Quote:
Originally posted by tamilselvan
From the report, you should be in a position to understand why an object requires few extents. In the above example, I used "truncate" command. You can change it to any
other command as you like it. Ex: SELECT COUNT(*) FROM tablename;
The number of latches required for truncating a table that has few extents are very less than that of a table that has many extents.
Would someone be so kind and explain what kind of latches are required for performing "SELECT COUNT(*) FROM tablename;"???? What does latches have to do with the above statement???? So how can number of extents affect the performance of the selects?