> In general dynamic pages should be cachable. There are two cases known to
> me where that is false.
>
> a) page is dynamic, without cache-control info and meant to be non-cachable.
>
> This is the reason we add the 0 0% 0 refresh pattern to replace the old
> QUERY acl. It means consider all indeterminate dynamic requests as
> non-cacheble. Just to be safe.
>
> b) the page is one of the above but has been passed to a peer by squid.
>
> This is our fault, squid adds an otherwise unnoticeable cache-control
> header to requests passed in peering. This breaks the refresh_pattern
> safety check for (a).
>
> None yet has coded the patch for (b). So dynamic caching works in squid,
> but not on requests received from peers.
Aha, thanks for the info. I added this ACL to curb ICP requests:
acl swf urlpath_regex clown_widget.swf
icp_access deny swf
And now there are corresponding UDP_DENIED msgs:
22/Aug/2008:01:40:24 -0700.049 0 110.0.2.78 UDP_DENIED/000 88
ICP_QUERY http://contentreal.foobar.com/clown_widget.swf?version=20080820
- NONE/- -
But requests still occasionally timeout:
[root_at_mongo ~]# wget -S
http://content5.foobar.com/clown_widget.swf?version=20080820
--03:38:07-- http://content5.foobar.com/clown_widget.swf?version=20080820
=> `clown_widget.swf?version=20080820'
HTTP request sent, awaiting response...
HTTP/1.0 200 OK
Last-Modified: Fri, 08 Aug 2008 06:07:10 GMT
Accept-Ranges: bytes
Content-Length: 219919
Content-Type: application/x-shockwave-flash
Date: Fri, 22 Aug 2008 12:28:44 GMT
Server: Apache
ETag: "35b0f"
Expires: Sat, 23 Aug 2008 12:28:44 GMT
Cache-Control: max-age=86400
X-Cache: HIT from squid04.foobar.com
X-Cache-Lookup: HIT from squid04.foobar.com:80
Age: 567
X-Cache: HIT from squid01.foobar.com
X-Cache-Lookup: HIT from squid01.foobar.com:80
Via: 1.1 squid04.foobar.com:80 (squid), 1.0 squid01.foobar.com:80 (squid)
Connection: keep-alive
Length: 219,919 (215K) [application/x-shockwave-flash]
16% [=====> ] 35,664 --.--K/s ETA 00:20
22/Aug/2008:05:33:31 -0700.843 279168 65.0.22.251 TCP_MISS/200 161676
GET http://contentreal.foobar.com/clown_widget.swf?version=20080820 -
CD_SIBLING_HIT/110.0.2.78 application/x-shockwave-flash
Looks like digest hits are still wreaking havoc? Anyone know of any
workarounds aside from removing sibling/parent relationships?
Received on Fri Aug 22 2008 - 13:24:13 MDT
This archive was generated by hypermail 2.2.0 : Fri Aug 22 2008 - 12:00:03 MDT