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 >
