Moin Mark,
reading your post I actively ignored the tmpfs-thing, sorry.
The general question about the way PBXT uses file-system-cache still
stays (for me).
erkan
btw: It "hard" to comment if not in facebook:)
On Fri, Mar 19, 2010 at 10:17:00AM -0700, MARK CALLAGHAN wrote:
I don't think so. I think all engines were dependent to a similar
degree on tmpfs and nothing go to use the OS buffer cache.
AFAIK, tmpfs files are not doubled-buffered in the OS buffer
cache. I
think I learned this from reading lkml, but I don't mind citations
that state otherwise.
So, each fetch of a MyISAM row must get all columns and read from
the
file after doing the primary key index lookup that is likely to
hit in
the key cache.
InnoDB is should do reads from tmpfs for most queries as the table
data doesn't fit in the InnoDB buffer cache.
I only set two of the my.cnf settings for PBXT and don't know if
that
was sufficient to keep it from caching too much.
On Fri, Mar 19, 2010 at 9:13 AM, erkan yanar <erkan.yanar@xxxxxxxxxxxxx
> wrote:
Moin,
I enjoy it seeing PBXT gaining more publicity \o/
(http://www.facebook.com/note.php?note_id=378043115932)
I wonder if PBXT benefits as much as MyISAM from filesystemcache?
Reading the post I think MyISAM is better configured on that
machine
than InnoDB, because MyISAM benefits a lot from the
filesystemcache.
And now I wonder about best practice for PBXT.
regards
erkan
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