Streaming development

Martin Blix Grydeland martin at
Thu Oct 6 10:21:11 CEST 2011

Hi Thomas,

Range requests and streaming are right now mutually exclusive features. If a
range request comes in, it will loose it's do_stream flag. I am working on
enabling the range support on streaming requests, and for the streaming case
this means the clients will receive the range bytes at the time they become
available on the stream (backend request still asks for the whole object). I
hope to have something finished for this within a couple of weeks.

Allowing range requests against the backend and populating the cache from
those bits is not something we are working on right now. It would then
require ETAGs matching to guard against the backend object being altered
over the life time of the cached object, and will require some heavy
thinking to get right. We might look into doing this some time, but it is
not in the plans right now.

Martin Blix Grydeland

On Tue, Oct 4, 2011 at 18:10, Thomas SOUVIGNET <
thomas.souvignet at> wrote:

> Hi,
> Your work on the streaming features for varnish is great but I have a
> little problem using it for range caching. Is it possible for HTTP range
> requests to use the cache while the file was entirely cached ? How about
> when it is being retrieved and cached at the same time ? Is it possible to
> populate the cache just with range requests (ie. a file goes from 0 to 500,
> one client asks for 0-200, another one for 200-400 and another one for
> 400-500 and each request will be used to have the file entirely or partially
> cached while the requests are being served) ?
> Thanks for your work. And thanks in advance for your answer.
> --
> Thomas SOUVIGNET, R&E Engineer
> SmartJog SAS - - A TDF Group Company
> Office: 27, blvd Hippolyte Marques 94200 Ivry-sur-Seine - France EU
> Phone: +33 (0)1 5868 6207

Martin Blix Grydeland
Varnish Software AS
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