On 08/10/2012 06:20 AM, Justin Erenkrantz wrote: > FWIW, last week, I went down the path of trying to optimize the 'ls' > client path - which issues two OPTIONS requests...which is kinda > silly. but to remove it, requires that the RA open call also return > the youngest revision. I rev'd all of the RA layers, but then got > stuck in a maze of twisty calls inside libsvn_client to try and use > that revnum to skip the later call which invokes OPTIONS again...I > should probably post that incomplete patch before moving on to > something else. =)
If it makes you feel better, I've been down this road before, too. :-) One thing that occurs to me as possible solution is to add a flag to svn_ra_openX() which instructs the RA layer to immediately negotiate the current youngest rev and then freeze that snapshot of the repository for the duration of the RA session's lifetime. The client layer alone knows whether the high-level operation it is performing would be effected by additional commits to the repository. So for read-only operations, the clients would pass this flag to the RA open stuffs, and the RA layer would cache the youngest-rev. Future calls to svn_ra_get_latest_revnum() on that session would always return the cached value. Other RA calls that allow you to use SVN_INVALID_REVNUM to mean "HEAD" would also use the cached youngest-rev. Is that crazy? My one concern is that it might negatively effect code clarity. If I see svn_ra_get_latest_revnum(ra_session, &youngest, pool) in the client code, I can't immediately tell if that function call will get the *realtime* youngest revision or the frozen snapshot revision. I'd need to find the ra-open call to see if that special flag was provided. -- C-Mike PS: Going really nuts, we *could* allow the RA session to "peg" not merely the current HEAD, but any arbitrary revision as the youngest revision the RA session will be allowed to recognize. But I can't quickly come up with a good reason for doing that. -- C. Michael Pilato <cmpil...@collab.net> CollabNet <> www.collab.net <> Enterprise Cloud Development
signature.asc
Description: OpenPGP digital signature
