Re: INSERT SELECT LIMIT very very slow

[Mohammad Azmath]

As you are usning JOIN state it takes hell lot of time with below values;


Volume and indexes :
Table 1 : 2 000 000 rows (index : col1 and last_update)
Table 2 : 1000 rows (index : col1)

Server has to work on

Step 1)
2000000 * 1000 = 2000000000 Records

Step 2)
It has make temporay tables based on "ON" condition
(using index tables then to original tables

Step 3)

Then checks for "WHERE" conditions.


Solution for this could be Query without a join.
Try to work on SELF JOIN it helps


All the best :)