Question

I am using MySQl , I have a table named cars which is in my dev_db database.

I inserted about 6,000,000 data into the table (That’s a large amount of data insertion) by using bulk insertion like following:

INSERT INTO cars (cid, name, msg, date) 
VALUES (1, 'blabla', 'blabla', '2001-01-08'),
       (11, 'blabla', 'blabla', '2001-11-28'), 
       ... ,
       (3, 'blabla', 'blabla', '2010-06-03');

After this large data insertion into my cars table

I decide to also optimize the table like following:

OPTIMIZE TABLE cars;

I waited 53min for the optimization, finally it is done and mysql console shows me the following message:

The Msg_text shows me this table does not support optimize… , which makes my brain yields two questions to ask :

1. Does the mysql message above means the 53min I waited actually did nothing useful??

2. is it necessary to optimize my table after large amount data insertion? and why?

Answer 1

Optimize is useful if you have removed or overwritten rows, or if you have changed indexes. If you just inserted data it is not needed to optimize.

The MySQL Optimize Table command will effectively de-fragment a mysql
table and is very useful for tables which are frequently updated
and/or deleted.

Also look here: http://www.dbtuna.com/article.php?id=15