Hi everyone, As an update, the core HLC work has been pushed out as an initial commit to a public branch called HBASE-14070.HLC <https://git-wip-us.apache.org/repos/asf?p=hbase.git;a=shortlog;h=refs/heads/HBASE-14070.HLC>. Details regarding the core HLC commit can be viewed at HBASE-18305 <https://issues.apache.org/jira/browse/HBASE-18305>. The next step will be another commit on that branch that would undo using the master's timestamp for meta updates. The progress for this task will be tracked in HBASE-18328 <https://issues.apache.org/jira/browse/HBASE-18328>.
On Fri, Jun 23, 2017 at 10:38 AM, Enis Söztutar <enis....@gmail.com> wrote: > The plan looks good. > > >However, if it is done before HBase 2.0.0 beta and if it is proven to be > solid, then we can discuss bringing it back to 2.0.0. > It will be pretty good to have at least the base in 2.0, so that we can > later enable HLC for user tables in later releases. Of course, it depends > sufficient testing. > > Enis > > On Fri, Jun 23, 2017 at 10:03 AM, Amit Patel <amit.pa...@cloudera.com> > wrote: > > > For now, yes, that is the plan. However, if it is done before HBase 2.0.0 > > beta and if it is proven to be solid, then we can discuss bringing it > back > > to 2.0.0. > > > > On Fri, Jun 23, 2017 at 6:12 AM, Sean Busbey <bus...@apache.org> wrote: > > > > > It'd be great to see this land. You only mention the master branch as > > > a merge target; is the assumption that this would only be a HBase 3.0+ > > > addition? > > > > > > On Thu, Jun 22, 2017 at 7:34 PM, Amit Patel <amit.pa...@cloudera.com> > > > wrote: > > > > Hi everyone, > > > > > > > > > > > > > > > > I'm Amit and I've been picking up on the past work on Hybrid Logical > > > Clocks > > > > (HBASE-14070 <https://issues.apache.org/jira/browse/HBASE-14070>) > that > > > was > > > > done by Sai Teja Ranuva last summer. The most recent status of HLC on > > > HBase > > > > can be found here > > > > <https://docs.google.com/document/d/1n32DUKoL3LSoKQ1_ > > > NuF8TbQkZiZCwFhbHZ7JXRjg3oA/edit#> > > > > and a prior document by Enis Soztutar with discussion can be found > here > > > > <https://docs.google.com/document/d/1LL2GAodiYi0waBz5ODGL4LDT4e_ > > > bXy8P9h6kWC05Bhw/edit#>. > > > > I think the effort is at a point where it makes sense to create a > > public > > > > branch. > > > > > > > > > > > > > > > > Currently the plan is to create a public branch and incrementally add > > on > > > > functionality and tests. Initially, core HLC would be introduced as a > > > > commit. From there, HLC would then be enabled for just the meta table > > > > (updating the clock on events like region open/close, recovery, > > > > replication, etc). Once we are fully confident that HLC at least > works > > on > > > > the meta table then I anticipate it would be appropriate to merge > with > > > the > > > > master branch. > > > > > > > > > > > > > > > > Follow up commits would extend the effort by: > > > > > > > > > > > > > > > > - > > > > > > > > Addition of a protobuf message called NodeTime that holds > timestamp > > > > corresponding to a send event between nodes. > > > > - > > > > > > > > Addition of NodeTime as a field to messages sent between nodes for > > > > messages like requests and responses for region open/close. > > > > - > > > > > > > > Addition of integration tests that verify HLC works correctly with > > > > recovery, replication, region open, and region close. > > > > - > > > > > > > > Later enabling HLC on user tables (main barrier are tests that > rely > > on > > > > client-side setting of timestamps for table mutations which would > no > > > longer > > > > be allowed on an HLC table). > > > > > > > > > > > > > > > > Work that I have implemented under the outstanding work > > > > <https://docs.google.com/document/d/1n32DUKoL3LSoKQ1_ > > > NuF8TbQkZiZCwFhbHZ7JXRjg3oA/edit#heading=h.8x5d8iakmo8b> > > > > as a part of getting HLC working for user tables includes: > > > > > > > > > > > > > > > > - > > > > > > > > Mapping of time ranges from client GETs > > > > - > > > > > > > > Disallowing clients to set timestamps for HLC and System Monotonic > > > tables > > > > > > > > > > > > > > > > Feel free to chime in with any comments, suggestions, or other input. > > > > > > > > -- > > > > Amit > > > > > > > > > > > -- > > Amit > > > -- Amit
