Not 0.19, 0.20. RPC compatibility is the key. Let 0.20.3 or 0.20.2 clients operate against HBase running on HDFS 0.21 (with durable WAL etc.) without any change to the client side.
- Andy ----- Original Message ---- > From: Ryan Rawson <ryano...@gmail.com> > To: hbase-u...@hadoop.apache.org > Cc: hbase-dev@hadoop.apache.org > Sent: Tue, January 26, 2010 11:34:26 AM > Subject: Re: new HBase 0.20 on Hadoop 0.21 branch > > If it is just API compat, why not re-add the 0.19 API to 0.21. It > hasn't even been a year since the new 0.20 API was released... > Maintaining the old API costs nothing in terms of core code (ie: its > not preventing us from doing features). > > -ryan > > On Mon, Jan 25, 2010 at 6:40 PM, Andrew Purtell wrote: > > I have opened a branch for 0.20 (currently 0.20.3 RC2) updated to run on > Hadoop 0.21 > > (currently 0.21-dev) It's passing all unit tests now. > > > > http://svn.apache.org/repos/asf/hadoop/hbase/branches/0.20_on_hadoop-0.21 > > > > The aim is for client API compatibility. This is an intermediate step for > upgrading > > to 0.21 so HDFS improvements, e.g. hflush and we hope also HDFS-630, can be > > incorporated immediately through an upgrade of the deployment but without > requiring > > any change to users of the HBase client API or the Thrift or Stargate > connectors. > > > > Unlike the 0.20 on Hadoop 0.18.3 branch, the 0.20 on 0.21 branch has a more > > aggressive strategy for back end changes -- things that touch HDFS and/or a > major > > performance win may go in, evaluated on a case by case basis, as long as > > they > do > > not change client side API or semantics. For example, the HLog and related > THBase > > improvements from HBase trunk have been backported. > > > > I do not expect to maintain this branch beyond some transition period, > > maybe > until > > 0.21.1. > > > > - Andy > > > > > > > > > >
