[Varnish] #1090: Latency for streaming using byte range requests
Varnish
varnish-bugs at varnish-cache.org
Mon Feb 6 12:59:51 CET 2012
#1090: Latency for streaming using byte range requests
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Reporter: helmer | Type: enhancement
Status: closed | Priority: normal
Milestone: | Component: varnishd
Version: 3.0.2 | Severity: normal
Resolution: invalid | Keywords:
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Changes (by martin):
* status: new => closed
* resolution: => invalid
Comment:
In Varnish 3.0.2s, when a range request is made, the do_stream flag is
turned off. So the request becomes just like a normal range request
without any streaming. That is probably the cause of the latency you are
experiencing, where the entire object will have to be fetched into Varnish
before the range request can be delivered to the client.
When the streaming support is released in the main branch of Varnish, we
plan on having range support for the requests also when doing streaming
delivery. This will then mean that the requesting client will have a
streaming delivery of the requested range as the bytes of this range
becomes available in the cache. The backend(/origin) request will still be
for the full object.
There is a patch available for the Varnish 3.0S that was posted on the
varnish-dev mailing list some time ago by Thomas Souvignet that implements
this mode as well.
Your requested feature of byte range requests against the origin server is
not something that is being worked on, as this would require support for
partial objects which Varnish doesn't have. So Varnish will continue to
request the full object from the origin also when streaming.
As this is a feature request and we only use trac for bugs, I will close
this ticket.
Regards,
Martin Blix Grydeland
--
Ticket URL: <https://www.varnish-cache.org/trac/ticket/1090#comment:1>
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