Evan,

In my lab testing, I've noticed inconsistent results with the
collapsed_forwarding plugin.  Sometimes it leaks redirects to the
client. Sometimes it sends a 500-Ink_Api response back.
However, when increasing open_write retires to some value to allow
upstream to respond, my results have been more consistent.. Where
instead of error responses being sent back downstream, I
am now sending 200s(or something other than a 5xx).

proxy.config.http.cache.max_open_write_retries 50

So whats the difference with core waiting for the write lock to free
up, as opposed to handing off the same to the plugin ?






On Tue, Jun 19, 2018 at 10:07 AM, [email protected]
<[email protected]> wrote:
> I believe the ats params provide good enough protection except for the one 
> specific case mentioned in the collapsed forwarding plugin docs. The one case 
> they can't protect against is multiple instantaneous hits for the same 
> content. So this actually comes up fairly often for linear video since you 
> have multiple clients that can all be requesting the same video chunk at the 
> same time
>
> On 2018/06/19 12:24:08, Jeremy Payne <[email protected]> wrote:
>> in testing 713, i also notice the 303 sent back to the end user. this
>> is much different than what's seen with 621. at least with 621 a 5xx
>> reponse is sent  after all configured retries have been exhausted.
>>
>> that said.. whats the current status of this plugin? deprecated? no
>> longer supported ?
>>
>> is it safe to say, ATS core read_while_writer timers(and related
>> parameters) should be the preferred protections against thundering
>> herd ?
>> maybe at one time, core parameters were not sufficient to protect the
>> origin, which is why the plugin was developed in the first place.
>> but now core has caught up, and the plugin is no longer needed ?
>>
>> thanks!
>>
>>
>>
>>
>> On Wed, May 16, 2018 at 2:51 PM, Zelkowitz, Evan
>> <[email protected]> wrote:
>> > So now that Im testing it more I can see on the origin side that for each
>> > one of these ERR_CONNECT_FAILS that that is going back to my client
>> > application which is then getting the redirect and going to the origin.  It
>> > doesn’t even appear to be doing the number of retries or delays that I set
>> > for the collapsed_forwarding plugin.  So something seems to be going wrong
>> > with the plugin somewhere. I can see it attempting the delay, so it can see
>> > the writefail header, and it sets the ‘internal’ redirect properly but that
>> > appears to leak out back to the client before it gets attempted by ATS
>> > itself.
>> >
>> >
>> >
>> > From: "Zelkowitz, Evan" <[email protected]>
>> > Reply-To: "[email protected]" <[email protected]>
>> > Date: Tuesday, May 15, 2018 at 2:08 PM
>> > To: "[email protected]" <[email protected]>
>> > Subject: [EXTERNAL] Issue with collapsed forwarding plugin, one CONN_FAIL
>> >
>> >
>> >
>> > Ive been testing the collapsed forwarding plugin here by sending it random
>> > traffic, one request with 10 duplicates of the same request.  One thing Im
>> > seeing is that a lot of the time one of the requests out of those 10 will
>> > come back as an ERR_CONN_FAIL, but the pssc will be the 303 redirect.
>> >
>> >
>> >
>> > I was just wondering if this was expected? Is it an issue or has anyone 
>> > seen
>> > this?
>> >
>> >
>> >
>> > Here is my output logging showing one of these instances:
>> >
>> >
>> >
>> > 1526413868.121 chi=test-ip phn=test-cache-09.net php=80
>> > shn=origin-test-cache-52.net
>> > url=http://origin-test-cache-52.net/muxed-3000-prDi.tJZFQeIkXN_QYeLWwqAeRbJpH.ts
>> > cqhm=GET cqhv=HTTP/1.1 pssc=200 ttms=1 b=107782 sssc=200 sscl=107782
>> > cfsc=FIN pfsc=FIN crc=TCP_MISS phr=DIRECT pqsn=origin-test-cache-52.net
>> > uas="CUSTOMUAS/0.0.0" xmt="-"
>> >
>> > 1526413868.123 chi=test-ip phn=test-cache-09.net php=80
>> > shn=origin-test-cache-52.net
>> > url=http://origin-test-cache-52.net/muxed-3000-prDi.tJZFQeIkXN_QYeLWwqAeRbJpH.ts
>> > cqhm=GET cqhv=HTTP/1.1 pssc=200 ttms=0 b=107782 sssc=000 sscl=0 cfsc=FIN
>> > pfsc=FIN crc=TCP_HIT phr=NONE pqsn=- uas="CUSTOMUAS/0.0.0" xmt="-"
>> >
>> > 1526413868.124 chi=test-ip phn=test-cache-09.net php=80
>> > shn=origin-test-cache-52.net
>> > url=http://origin-test-cache-52.net/muxed-3000-prDi.tJZFQeIkXN_QYeLWwqAeRbJpH.ts
>> > cqhm=GET cqhv=HTTP/1.1 pssc=200 ttms=0 b=107782 sssc=000 sscl=0 cfsc=FIN
>> > pfsc=FIN crc=TCP_MEM_HIT phr=NONE pqsn=- uas="CUSTOMUAS/0.0.0" xmt="-"
>> >
>> > 1526413868.125 chi=test-ip phn=test-cache-09.net php=80
>> > shn=origin-test-cache-52.net
>> > url=http://origin-test-cache-52.net/muxed-3000-prDi.tJZFQeIkXN_QYeLWwqAeRbJpH.ts
>> > cqhm=GET cqhv=HTTP/1.1 pssc=200 ttms=0 b=107782 sssc=000 sscl=0 cfsc=FIN
>> > pfsc=FIN crc=TCP_MEM_HIT phr=NONE pqsn=- uas="CUSTOMUAS/0.0.0" xmt="-"
>> >
>> > 1526413868.126 chi=test-ip phn=test-cache-09.net php=80
>> > shn=origin-test-cache-52.net
>> > url=http://origin-test-cache-52.net/muxed-3000-prDi.tJZFQeIkXN_QYeLWwqAeRbJpH.ts
>> > cqhm=GET cqhv=HTTP/1.1 pssc=200 ttms=0 b=107782 sssc=000 sscl=0 cfsc=FIN
>> > pfsc=FIN crc=TCP_MEM_HIT phr=NONE pqsn=- uas="CUSTOMUAS/0.0.0" xmt="-"
>> >
>> > 1526413868.126 chi=test-ip phn=test-cache-09.net php=80
>> > shn=origin-test-cache-52.net
>> > url=http://origin-test-cache-52.net/muxed-3000-prDi.tJZFQeIkXN_QYeLWwqAeRbJpH.ts
>> > cqhm=GET cqhv=HTTP/1.1 pssc=200 ttms=0 b=107782 sssc=000 sscl=0 cfsc=FIN
>> > pfsc=FIN crc=TCP_MEM_HIT phr=NONE pqsn=- uas="CUSTOMUAS/0.0.0" xmt="-"
>> >
>> > 1526413868.127 chi=test-ip phn=test-cache-09.net php=80
>> > shn=origin-test-cache-52.net
>> > url=http://origin-test-cache-52.net/muxed-3000-prDi.tJZFQeIkXN_QYeLWwqAeRbJpH.ts
>> > cqhm=GET cqhv=HTTP/1.1 pssc=200 ttms=0 b=107782 sssc=000 sscl=0 cfsc=FIN
>> > pfsc=FIN crc=TCP_HIT phr=NONE pqsn=- uas="CUSTOMUAS/0.0.0" xmt="-"
>> >
>> > 1526413868.127 chi=test-ip phn=test-cache-09.net php=80
>> > shn=origin-test-cache-52.net
>> > url=http://origin-test-cache-52.net/muxed-3000-prDi.tJZFQeIkXN_QYeLWwqAeRbJpH.ts
>> > cqhm=GET cqhv=HTTP/1.1 pssc=200 ttms=60 b=107782 sssc=000 sscl=0 cfsc=FIN
>> > pfsc=FIN crc=TCP_MEM_HIT phr=NONE pqsn=- uas="CUSTOMUAS/0.0.0" xmt="-"
>> >
>> > 1526413868.121 chi=test-ip phn=test-cache-09.net php=80
>> > shn=origin-test-cache-52.net
>> > url=http://origin-test-cache-52.net/muxed-3000-prDi.tJZFQeIkXN_QYeLWwqAeRbJpH.ts
>> > cqhm=GET cqhv=HTTP/1.1 pssc=303 ttms=68 b=247 sssc=000 sscl=0 cfsc=FIN
>> > pfsc=FIN crc=ERR_CONNECT_FAIL phr=DIRECT pqsn=origin-test-cache-52.net
>> > uas="CUSTOMUAS/0.0.0" xmt="-"
>> >
>> > 1526413868.122 chi=test-ip phn=test-cache-09.net php=80
>> > shn=origin-test-cache-52.net
>> > url=http://origin-test-cache-52.net/muxed-3000-prDi.tJZFQeIkXN_QYeLWwqAeRbJpH.ts
>> > cqhm=GET cqhv=HTTP/1.1 pssc=200 ttms=108 b=107782 sssc=000 sscl=0 cfsc=FIN
>> > pfsc=FIN crc=TCP_MEM_HIT phr=NONE pqsn=- uas="CUSTOMUAS/0.0.0" xmt="-"
>> >
>> >
>> >
>> >
>>

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