Hi Leif and all, Just fyi, We have an enhanced version of the plugin, that we use internally that works around these limitations and is able to serve the stale copy to successive requests until a fresher copy is available.
We may work on open sourcing that version soon, if time permits. Thanks, Sudheer > On Oct 9, 2014, at 8:45 PM, "Sudheer Vinukonda" <sudhe...@yahoo-inc.com> > wrote: > > > >> On Oct 9, 2014, at 8:39 PM, "Leif Hedstrom" <zw...@apache.org> wrote: >> >> >>> On Oct 9, 2014, at 6:08 PM, Shu Kit Chan <chanshu...@gmail.com> wrote: >>> >>> It seems to be similar to this jira ticket - >>> https://issues.apache.org/jira/browse/TS-1463 >> >> Yeah, Kit is spot on. This is a known problem with the plugin, and it’s an >> artifact of how the ATS cache works. To be able to implement >> stale-while-revalidate, we’d need to make changes in the cache such that it >> does not update the dir entries etc. until the “new” version is available to >> be served. Alan? >> >> — leif >> >>> >>> Kit >>> >>>> On Thu, Oct 9, 2014 at 3:53 PM, Jared Ocker <oc...@ohsu.edu> wrote: >>>> >>>> We have the stale-while-revalidate plugin in place and have noticed some >>>> behavior that seems suboptimal. While cache is fresh, everything works >>>> great. The first page hit after our 300sec s-maxage has passed comes back >>>> with “Warning: 110 Response is stale” as expected. However, it appears to >>>> be deleting the cached file and then looking at the origin server to pull >>>> fresh content. Our origin servers aren’t exactly fast (hence the need for >>>> ATS), so this results in about 4 sec of time while that cache file doesn’t >>>> exist and any hits to that page need to wait for the content from the >>>> origin server. >>>> >>>> Additional information: >>>> s-maxage=300 >>>> stale-while-revalidate=604800 >>>> stale-if-error=31536000 >>>> >>>> When Age < s-maxage: >>>> >>>> * Via: ApacheTrafficServer/4.2.0 [cHs f] >>>> >>>> First page load after Age > s-maxage: >>>> >>>> * Via: ApacheTrafficServer/4.2.0 [cHs f] >>>> * Warning: 110 Response is stale >>>> >>>> At this point, Cache Inspector shows the cached file to be missing for 3-4 >>>> seconds >>>> >>>> Subsequent page loads during revalidation process: >>>> >>>> * Via: ApacheTrafficServer/4.2.0 [cMs Sf] >>>> * This page load also shows a cookie being loaded that only comes from >>>> our origin servers >>>> >>>> After the 3-4 second revalidation process, everything seems to go back to >>>> normal. >>>> >>>> I might just be missing something but this doesn’t appear to be working as >>>> designed. Does anyone know how I can get it to continue showing stale >>>> cache during the entire revalidation process? >>>> >>>> Thanks, >>>> .: Jared >>
