Bug #89175 Document name of generated hidden cluster index
Submitted: 10 Jan 2018 19:46 Modified: 23 Jan 2018 13:19
Reporter: Geoff Montee Email Updates:
Status: Closed Impact on me:
None 
Category:MySQL Server: Documentation Severity:S3 (Non-critical)
Version:5.6, 5.7 OS:Any
Assigned to: CPU Architecture:Any
Tags: documentation, innodb

[10 Jan 2018 19:46] Geoff Montee 
Description:
The documentation contains the following note:

"If the table has no PRIMARY KEY or suitable UNIQUE index, InnoDB internally generates a hidden clustered index on a synthetic column containing row ID values. The rows are ordered by the ID that InnoDB assigns to the rows in such a table. The row ID is a 6-byte field that increases monotonically as new rows are inserted. Thus, the rows ordered by the row ID are physically in insertion order."

https://dev.mysql.com/doc/refman/5.7/en/innodb-index-types.html

I know that this generated hidden cluster index is called `GEN_CLUST_INDEX`, but it is a bit odd that the documentation doesn't specify that. It should probably mention it, so that users can find this documentation page if they see `GEN_CLUST_INDEX`, such as in SHOW ENGINE INNODB STATUS output or in deadlock messages in the error log.

How to repeat:
N/A

Suggested fix:
Add a sentence to the relevant documentation page that specifies that this index is called `GEN_CLUST_INDEX`.
[11 Jan 2018 5:51] MySQL Verification Team 
Hello Geoff Montee,

Thank you for the report and feedback.

Thanks,
Umesh
[23 Jan 2018 13:19] Daniel Price 
Posted by developer:
 
The referenced page was updated with the name of the generated clustered index. The updated content should appear online soon.

Thank you for the bug report.