https://www.youtube.com/watch?v=kG6vzsk8T7E This presentation contains lots of details for query execution plan.
On Mon, May 4, 2015 at 7:10 AM, Carol McDonald <[email protected]> wrote: > https://cwiki.apache.org/confluence/display/DRILL/EXPLAIN+Commands > > On Mon, May 4, 2015 at 3:46 AM, George Lu <[email protected]> wrote: > > > Dear all, > > > > I have deployed Drill on several nodes in the cluster and experienced the > > query. > > I have some questions: > > > > 1) Can anyone show me some links to read for the Drill execution plan, > how > > to understand it. > > > > 2) I execute some group by query on HBase several times, some time very > > fast, while sometimes very slow, and even get exception, like "Query > > failed: RemoteRpcException: Failure while running fragment., Command > failed > > while establishing connection. Failure type CONNECTION. [ > > 2ba2092f-53ed-480a-9f23-f89b6e6a91a0 on test6:31010 ] > > [ 2ba2092f-53ed-480a-9f23-f89b6e6a91a0 on test6:31010 ] > > > > > > java.lang.RuntimeException: java.sql.SQLException: Failure while > executing > > query. > > at sqlline.SqlLine$IncrementalRows.hasNext(SqlLine.java:2514) > > at sqlline.SqlLine$TableOutputFormat.print(SqlLine.java:2148) > > at sqlline.SqlLine.print(SqlLine.java:1809) > > at sqlline.SqlLine$Commands.execute(SqlLine.java:3766) > > at sqlline.SqlLine$Commands.sql(SqlLine.java:3663) > > at sqlline.SqlLine.dispatch(SqlLine.java:889) > > at sqlline.SqlLine.begin(SqlLine.java:763) > > at sqlline.SqlLine.start(SqlLine.java:498) > > at sqlline.SqlLine.main(SqlLine.java:460)" > > > > I am not sure whether Drill uses pre-execute like in Hadoop or auto > failure > > detection. If some of the execution node failed, what will happen? If > some > > node is under high pressure for other task, and what will happen if this > > node becomes the one who drags the whole execution slow? > > > > Thanks! > > > > George > > >
