Bug #34354 Feature request: EXPLAIN ALTER TABLE
Submitted: 6 Feb 2008 17:04 Modified: 6 Feb 2008 19:32
Reporter: Paul DuBois Email Updates:
Status: Verified Impact on me:
None 
Category:MySQL Server: DDL Severity:S4 (Feature request)
Version:5.1 OS:Any
Assigned to: CPU Architecture:Any

[6 Feb 2008 17:04] Paul DuBois
Description:
In MySQL 5.1, work was done to make some ALTER TABLE operations faster, with no need for a temporary table (such as changes that affect only metadata), as described here:

http://dev.mysql.com/doc/refman/5.1/en/alter-table.html

However, a user cannot tell in advance whether a given operation will be fast or not, and thus must actually execute ALTER TABLE and hope that it will be fast.

An EXPLAIN-style statement would be useful for ALTER TABLE. I envision that EXPLAIN ALTER TABLE would provide information to the user that would indicate the "cost" of a given alteration.

How to repeat:
N/A
[6 Feb 2008 19:32] Valeriy Kravchuk
Thank you for a reasonable feature request.
[18 Oct 2016 8:51] Daniƫl van Eeden
A duplicate of this bug:
Bug #80793 	EXTEND EXPLAIN to cover ALTER TABLE