The original design worked from the data itself and it's dev supplied
hashes.
This was broken.
1- Slow
2- prone to cache misses
Think of fastKey as the equivalent of a RDBMS generated primary key,
something the engine knows how to work with really fast. So instead of
relying on the user supplied key based on the fields of the object we use
the fastKey.
As in JDBC instead of saying
select * where variable1=bla variable2=bla variable3=bla variable4 = bla
we say
select * where fastKey= bla
also the second one based on hash is unbreakable, doesn't depend on the
developer supplied implementation.
To give credit to Dan OConnor, it still remains that if hash and equals are
f*cked up the stuff will still break (on *multiple* findByPK most notably,
we no way around this) but at least create and direct findByPK are *assured*
to work properly on subsequent cache lookups.
at's all
marc
> -----Original Message-----
> From: [EMAIL PROTECTED]
> [mailto:[EMAIL PROTECTED]]On Behalf Of Jay Walters
> Sent: Friday, August 18, 2000 6:03 AM
> To: jBoss Developer
> Subject: RE: [jBoss-Dev] what is fastCache
>
>
> Ok, I read your e-mail. What exactly is being cached? You talk both of
> lookup of keys (as if they're cached) and internal generation of
> keys. Can
> you provide some more information?
>
> Cheers
>
> -----Original Message-----
> From: marc fleury [mailto:[EMAIL PROTECTED]]
> Sent: Thursday, August 17, 2000 4:28 PM
> To: jBoss Developer; jBoss
> Subject: [jBoss-Dev] what is fastCache
>
>
> fastCache is a robust and extremely fast implementation of data caching in
> jboss.
>
> it works from its own internally generated keys to speed up the lookup and
> operations (think of it as the db generated primarykey really only in the
> webOS layer).
>
> FastCache is lenient, say you screw up hash and equals, he won't be
> unsettled.
> But his true purpose it to allow fast and robust lookup of keys, something
> that did not exist previously (well did in jboss1.0).
>
> The changes are deeper than I thought, which goes to prove that the cache
> structures are pervasive in a container :))). And that's it, it compiles,
> but it isn't fully debugged, I will try to do that asap
>
> regards
>
> marc
>
> PS: we post a new binary :))))
>
> ________________________
> Marc Fleury
> Chief Technology Officer
> Telkel, Inc.
> ________________________
>
>
>
