MySQL Bugs: #70836: ALTER IGNORE TABLE behavior

Bug #70836	ALTER IGNORE TABLE behavior
Submitted:	6 Nov 2013 16:02	Modified:	15 Nov 2013 18:41
Reporter:	Morgan Tocker	Email Updates:
Status:	Closed	Impact on me:	None
Category:	MySQL Server: Documentation	Severity:	S3 (Non-critical)
Version:	5.6.14	OS:	Any
Assigned to:	Paul DuBois	CPU Architecture:	Any

Description:
From: http://dev.mysql.com/doc/refman/5.6/en/alter-table.html

"IGNORE is a MySQL extension to standard SQL. It controls how ALTER TABLE works if there are duplicates on unique keys in the new table or if warnings occur when strict mode is enabled. If IGNORE is not specified, the copy is aborted and rolled back if duplicate-key errors occur. If IGNORE is specified, only the first row is used of rows with duplicates on a unique key. The other conflicting rows are deleted. Incorrect values are truncated to the closest matching acceptable value."

I wonder if we should use the wording "the first row", since SQL does not imply ordering.  InnoDB is somewhat deterministic, but I wonder if this could get users in trouble.

How to repeat:
--

Suggested fix:
"First row encountered", "picks a row" - I'm not sure.

Thank you for the report.

We certainly should explain what is "the first row" in this context.

Verified as described.

Thank you for your bug report. This issue has been addressed in the documentation. The updated documentation will appear on our website shortly, and will be included in the next release of the relevant products.

only the first row is used -> only one row is used