On Sat, Mar 3, 2012 at 5:31 AM, <stef...@apache.org> wrote: > Author: stefan2 > Date: Sat Mar 3 11:31:17 2012 > New Revision: 1296604 > > URL: http://svn.apache.org/viewvc?rev=1296604&view=rev > Log: > Certain operations, e.g. svn ls, will contain timestamp and author > information from many different revisions. A list of all projects > in the root of the wordpress repository will open, read and close >>75.000 revision property files (3 reads for each list entry) > > This commit implements revprop caching. It will be activated as > part of the full-text caching option. > > Since revprops may be written by other threads or processes, we > need to track the revprop changes. A new special file contains a > counter that will be increased each time revision properties get > rewritten. > > This counter is internally called "revprop generation" and will be > read upon the first revprop access for given fs_t. Later changes > may remain invisible for that fs_t. This behavior is in line with > our revprop handling in other parts of FS_FS. If a revprop gets > rewritten, the fs_t doing the write will use the new generation > from that point on and will thus see all caches up to and including > its own. > > Since the revprop generation becomes part of the cache key, each > fs_t will only see revprops from its generation. It may also > create new cache entries tagged with that generation, i.e. those > would appear to be outdated for newer fs_t. But that will simply > cause a benign false negative upon lookup. No fs_t will see > data that got replaced before that fs_t was created.
How does this potentially interact with revprop packing? -Hyrum -- uberSVN: Apache Subversion Made Easy http://www.uberSVN.com/
