[MDEV-27886] innodb temporay tablespace files are not shown correctly Created: 2022-02-18  Updated: 2022-05-10  Resolved: 2022-05-10

Status: Closed
Project: MariaDB Server
Component/s: Documentation, Storage Engine - InnoDB
Fix Version/s: N/A

Type: Task Priority: Major
Reporter: Oli Sennhauser Assignee: Ian Gilfillan
Resolution: Fixed Votes: 0
Labels: innodb, table, tablespace, temporary

Issue Links:
Relates
relates to MDEV-26782 InnoDB temporary tablespace: reclaimi... Closed
relates to MDEV-11426 Remove InnoDB INFORMATION_SCHEMA.FILE... Closed
relates to MDEV-22343 Remove SYS_TABLESPACES and SYS_DATAFILES Closed

 Description   

According to MariaDB documentation, this query:

https://mariadb.com/kb/en/innodb-temporary-tablespaces/

SELECT FILE_NAME AS "File Name",
INITIAL_SIZE AS "Initial Size",
DATA_FREE AS "Free Space",
TOTAL_EXTENTS * EXTENT_SIZE AS "Total Size",
MAXIMUM_SIZE AS "Max"
FROM information_Schema.FILES
;
Empty set (0.000 sec)

should show some results when using explicit temporary innodb tables:

create temporary table temp_random (
id bigint primary key,
random decimal not null
) engine = innodb;
insert into temp_random(id, random) select seq, rand() from seq_0_to_2000000;
drop temporary table temp_random;

but does not. Possibly related to: https://jira.mariadb.org/browse/MDEV-26782

 Comments   
Comment by Marko Mäkelä [ 2022-03-11 ]

I believe that INFORMATION_SCHEMA.FILES never returned anything for InnoDB in MariaDB. In MDEV-11426 the implementation that was added in MySQL 5.7 was intentionally removed. In MDEV-22343 (MariaDB 10.6.0) the implementation of INFORMATION_SCHEMA.INNODB_SYS_TABLESPACES and INFORMATION_SCHEMA.INNODB_SYS_DATAFILES was changed to return data straight from the memory. If those views do not cover the InnoDB temporary tablespace, it should be possible to add support (in MariaDB 10.6 or later).

In any case, the documentation is wrong if it really says that about INFORMATION_SCHEMA.FILES. It could be that the view always returns the empty result in MariaDB.

Comment by Ian Gilfillan [ 2022-05-10 ]

Example has been removed.

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