Hi Paul, certainly makes sense to have the API compatibility discussions during this hackathon. The 2.0 release may be a good checkpoint to introduce breaking changes necessitating changes to the ODBC/JDBC drivers and other external applications. As part of this exercise (not during the hackathon but as a follow-up action), we also should clearly identify the "public" interfaces.
I will add this to the agenda. thanks, -Aman On Tue, Aug 29, 2017 at 2:08 PM, Paul Rogers <prog...@mapr.com> wrote: > Thanks Aman for organizing the Hackathon! > > The list included many good ideas for Drill 2.0. Some of those require > changes to Drill’s “public” interfaces (file format, client protocol, SQL > behavior, etc.) > > At present, Drill has no good mechanism to handle backward/forward > compatibility at the API level. Protobuf versioning certainly helps, but > can’t completely solve semantic changes (where a field changes meaning, or > a non-Protobuf data chunk changes format.) As just one concrete example, > changing to Arrow will break pre-Arrow ODBC/JDBC drivers because class > names and data formats will change. > > Perhaps we can prioritize, for the proposed 2.0 release, a one-time set of > breaking changes that introduce a versioning mechanism into our public > APIs. Once these are in place, we can evolve the APIs in the future by > following the newly-created versioning protocol. > > Without such a mechanism, we cannot support old & new clients in the same > cluster. Nor can we support rolling upgrades. Of course, another solution > is to get it right the second time, then freeze all APIs and agree to never > again change them. Not sure we have sufficient access to a crystal ball to > predict everything we’d ever need in our APIs, however... > > Thanks, > > - Paul > > > On Aug 24, 2017, at 8:39 AM, Aman Sinha <amansi...@apache.org> wrote: > > > > Drill Developers, > > > > In order to kick-start the Drill 2.0 release discussions, I would like > to > > propose a Drill 2.0 (design) hackathon (a.k.a Drill Developer Day ™ J ). > > > > As I mentioned in the hangout on Tuesday, MapR has offered to host it on > > Sept 18th at their offices at 350 Holger Way, San Jose. Hope that works > > for most of you! > > > > The goal is to get the community together for a day-long technical > > discussion on key topics in preparation for a Drill 2.0 release as well > as > > potential improvements in upcoming 1.xx releases. Depending on the > > interest areas, we could form groups and have a volunteer lead each > group. > > > > Based on prior discussions on the dev list, hangouts and existing JIRAs, > > there is already a substantial set of topics and I have summarized a few > of > > them below. What other topics do folks want to talk about? Feel free > to > > respond to this thread and I will create a google doc to consolidate. > > Understandably, the list would be long but we will use the hackathon to > get > > a sense of a reasonable feature set for 1.xx and 2.0 releases. > > > > > > 1. Metadata management. > > > > 1a: Defining an abstraction layer for various types of metadata: views, > > schema, statistics, security > > > > 1b: Underlying storage for metadata: what are the options and their > > trade-offs? > > > > - Hive metastore > > > > - Parquet metadata cache (parquet specific) > > > > - An embedded DBMS > > > > - A distributed key-value store > > > > - Others.. > > > > > > > > 2. Drill integration with Apache Arrow > > > > 2a: Evaluate the choices and tradeoffs > > > > > > > > 3. Resource management > > > > 3a: Memory limits per query > > > > 3b: Spilling > > > > 3c: Resource management with Drill on Yarn/Mesos/Kubernetes > > > > 3d: Local vs. global resource management > > > > 3e: Aligning with admission control/queueing > > > > > > > > 4. TPC-DS coverage and related planner/operator enhancements > > > > 4a: Additional set operations: INTERSECT, EXCEPT > > > > 4b: GROUPING SETS, ROLLUP, CUBE support > > > > 4c: Handling inequality joins and cartesian joins of non-scalar inputs > > (via Nested Loop Join) > > > > 4d: Remaining gaps in correlated subquery > > > > 4e: Statistics: Number of Distinct Values, Histograms > > > > > > > > 5. Schema handling > > > > 5a: Creation, management of schema > > > > 5b: Handling schema changes in certain common cases > > > > 5c: Schema-awareness > > > > 5d: Others TBD > > > > > > > > 6. Concurrency > > > > 6a: What are the bottlenecks to achieving higher concurrency > > > > 6b: Ideas to address these..e.g async execution ? > > > > > > > > 7. Storage plugins, REST APIs related enhancements > > > > <Topics TBD> > > > > > > > > 8. Performance improvements > > > > 8a: Filter pushdown > > > > 8b: Vectorized Parquet reader > > > > 8c: Code-gen improvements > > > > 8d: Others TBD > >
