Bug #43083 very large file setting generated by configuration wizard
Submitted: 21 Feb 2009 21:43 Modified: 24 Feb 2009 19:40
Reporter: Peter Laursen (Basic Quality Contributor) Email Updates:
Status: Closed Impact on me:
Category:MySQL Server: Installing Severity:S3 (Non-critical)
Version:5.0.77 + 5.1.31 OS:Any
Assigned to: CPU Architecture:Any
Tags: qc

[21 Feb 2009 21:43] Peter Laursen
I have done a fresh install of above mentioned servers on a new system using the config wizard on Windows defining a 'developer machine' configuration.

I notice this in the my.ini generated by the wizard:

#*** MyISAM Specific options

# The maximum size of the temporary file MySQL is allowed to use while
# recreating the index (during REPAIR, ALTER TABLE or LOAD DATA INFILE.
# If the file-size would be bigger than this, the index will be created
# through the key cache (which is slower).

How to repeat:
see above

Suggested fix:
100G for a 'developer machine'. Serious?
[23 Feb 2009 8:12] Valeriy Kravchuk
Thank you for the problem report.
[23 Feb 2009 8:23] Daniel Fischer
This is not a bug. All this does is set an upper bound for a temporary file that is used very rarely. Mysqld will not attempt to use more disk space than available. The file will be removed immediately after recreating the index.
[23 Feb 2009 8:55] Peter Laursen
I open again.  Not because I do not accept the answer and not to make trouble!

But what is the idea then in having such variable at all if all free disk space should be allowed to be used?
[23 Feb 2009 8:59] Daniel Fischer
Please stop re-opening bugs.
[24 Feb 2009 19:07] Sergei Golubchik
I suppose on a 'developer machine' you can allow mysqld to use all the available free space to rebuild the table, you aren't supposed to run many mission-critical applications there that will be impacted by that.

And 100G isn't that much, that was pretty standard HD size three years ago, now it's pretty much entry-level.
[24 Feb 2009 19:40] Peter Laursen
I *never* had a proper reply to my question what the idea is to apply a setting that will practically never have any effect at all. Then better leave it out! Putting such setting in a configuration file is simply pollution in my opinion!  Why not 500 GB (I just bought a 1 TB disk actually - it will be the standard from this summer - but also this is completely irrelevant! We are discussing server configuration - not hardware trends!).  But with next server release the wizard will raise setting from 100 GB to something more 'timy' I understand?!

And if such setting really is important why is there then absolutely no setting for that variable in the 'my.ini'/'my.cnf' (my-medium, 'my-large' etc.) templates shipping with the server?

I never claimed that this was an important issue.  It was marked as S3 category.  I am trying to help, improve and suggest actually. But the prompt (and what I experienced as arrogant) response really surprised me.