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From Aaron Smuts <aasm...@wisc.edu>
Subject RE: Spooling after each update
Date Fri, 06 Jun 2003 12:35:53 GMT


> -----Original Message-----
> From: Vossberg, Michal [mailto:Michal.Vossberg@jamba-ag.de]
> Sent: Friday, June 06, 2003 5:28 AM
> To: 'Turbine JCS Users List'
> Subject: AW: Spooling after each update
> 
> Guys,
> 
> thanks for the insight. Aaron's suggestion works well, although now I
feel
> I
> have somewhat of a mixture, a cache that extends a disk cache but is
of
> type
> lateral. I think James has a good point moving the types into the
> configuration/construction.
> 

Yes, the type should be configurable.  That's simple.  We need to think
about whether we need another attribute or if we need to rename the
types. 

> > > How did you modify the disk cache to recover from a crash?
> 
> it doesn't recover, really. the only problem was the key file in case
it's
> not properly written, making the cache unusable after a restart.
Changing
> the indexed file to a flat file system with one file for each object
and
> writing the objects as soon as they were created is much more suitable
for
> us.

That isn't scalable.  You'd end up with thousands (or millions) of open
files, or you'd have to get try to check to see if it was there and then
open it.  That would be way too slow.  There are b-tree implementations
that will serve your purposes better.  Nothing like this could be nearly
as fast as the indexed disk cache.

An alternative would be to write the key file periodically.  It isn't
meant to be a database.  This might get you most of what you need.

> 
> > And when are we going to see all these neat changes people
> > keep talking about
> > as patches? ;)
> 
> :-) once we finished the inital version we are more than happy to
submit
> it
> as an additional plugin, in case it's wanted.
> 
> > > and then turn spooling off.  Type lateral auxiliaries are
> 
> I don't seem to be able to turn off spooling altogether. It doesn't
seem
> to
> be a cache attribute, rather an element attribute, but is not
considered!?
> What am I missing here?

You just don't configure a disk cache or you set it in the default
element attribute for the region.  If you do the first, then the second
is redundant and will just clutter your configuration.

Aaron




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