List:General Discussion« Previous MessageNext Message »
From:Michael Widenius Date:June 29 1999 4:24am
Subject:Re: to much fragmentation
View as plain text  
>>>>> "Scott" == Scott Hess <scott@stripped> writes:

Scott> That (storing the blobs out to the filesystem) is the solution we're
Scott> currently pondering.  The main downside is that the database is being used
Scott> as the central "memory" for a system that involves a couple components, and
Scott> we'd _really_ rather not teach all components about the off-database blob
Scott> storage, if we can get away with it.

Scott> Does anyone have firm knowledge of the fragmentation differences between
Scott> doing updates and doing a full delete/insert?  I can imagine an
Scott> implementation where an update might re-use the currently allocated space,
Scott> so if the updated data is larger than the existing data, fragmentation is
Scott> going to be a problem.  But a delete followed by an insert may do better.
Scott> While we can do some measuring to see if this happens, but I'd like to know
Scott> the response of someone with deep knowledge of how MYSQL stores its data.

Hi!

Yes. MySQL 3.22 will fragment rows if you mix a lot of deletes/inserts into 
the same table.

The new ISAM in MySQL 3.23 will automaticly join adjacent deleted
blocks and can extend blocks much better than the old ISAM.

If you can wait a week, I would recommend testing MySQL 3.23 before
starting to hack the source!

Regards,
Monty
Thread
to much fragmentationDavid Johnson26 Jun
  • Re: to much fragmentationSasha Pachev27 Jun
  • Re: to much fragmentationScott Hess28 Jun
    • Re: to much fragmentationVivek Khera28 Jun
    • Re: to much fragmentationMichael Widenius29 Jun
      • Re: to much fragmentationEd Carp29 Jun
        • Re: to much fragmentationSasha Pachev29 Jun
        • Re: to much fragmentationMichael Widenius29 Jun
          • Authentication methodsRoger Smith29 Jun
            • Authentication methodsJani Tolonen1 Jul
        • Re: to much fragmentationScott Hess29 Jun
      • Re: to much fragmentationEd Carp29 Jun
        • Re: to much fragmentationMichael Widenius30 Jun
      • Re: to much fragmentationT├Ánu Samuel29 Jun
  • Re: to much fragmentationScott Hess28 Jun
Re: to much fragmentationFred Lindberg28 Jun