Re: Header Table and Static Table Indicies Switched

On 3 August 2014 01:55, Jeff Pinner <jpinner@twitter.com> wrote:

> Looking at request on an internal upload API that 12 internal header
> fields:
>
> On the first request I measure no change in compression efficiency
> (not surprising as all header names are unique so nothing is being
> reused).
>
> On the second request I measure a size reduction of 8% when switching
> the header table to occur before the static table.
>


Is that 8% relative to just the second request?

The percentages I have been reporting have been relative to to the entire
data stream of all requests, so if comparing your 8% to the numbers I've
quoted, then it should be much less < 8%.     I'm not saying that is not a
valid way to report compression, I'm just making sure we don't compare
apples with oranges.

Also, I don't doubt that there are usage patterns for each index ordering
will be better or worse.  The question is, are such examples widely
representative?      We are never going to find a perfect compression that
is one-size fits all and whilst we are looking at compression savings of
60-70%, I think that any variation that is +/- <8% for particular data sets
is pretty much down among the noise!

cheers




-- 
Greg Wilkins <gregw@intalio.com>
http://eclipse.org/jetty HTTP, SPDY, Websocket server and client that scales
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