What is "OVERHEAD" in SQL?

[s3nzo]

Well i googled it and answers i got were how to solve this and that it slows down database response so i did optimize tables but i still would like to know what OVERHEAD is and what causes it? if anyone knows

[amylee]

it's just temporary that mysql uses to store data in, just optimize your database and will dissapear

[arnage]

Idea...

mysql_query("DELETE FROM `table` WHERE `bla` = '".$bla."'");
echo 'Deleted something!';
mysql_query("OPTIMIZE TABLE `table`"); 

Or use this as an option: optimize-all-tables-in-a-mysql-database