Bug #96934 innodb_undo_tablespaces* status metrics are not documented
Submitted: 18 Sep 2019 15:11 Modified: 24 Sep 2019 17:50
Reporter: Tibor Korocz Email Updates:
Status: Closed Impact on me:
None 
Category:MySQL Server: Documentation Severity:S3 (Non-critical)
Version:8.0.17 OS:Any
Assigned to: CPU Architecture:Any

[18 Sep 2019 15:11] Tibor Korocz
Description:
In MySQL 8 we have new status metrics:

mysql [localhost:8017] {msandbox} ((none)) > show global status like 'innodb_undo_tablespaces%';
+----------------------------------+-------+
| Variable_name                    | Value |
+----------------------------------+-------+
| Innodb_undo_tablespaces_total    | 2     |
| Innodb_undo_tablespaces_implicit | 2     |
| Innodb_undo_tablespaces_explicit | 0     |
| Innodb_undo_tablespaces_active   | 2     |
+----------------------------------+-------+
4 rows in set (0.00 sec)

They are not documented, luckily the source code give use explanation:

  ulint innodb_undo_tablespaces_total;    /*!< total number of undo tablespaces
                                          innoDB is tracking. */
  ulint innodb_undo_tablespaces_implicit; /*!< number of undo tablespaces
                                          innoDB created implicitly. */
  ulint innodb_undo_tablespaces_explicit; /*!< number of undo tablespaces
                                          the dba created explicitly. */
  ulint innodb_undo_tablespaces_active;   /*!< number of active undo
                                          tablespaces */

How to repeat:
No need to repeat it is a documentation issue.

Suggested fix:
Update the documentation.
[18 Sep 2019 15:31] Miguel Solorzano
Thank you for the bug report.
[24 Sep 2019 17:50] Daniel Price
Posted by developer:
 
The status variables were added to the documentation. The changes should appear online soon.

https://dev.mysql.com/doc/refman/8.0/en/innodb-undo-tablespaces.html
https://dev.mysql.com/doc/refman/8.0/en/server-status-variables.html

Thank you for the bug report.