[
https://issues.apache.org/jira/browse/SOLR-127?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=12567068#action_12567068
]
Walter Underwood commented on SOLR-127:
---------------------------------------
Two reasons to do HTTP caching for Solr: First, Solr is HTTP and needs to
implement that correctly. Second, caches are much harder to implement and test
than the cache information in HTTP. HTTP caches already exist and are well
tested, so the implementation cost is zero and deployment is very easy.
The HTTP spec already covers which responses should be cached. A 400 response
may only be cached if it includes explicit cache control headers which allow
that. See RFC 2616.
We are using a caching load balancer and caching in Apache front ends to
Tomcat. We see an increase of more than 2X in the capacity of our search farm.
I would recommend against Solr-specific cache information in the XML part of
the responses. Distributed caching is extremely difficult to get right. Around
25% of the HTTP 1.1 spec is devoted to caching and there are still grey areas.
> Make Solr more friendly to external HTTP caches
> -----------------------------------------------
>
> Key: SOLR-127
> URL: https://issues.apache.org/jira/browse/SOLR-127
> Project: Solr
> Issue Type: Wish
> Reporter: Hoss Man
> Assignee: Hoss Man
> Fix For: 1.3
>
> Attachments: CacheUnitTest.patch, CacheUnitTest.patch,
> HTTPCaching.patch, HTTPCaching.patch, HTTPCaching.patch, HTTPCaching.patch,
> HTTPCaching.patch, HTTPCaching.patch, HTTPCaching.patch, HTTPCaching.patch,
> HTTPCaching.patch, HTTPCaching.patch, HTTPCaching.patch, HTTPCaching.patch,
> HTTPCaching.patch, HTTPCaching.patch, HTTPCaching.patch, HTTPCaching.patch,
> HTTPCaching.patch, HTTPCaching.patch, HTTPCaching.patch, HTTPCaching.patch,
> HTTPCaching.patch, HTTPCaching.patch, HTTPCaching.patch
>
>
> an offhand comment I saw recently reminded me of something that really bugged
> me about the serach solution i used *before* Solr -- it didn't play nicely
> with HTTP caches that might be sitting in front of it.
> at the moment, Solr doesn't put in particularly usefull info in the HTTP
> Response headers to aid in caching (ie: Last-Modified), responds to all HEAD
> requests with a 400, and doesn't do anything special with If-Modified-Since.
> t the very least, we can set a Last-Modified based on when the current
> IndexReder was open (if not the Date on the IndexReader) and use the same
> info to determing how to respond to If-Modified-Since requests.
> (for the record, i think the reason this hasn't occured to me in the 2+ years
> i've been using Solr, is because with the internal caching, i've yet to need
> to put a proxy cache in front of Solr)
--
This message is automatically generated by JIRA.
-
You can reply to this email to add a comment to the issue online.
