Skip to content

Author Archives Tanel Poder

Which number takes more space in an Oracle row?

So, which number takes more bytes inside an Oracle row? A: 123 B:  1000000000000000000000000000000000000 And the correct answer is … (drumroll) … B! The “big” number 1000000000000000000000000000000000000 actually takes less space than the “small” 123! Let’s verify this: SQL> select vsize(123) A, vsize(1000000000000000000000000000000000000) B from dual; A B ———- ———- 3 2 WTF? Why does such [...]

Posted 02 September 2010 § Uncategorized ‡ Comments Off °

Public appearances 2010

Here’s the list of events where I’ll speak this year: Michigan OakTable Symposium 2010 Ann Arbor, MI 16-17 September 2010 Considering the concentration of OakTable members there, this will be an awesome event! I will be delivering my “Back to Basics: Choosing The Entry Point to Performance Troubleshooting Wisely” and “Understanding LGWR, log file sync [...]

Posted 01 September 2010 § Uncategorized ‡ Comments Off °

Quiz: Explaining index creation

Did you know that it’s possible to use EXPLAIN PLAN FOR CREATE INDEX ON table(col1,col2,col3) syntax for explaining what exactly would be done when an index is created? That’s useful for example for seeing the Oracle’s estimated index size without having to actually create the index. You can also use EXPLAIN PLAN FOR ALTER INDEX [...]

Posted 23 April 2010 § Uncategorized ‡ Comments Off °