MySQL Bugs: #96440: ENUM support in online DDL section is unclear

Bug #96440	ENUM support in online DDL section is unclear
Submitted:	6 Aug 2019 15:09	Modified:	6 Sep 2019 16:38
Reporter:	Rolf Martin-Hoster	Email Updates:
Status:	No Feedback	Impact on me:	None
Category:	MySQL Server: Documentation	Severity:	S3 (Non-critical)
Version:		OS:	Any
Assigned to:	MySQL Verification Team	CPU Architecture:	Any

Description:
https://dev.mysql.com/doc/refman/5.7/en/innodb-online-ddl-operations.html#online-ddl-colum...

States :

Modifying the definition of an ENUM or SET column by adding new enumeration or set members to the end of the list of valid member values may be performed in place, as long as the storage size of the data type does not change. For example, adding a member to a SET column that has 8 members changes the required storage per value from 1 byte to 2 bytes; this requires a table copy. Adding members in the middle of the list causes renumbering of existing members, which requires a table copy.

But it does not clarify that reording an ENUM is also blocking.

How to repeat:
N/A

Suggested fix:
Clarify that is or is not blocking when re-ordering an enum.

Hi,

Thanks for the report. Now I need more data to understand it :D

What do you mean by blocking here?

We have in the documentation

- in table we state that concurrent DML's are possible (so not blocking nothing)
- in the text below we give bit more description:

[quote]
Modifying the definition of an ENUM or SET column by adding new enumeration or set members to the end of the list of valid member values may be performed in place, as long as the storage size of the data type does not change. For example, adding a member to a SET column that has 8 members changes the required storage per value from 1 byte to 2 bytes; this requires a table copy. Adding members in the middle of the list causes renumbering of existing members, which requires a table copy. 
[/quote]

Only thing I'd change here is, maybe, add a * for "In Place", and "Rebuilds Table". Is that what you are referring to or?

thanks
Bogdan

No feedback was provided for this bug for over a month, so it is
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