Trouble understanding Varnishlog

[Lucas Brasilino]

Hi

> Can someone explain why the object is not being returned as a cached object?

Because your client is performing a conditional request and so
revalidating using
If-None-Match/Etag headers the already cached object in your machine.

Your client is issuing:

>   15 RxHeader     c If-None-Match: "4ee85970d12afd8992d3dc1651f07b9d"

It means: please send me the object if none match with this Etag value.

Varnish responds:

>   15 TxStatus     c 304
>   15 TxResponse   c Not Modified
[...]
>   15 TxHeader     c ETag: "4ee85970d12afd8992d3dc1651f07b9d"

It means: the object you have is the same one I have.

Transfering an object you already have is a waste of resources :)

regards
Lucas Brasilino



> I'm confused around the fact that it says there is a 'hit', but the
> X-Varnish header only has 1 field.
> I read that if the Set-Cookie header is sent, then varnish does not cache
> the object, but I'm pretty sure thats not being sent. Is there another rule
> I'm missing? Thanks.
> Here is an excerpt of the log:
>   15 SessionOpen  c 10.0.19.23 59326 :80
>   15 ReqStart     c 10.0.19.23 59326 1001168302
>   15 RxRequest    c GET
>   15 RxURL        c /items?xzy=true
>   15 RxProtocol   c HTTP/1.1
>   15 RxHeader     c Host: XYZ
>   15 RxHeader     c User-Agent: Mozilla/5.0 (Macintosh; U; Intel Mac OS X
> 10.6; en-US; rv:1.9.2.13) Gecko/20101203 Firefox/3.6.13 GTB7.1
>   15 RxHeader     c Accept:
> text/html,application/xhtml+xml,application/xml;q=0.9,*/*;q=0.8
>   15 RxHeader     c Accept-Language: en-us,en;q=0.5
>   15 RxHeader     c Accept-Encoding: gzip,deflate
>   15 RxHeader     c Accept-Charset: ISO-8859-1,utf-8;q=0.7,*;q=0.7
>   15 RxHeader     c Keep-Alive: 115
>   15 RxHeader     c Connection: keep-alive
>   15 RxHeader     c Cookie: __qca=P0-707762352-1283409801091;
> __utma=182775871.333345873.1284063320.1293103561.1293171223.24;
> __utmz=182775871.1284063320.1.1.utmcsr=(direct)|utmccn=(direct)|utmcmd=(none);
> km_lv=x; km_ai=T7R0VpZshcfDBJiF4n8Edt1vrrI; km_uq=; __utmv=182775871.p
>   15 RxHeader     c If-None-Match: "4ee85970d12afd8992d3dc1651f07b9d"
>   15 VCL_call     c recv
>   15 VCL_return   c lookup
>   15 VCL_call     c hash
>   15 VCL_return   c hash
>   15 Hit          c 1001168004
>   15 VCL_call     c hit
>   15 VCL_return   c deliver
>   15 VCL_call     c deliver
>   15 VCL_return   c deliver
>   15 TxProtocol   c HTTP/1.1
>   15 TxStatus     c 304
>   15 TxResponse   c Not Modified
>   15 TxHeader     c Date: Tue, 28 Dec 2010 23:19:53 GMT
>   15 TxHeader     c Via: 1.1 varnish
>   15 TxHeader     c X-Varnish: 1001168302
>   15 TxHeader     c Cache-Control: private, max-age=0, must-revalidate
>   15 TxHeader     c ETag: "4ee85970d12afd8992d3dc1651f07b9d"
>   15 TxHeader     c Connection: keep-alive
>   15 Length       c 0
>   15 ReqEnd       c 1001168302 1293578393.040635109 1293578393.040782928
> 0.000112057 0.000097990 0.000049829
>   15 Debug        c "herding"
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