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Re: 9243921c84b: Make all #sql temporary table names uniform


Hi, Michael!

On Apr 13, Michael Widenius wrote:
> revision-id: 9243921c84b (mariadb-10.5.2-128-g9243921c84b)
> parent(s): 8742d176bc2
> author: Michael Widenius <monty@xxxxxxxxxxx>
> committer: Michael Widenius <monty@xxxxxxxxxxx>
> timestamp: 2020-04-09 22:02:06 +0300
> message:
> Make all #sql temporary table names uniform
> The reason for this is to make all temporary file names similar and
> also to be able to figure out from where a #sql-xxx name orginates.
> New format is for most cases:
> #sql-name-current_pid-thread_id[-increment]
> Where name is one of subselect, alter, exchange, temptable or backup
> The execptions are:

typo, "exceptions"

> ALTER PARTITION shadow files:
> #sql-shadow-'original_table_name'

Please, add a thread_id here at the end. normally MDL should ensure that
no two threads can have a shadow for the same table at the same time,
but we have enough bugs as it is to introduce another vector when two
threads can overwrite each other temp files.

> Names from the temp pool:
> #sql-name-current_pid-pool_number

Would you mind if I drop temp pool completely in 10.5?
It was added by Jeremy in January 2001 with the comment

  Added --temp-pool option to mysqld.  This will cause temporary files
  created to use a small set of filenames, to try and avoid problems
  in the Linux kernel.

And I doubt it's still an issue in 2020.

VP of MariaDB Server Engineering
and security@xxxxxxxxxxx

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