[Varnish] #584: Backend probing half-close issue
Varnish
varnish-bugs at projects.linpro.no
Thu Nov 19 12:34:48 CET 2009
#584: Backend probing half-close issue
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Reporter: phk | Owner: phk
Type: defect | Status: new
Priority: normal | Milestone:
Component: varnishd | Version: trunk
Severity: normal | Keywords:
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There seems to be no clear answer to when/if it is allowed to half-close a
TCP connection when doing a request: After the request is sent or after
the response has been received.
Good cases can be made for both scenarios, but the first fails on some
backends, whereas the second works on all.
The varnish backend probe uses the first method, in an attemt to be able
to figure out if the backend has ACK'ed the request or not.
Given that the request is almost guaranteed to fit inside the first
window, only very deficient TCP stacks will not ACK the request
unconditionally, so this test is worthless.
We should switch to the second method, and do a full close, after the poll
response has been received.
--
Ticket URL: <http://varnish.projects.linpro.no/ticket/584>
Varnish <http://varnish.projects.linpro.no/>
The Varnish HTTP Accelerator
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