, especially if dealing with internals where lots of stuff is about addresses and offsets shown in hex.
Here’s the script what I use for such purposes: https://github.com/tanelpoder/tpt-oracle/blob/master/calc.sql.
It usually saves me couple of seconds every calculation as I don’t have to reopen the calc.

Why does Oracle parameter count change during session lifetime?

I was once asked a question, why does Oracle change its parameter count during session lifetime?

The question arose from the following observation that v$parameter shows more parameters after you adjust some hidden parameter value:

SQL>
SQL> select count(*) from v$parameter;

  COUNT(*)
----------
       288

SQL>
SQL> alter session set "_complex_view_merging"=false;

Session altered.

SQL> select count(*) from v$parameter;

  COUNT(*)
----------
       289

Looks like the parameter count was just increased by one!

“It sure seems like the hidden parameter don’t exist before they are actually modified”:

Why does Oracle parameter count change during session lifetime?

I was once asked a question, why does Oracle change its parameter count during session lifetime?

The question arose from the following observation that v$parameter shows more parameters after you adjust some hidden parameter value:

SQL>
SQL> select count(*) from v$parameter;

  COUNT(*)
----------
       288

SQL>
SQL> alter session set "_complex_view_merging"=false;

Session altered.

SQL> select count(*) from v$parameter;

  COUNT(*)
----------
       289

Looks like the parameter count was just increased by one!

“It sure seems like the hidden parameter don’t exist before they are actually modified”:

Why does Oracle parameter count change during session lifetime?

I was once asked a question, why does Oracle change its parameter count during session lifetime?

The question arose from the following observation that v$parameter shows more parameters after you adjust some hidden parameter value:

SQL>
SQL> select count(*) from v$parameter;

  COUNT(*)
----------
       288

SQL>
SQL> alter session set "_complex_view_merging"=false;

Session altered.

SQL> select count(*) from v$parameter;

  COUNT(*)
----------
       289

Looks like the parameter count was just increased by one!

“It sure seems like the hidden parameter don’t exist before they are actually modified”:

Why does Oracle parameter count change during session lifetime?

I was once asked a question, why does Oracle change its parameter count during session lifetime?

The question arose from the following observation that v$parameter shows more parameters after you adjust some hidden parameter value:

SQL>
SQL> select count(*) from v$parameter;

  COUNT(*)
----------
       288

SQL>
SQL> alter session set "_complex_view_merging"=false;

Session altered.

SQL> select count(*) from v$parameter;

  COUNT(*)
----------
       289

Looks like the parameter count was just increased by one!

“It sure seems like the hidden parameter don’t exist before they are actually modified”:

Systematic application troubleshooting in Unix

How many times have you seen a following case, where a user or developer complains that their Oracle session is stuck or running very slowly and the person who starts investigating the issue does following:

  1. Checks the database for locks
  2. Checks free disk space
  3. Checks alert log
  4. Goes back to the client saying “we did a healthcheck and everything looks ok” and closes the case or asks the user/developer to contact application support team or tune their SQL

The point here is that what the heck do the database locks, alert log or disk space have to do with first round session troubleshooting, when Oracle provides just about everything you need in one simple view?

Systematic application troubleshooting in Unix

How many times have you seen a following case, where a user or developer complains that their Oracle session is stuck or running very slowly and the person who starts investigating the issue does following:

  1. Checks the database for locks
  2. Checks free disk space
  3. Checks alert log
  4. Goes back to the client saying “we did a healthcheck and everything looks ok” and closes the case or asks the user/developer to contact application support team or tune their SQL

The point here is that what the heck do the database locks, alert log or disk space have to do with first round session troubleshooting, when Oracle provides just about everything you need in one simple view?

Systematic application troubleshooting in Unix

How many times have you seen a following case, where a user or developer complains that their Oracle session is stuck or running very slowly and the person who starts investigating the issue does following:

  1. Checks the database for locks
  2. Checks free disk space
  3. Checks alert log
  4. Goes back to the client saying “we did a healthcheck and everything looks ok” and closes the case or asks the user/developer to contact application support team or tune their SQL

The point here is that what the heck do the database locks, alert log or disk space have to do with first round session troubleshooting, when Oracle provides just about everything you need in one simple view?

Systematic application troubleshooting in Unix

How many times have you seen a following case, where a user or developer complains that their Oracle session is stuck or running very slowly and the person who starts investigating the issue does following:

  1. Checks the database for locks
  2. Checks free disk space
  3. Checks alert log
  4. Goes back to the client saying “we did a healthcheck and everything looks ok” and closes the case or asks the user/developer to contact application support team or tune their SQL

The point here is that what the heck do the database locks, alert log or disk space have to do with first round session troubleshooting, when Oracle provides just about everything you need in one simple view?

Loading xml files with xml db

A tutorial on loading XML files into relational tables. March 2006