Bug #75910 Odd tablespace discard messages in error log
Submitted: 15 Feb 2015 21:00 Modified: 27 Feb 2015 19:14
Reporter: Roel Van de Paar (OCA) Email Updates:
Status: Verified Impact on me:
None 
Category:MySQL Server: InnoDB storage engine Severity:S1 (Critical)
Version:5.7.5-m15, 5.6.23 OS:Any
Assigned to: CPU Architecture:Any
Triage: Needs Triage: D3 (Medium)

[15 Feb 2015 21:00] Roel Van de Paar
Description:
mysql> show warnings;
+---------+------+---------------------------------------------+
| Level   | Code | Message                                     |
+---------+------+---------------------------------------------+
| Warning | 1812 | InnoDB: Tablespace is missing for table 't' |
+---------+------+---------------------------------------------+
1 row in set (0.00 sec)

> Error Log
2015-02-15T20:49:09.159878Z 1 [ERROR] InnoDB: Cannot delete tablespace 20 because it is not found in the tablespace memory cache.
2015-02-15T20:49:09.159899Z 1 [Warning] InnoDB: Cannot delete tablespace 20 in DISCARD TABLESPACE: Tablespace not found

How to repeat:
DROP DATABASE test;CREATE DATABASE test;USE test;
CREATE TABLE t (a INT) ENGINE=InnoDB;
ALTER TABLE t DISCARD TABLESPACE;
ALTER TABLE t DISCARD TABLESPACE;
SHOW WARNINGS;
[15 Feb 2015 21:05] Roel Van de Paar
2015-02-15T21:03:43.694265Z 2 [ERROR] InnoDB: Cannot delete tablespace 20 because it is not found in the tablespace memory cache.
2015-02-15T21:03:43.694297Z 2 [Warning] InnoDB: Cannot delete tablespace 20 in DISCARD TABLESPACE: Tablespace not found

1) Why the ERROR?
2) "tablespace 20" is non-descriptive/non-identifiable
[27 Feb 2015 19:14] Sveta Smirnova
Thank you for the report.

Verified as described.