On Tue, Feb 15, 2011 at 10:47 AM, Bert Huijben <b...@qqmail.nl> wrote: > > >> -----Original Message----- >> From: Hyrum K Wright [mailto:hy...@hyrumwright.org] >> Sent: dinsdag 15 februari 2011 11:44 >> To: Greg Stein >> Cc: C. Michael Pilato; Ivan Zhakov; dev@subversion.apache.org >> Subject: Re: [Proposal] Remove DAV properties cache in ra_serf >> >> On Tue, Feb 15, 2011 at 6:42 AM, Greg Stein <gst...@gmail.com> wrote: >> > On Mon, Feb 14, 2011 at 14:14, C. Michael Pilato <cmpil...@collab.net> >> wrote: >> >> On 02/14/2011 01:57 PM, Ivan Zhakov wrote: >> >>> Hi, >> >>> >> >>> Currently ra_serf caches *all* DAV properties retrieved using PROPFIND >> >>> in session pool. This was attempt to reduce number of PROPFIND >> >>> requests. But current implementation has several problems: >> >>> 1. Unlimited memory usage: current implementation stores all >> >>> properties, so svn ls -R command can easily eat 150 mb of memory. >> >>> 2. Very low cache hit due the fact that cache doesn't support caching >> >>> "allprop" requests. For some operations there is no hits at all. >> >>> 3. Current implementation caches properties that may change between >> >>> requests, like URL to youngest revision. >> >>> >> >>> Of course these problems can be fixed, but I'm not sure that we need >> >>> this code. Since in svn 1.7 we have HTTPv2 which doesn't use so many >> >>> PROPFIND requests that we tried to reduce using DAV properties cache. >> >>> >> >>> So I'm propose just to remove DAV properties cache from ra_serf. >> >>> Objections? Comments? >> >>> >> >>> PS: See attached patch in case you'd like test performance. >> >> >> >> Ivan, >> >> >> >> Thanks so much for looking so closely into ra_serf recently! It hadn't >> >> occurred to me when implementing the HTTPv2 stuff that the prop cache >> might >> >> become less useful as a result. >> >> >> >> But what is the effect for older servers? Would it make sense keep the >> >> cache logic, but conditionally use it only for non-HTTPv2 connections? >> > >> > Note that removing the cache will not *break* the code. It simply >> > makes operation a bit slower. >> > >> > "upgrade your server" >> > >> > Given that we can simplify the client (remove caching), and given that >> > we can avoid unbounded memory usage, and that we don't really need the >> > cache... it seems like a win. >> >> How far can we go with this? If we're not using cached DAV properties >> with ra_serf, and ra_serf is the default in 1.7, does it make sense to >> remove support for them from the 1.7 working copy? It shouldn't be >> too difficult, and would tighten libsvn_wc up a bit. > > This is about a different set of dav properties. > The working copy doesn't cache the HEAD revision for us or 'svn update' > would always be instantaneous ;-)
Ah, yes. Thanks for the clarification. (We overload the work properties much too much.) -Hyrum
