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http://issues.apache.org/bugzilla/show_bug.cgi?id=35211 Summary: RFE: Better support for Vary Headers in mod_cache Product: Apache httpd-2.0 Version: 2.1-HEAD Platform: All OS/Version: All Status: NEW Severity: enhancement Priority: P4 Component: mod_cache AssignedTo: [email protected] ReportedBy: [EMAIL PROTECTED] CC: [EMAIL PROTECTED] Currently, mod_cache is RFC compliant in its handling of Vary headers, but it behaves in a less than optimal manner. If a reply contains the vary header, it is noted. If the varied headers match in both the stored version and the client request, the cache is used. If the varied headers are missing or do not match, the cached copy is not used. When the cached copy is not used, a new version is fetched from the backend, and replaces the previously cached copy, that contained different values for the Varied headers. This effectively kills the cache hit rate when using the Vary header, since anytime a header does vary the cached copy is destroyed. The enhancement would be storing one copy of the page, for every Varied header value/combination. One possible solution is to include the Varied headers in the Cache Hash. This would give each combination of varied headers, values and URLs their own unique hash, and would enable the current mod_disk_cache and mod_mem_cache to operate with little or no changes. The problem is that we do not know if a URL should be varied, until after we have already determined the Cache Hash. If this route is taken, some method to change the cache hash at a later time might be needed. Another possible solution, that would require changes to both mod_mem_cache, mod_disk_cache, and htcacheclean, would be to make some knid of 'index' node. This node would contain a list of all known combinations for each varied header, and the location of the cached version of each. -- Configure bugmail: http://issues.apache.org/bugzilla/userprefs.cgi?tab=email ------- You are receiving this mail because: ------- You are the assignee for the bug, or are watching the assignee. --------------------------------------------------------------------- To unsubscribe, e-mail: [EMAIL PROTECTED] For additional commands, e-mail: [EMAIL PROTECTED]
