MySQL Bugs: #34354: Feature request: EXPLAIN ALTER TABLE

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

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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

Thank you for a reasonable feature request.

A duplicate of this bug:
Bug #80793 	EXTEND EXPLAIN to cover ALTER TABLE