Hyrum K Wright wrote on Thu, Jul 07, 2011 at 08:29:31 -0500: > On Thu, Jul 7, 2011 at 2:36 AM, Philip Martin > <philip.mar...@wandisco.com> wrote: > > > > r0 revprops are a concern, they can have different access patterns. For > > example a master/slave setup running svnsync once per revision (a common > > setup) will write the r0 pack file several times per revision. We don't > > want the pack file to become the dominant IO. > > > > I wonder if we could offset the shard boundaries, so that r0 is the last > > revision in the first shard and r1-rN is the second shard. Then r0 > > would be a shard on its own and the r0 pack file would be much smaller. > > We would have to repack the repository on upgrade but the code changes > > for this could be small, just +/-1 in a few places. > > Changing the offsets for all the shard boundaries is just asking for > trouble, as it would mean that revision shards and revprop shards > wouldn't match up. That seems like a pretty big "gotcha". > > Instead, we could just special-case r0 revprops so that they never get > packed, and that the 0th shard includes r1:rN, instead of r0:rN. That > would only impact the 0th shard, rather than every revprop shard. >
+1
