Date: Sun, 23 Jun 2002 11:40:53 -0700 (PDT) From: Matthew Dillon <dillon@apollo.backplane.com> To: freebsd-stable@freebsd.org Subject: INN/Diablo and Postgres/Mysql/etc performance heads up Message-ID: <200206231840.g5NIerSq086779@apollo.backplane.com>
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This is just a heads up to people who use INN/Diablo (USENET news
feed systems), or postgres/mysql (database systems) in heavily
loaded environment. I recently MFC'd a major fix to a performance issue
that was accidently introduced in late 2000. A security fix had the
unintended (and not-noticed-enough at the time) side effect of creating
a severe loss in performance in the file block rewrite case, i.e.
writing into the middle of a previously created file. (appending to
a file is unaffected, performance remains good for that case).
This case has just been fixed. I wish I could take credit but I was
responsible for the original commit that created the problem in the
first place :-(
In anycase, the performance issue only effects the rewrite case which
means it will tend to only effect database applications (and then only
under write loads), and newsfeed applications (aka INN cyclic buffers).
Write performance for such applications should improve between 2x and 10x.
Yes, that's what I said(!). I've gotten verification from a number of
sources (two sources running INN and one running postgresql).
Maybe we'll win some benchmark tests now <GRIN>.
The fix is 1.65.2.11 of src/sys/ufs/ufs/ufs_readwrite.c, in -STABLE.
It did not make it into the release nor is it in the security branch.
I strongly recommend that people running these sorts of applications
who intend to upgrade to 4.6-REL anyway also upgrade their kernel to
the latest -stable after completing the initial upgrade to 4.6-REL.
-
Also this is a good time to remind people running Apache as of
4.6-RELEASE that they should upgrade to the latest in ports, due to
an exploit that was found just after we rolled the release. The Apache
in the 4.6-REL package/ports set is exploitable. Be careful to backup
your /usr/local/www before installing. (this is the same exploit that
has been discussed on the lists already. If you have already upgraded
your Apache you should be fine).
Thanks,
-Matt
Matthew Dillon
<dillon@backplane.com>
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