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From Geoff Howard <ghow...@crosswalk.com>
Subject RE: [RT]: Calculating the cache key
Date Wed, 22 May 2002 17:05:52 GMT
> 
> This (asynchron cache validation) won't help you speed up cache key
> manipulations. To get cached object validity, you must first 
> create (and
> calculate hash value of) the key, only then you can kick off
> asynchronous validation and serve content from the cache (if present).
> 
 
true, but only the first cached item (no dependencies) would be checked at
that time.  If you have 8 dependencies, you have cut the number of expensive
key generation and validation steps from at least 8 to 1.  

Currently the caching system is pessimistic - it assumes a cached item might
be invalid and has to check everything it depends on.  I am envisioning an
optimistic mode that acts first and thinks later.

> 
> You are right thinking that key generation in this scenario takes lots
> of time. If you comment out toString() method in the
> AggregatedCacheValidity, you could get as much as 50% speed 
> improvement
> for cached results - which means that yes, string manipulations take
> significant amount of time. 

50% improvement would be great, especially combined with reducing the number
of times that validity calculation has to happen.

> Berin's point is valid, fast cache will requires use of 
> compound integer
> or long keys.

I agree.

Geoff

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