unwrap() essentially is doing a cast. If it returns null for unwrap(DrillTranslatableTable.class) or unwrap(DrillTable.class), it means the table associate with this TableScan does not implement either interface. My suspicion is JDBC storage plugin returns JdbcTable [1], unlikely other storage plugin which returns an instance implementing DrillTable.
This seems to indicate FindHardDistributionScans could not be used to non-DrillTable. I'm not sure if that's the intention of that code, though. 1. https://github.com/apache/calcite/blob/master/core/src/main/java/org/apache/calcite/adapter/jdbc/JdbcSchema.java#L233-L234 On Mon, Jun 19, 2017 at 2:19 PM, Muhammad Gelbana <[email protected]> wrote: > Everyone, > > I made a copy of the Jdbc plugin and made modifications to it by adding a > few rules. None of the modification I made or the rules I wrote should have > anything extra to do with handling the following SQL query > > SELECT * FROM incorta.SALES.SALES SALES WHERE 1 = 2 LIMIT 1 > > > I know the query is useless, but I need to to know how to fix the following > error thrown while handling this query. This is the final query plan: > > DEBUG o.a.d.e.p.s.h.DefaultSqlHandler - HEP_BOTTOM_UP:Convert SUM to $SUM0 > > (0ms): > > DrillLimitRel(*fetch=[1]*): rowcount = 1.0, cumulative cost = {201.0 > > rows, 205.0 cpu, 0.0 io, 0.0 network, 0.0 memory}, id = 2653 > > DrillLimitRel(*offset=[0], fetch=[0]*): rowcount = 1.0, cumulative cost > > = {200.0 rows, 201.0 cpu, 0.0 io, 0.0 network, 0.0 memory}, id = 2651 > > GelbanaJdbcDrel: rowcount = 100.0, cumulative cost = {200.0 rows, > > 201.0 cpu, 0.0 io, 0.0 network, 0.0 memory}, id = 2649 > > JdbcTableScan(table=[[gelbana, SALES, SALES]]): rowcount = 100.0, > > cumulative cost = {100.0 rows, 101.0 cpu, 0.0 io, 0.0 network, 0.0 > memory}, > > id = 2572 > > > This is the throw error stacktrace > > [Error Id: 83ea094a-db24-4d6d-bf0d-271db26db933 on 640fb7ebbd1a:31010] > at > org.apache.drill.common.exceptions.UserException$ > Builder.build(UserException.java:543) > ~[drill-common-1.9.0.jar:1.9.0] > at > org.apache.drill.exec.work.foreman.Foreman$ForemanResult. > close(Foreman.java:825) > [drill-java-exec-1.9.0.jar:1.9.0] > at org.apache.drill.exec.work.foreman.Foreman.moveToState( > Foreman.java:935) > [drill-java-exec-1.9.0.jar:1.9.0] > at org.apache.drill.exec.work.foreman.Foreman.run(Foreman.java:281) > [drill-java-exec-1.9.0.jar:1.9.0] > at > java.util.concurrent.ThreadPoolExecutor.runWorker( > ThreadPoolExecutor.java:1142) > [na:1.8.0_131] > at > java.util.concurrent.ThreadPoolExecutor$Worker.run( > ThreadPoolExecutor.java:617) > [na:1.8.0_131] > at java.lang.Thread.run(Thread.java:748) [na:1.8.0_131] > Caused by: org.apache.drill.exec.work.foreman.ForemanException: Unexpected > exception during fragment initialization: null > ... 4 common frames omitted > *Caused by: java.lang.NullPointerException: null* > at > org.apache.drill.exec.planner.sql.handlers.FindHardDistributionScans. > visit(FindHardDistributionScans.java:55) > ~[drill-java-exec-1.9.0.jar:1.9.0] > at org.apache.calcite.rel.core.TableScan.accept(TableScan.java:166) > ~[calcite-core-1.4.0-drill-r19.jar:1.4.0-drill-r19] > at org.apache.calcite.rel.RelShuttleImpl.visitChild( > RelShuttleImpl.java:53) > ~[calcite-core-1.4.0-drill-r19.jar:1.4.0-drill-r19] > at > org.apache.calcite.rel.RelShuttleImpl.visitChildren( > RelShuttleImpl.java:68) > ~[calcite-core-1.4.0-drill-r19.jar:1.4.0-drill-r19] > at org.apache.calcite.rel.RelShuttleImpl.visit(RelShuttleImpl.java:126) > ~[calcite-core-1.4.0-drill-r19.jar:1.4.0-drill-r19] > at org.apache.calcite.rel.AbstractRelNode.accept(AbstractRelNode.java:256) > ~[calcite-core-1.4.0-drill-r19.jar:1.4.0-drill-r19] > at org.apache.calcite.rel.RelShuttleImpl.visitChild( > RelShuttleImpl.java:53) > ~[calcite-core-1.4.0-drill-r19.jar:1.4.0-drill-r19] > at > org.apache.calcite.rel.RelShuttleImpl.visitChildren( > RelShuttleImpl.java:68) > ~[calcite-core-1.4.0-drill-r19.jar:1.4.0-drill-r19] > at org.apache.calcite.rel.RelShuttleImpl.visit(RelShuttleImpl.java:126) > ~[calcite-core-1.4.0-drill-r19.jar:1.4.0-drill-r19] > at org.apache.calcite.rel.AbstractRelNode.accept(AbstractRelNode.java:256) > ~[calcite-core-1.4.0-drill-r19.jar:1.4.0-drill-r19] > at org.apache.calcite.rel.RelShuttleImpl.visitChild( > RelShuttleImpl.java:53) > ~[calcite-core-1.4.0-drill-r19.jar:1.4.0-drill-r19] > at > org.apache.calcite.rel.RelShuttleImpl.visitChildren( > RelShuttleImpl.java:68) > ~[calcite-core-1.4.0-drill-r19.jar:1.4.0-drill-r19] > at org.apache.calcite.rel.RelShuttleImpl.visit(RelShuttleImpl.java:126) > ~[calcite-core-1.4.0-drill-r19.jar:1.4.0-drill-r19] > at org.apache.calcite.rel.AbstractRelNode.accept(AbstractRelNode.java:256) > ~[calcite-core-1.4.0-drill-r19.jar:1.4.0-drill-r19] > at > org.apache.drill.exec.planner.sql.handlers.FindHardDistributionScans. > canForceSingleMode(FindHardDistributionScans.java:45) > ~[drill-java-exec-1.9.0.jar:1.9.0] > at > org.apache.drill.exec.planner.sql.handlers.DefaultSqlHandler. > convertToDrel(DefaultSqlHandler.java:262) > ~[drill-java-exec-1.9.0.jar:1.9.0] > at > org.apache.drill.exec.planner.sql.handlers.DefaultSqlHandler. > convertToDrel(DefaultSqlHandler.java:290) > ~[drill-java-exec-1.9.0.jar:1.9.0] > at > org.apache.drill.exec.planner.sql.handlers.DefaultSqlHandler.getPlan( > DefaultSqlHandler.java:168) > ~[drill-java-exec-1.9.0.jar:1.9.0] > at > org.apache.drill.exec.planner.sql.DrillSqlWorker.getPhysicalPlan( > DrillSqlWorker.java:123) > ~[drill-java-exec-1.9.0.jar:1.9.0] > at > org.apache.drill.exec.planner.sql.DrillSqlWorker.getPlan( > DrillSqlWorker.java:97) > ~[drill-java-exec-1.9.0.jar:1.9.0] > at org.apache.drill.exec.work.foreman.Foreman.runSQL(Foreman.java:1008) > [drill-java-exec-1.9.0.jar:1.9.0] > at org.apache.drill.exec.work.foreman.Foreman.run(Foreman.java:264) > [drill-java-exec-1.9.0.jar:1.9.0] > ... 3 common frames omitted > > Whic is because this statement > > unwrap = > > scan.getTable().unwrap(DrillTranslatableTable.class).getDrillTable(); > > > In *FindHardDistributionScans.java:55* evaluates > *scan.getTable().unwrap(DrillTranslatableTable.class)* to null > > Would someone please explain to me what is Drill trying to do and what did > I do wrong ? > > *---------------------* > *Muhammad Gelbana* > http://www.linkedin.com/in/mgelbana >
