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https://issues.apache.org/jira/browse/DRILL-5359?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=15929452#comment-15929452
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ASF GitHub Bot commented on DRILL-5359:
---------------------------------------
Github user amansinha100 commented on the issue:
https://github.com/apache/drill/pull/786
+1
> ClassCastException when push down filter on the output of flatten into
> parquet scan
> -----------------------------------------------------------------------------------
>
> Key: DRILL-5359
> URL: https://issues.apache.org/jira/browse/DRILL-5359
> Project: Apache Drill
> Issue Type: Bug
> Components: Query Planning & Optimization
> Affects Versions: 1.9.0
> Reporter: Jinfeng Ni
> Assignee: Jinfeng Ni
> Fix For: 1.11.0
>
>
> The following simplified query would hit ClassCastException.
> {code}
> select n_regionkey
> from (select n_regionkey,
> flatten(nation.cities) as cities
> from cp.`tpch/nation.parquet` nation) as flattenedCities
> where flattenedCities.cities.`zip` = '12345';
> {code}
> Here is the stacktrace for the Exception :
> {code}
> caused by: java.lang.ClassCastException:
> org.apache.drill.common.expression.FunctionCall cannot be cast to
> org.apache.drill.common.expression.SchemaPath
> at
> org.apache.drill.exec.planner.logical.DrillOptiq$RexToDrill.visitCall(DrillOptiq.java:170)
> ~[classes/:na]
> at
> org.apache.drill.exec.planner.logical.DrillOptiq$RexToDrill.visitCall(DrillOptiq.java:80)
> ~[classes/:na]
> at org.apache.calcite.rex.RexCall.accept(RexCall.java:107)
> ~[calcite-core-1.4.0-drill-r19.jar:1.4.0-drill-r19]
> at
> org.apache.drill.exec.planner.logical.DrillOptiq$RexToDrill.doFunction(DrillOptiq.java:205)
> ~[classes/:na]
> at
> org.apache.drill.exec.planner.logical.DrillOptiq$RexToDrill.visitCall(DrillOptiq.java:105)
> ~[classes/:na]
> at
> org.apache.drill.exec.planner.logical.DrillOptiq$RexToDrill.visitCall(DrillOptiq.java:80)
> ~[classes/:na]
> at org.apache.calcite.rex.RexCall.accept(RexCall.java:107)
> ~[calcite-core-1.4.0-drill-r19.jar:1.4.0-drill-r19]
> at
> org.apache.drill.exec.planner.logical.DrillOptiq.toDrill(DrillOptiq.java:77)
> ~[classes/:na]
> at
> org.apache.drill.exec.store.parquet.ParquetPushDownFilter.doOnMatch(ParquetPushDownFilter.java:141)
> ~[classes/:na]
> at
> org.apache.drill.exec.store.parquet.ParquetPushDownFilter$1.onMatch(ParquetPushDownFilter.java:68)
> ~[classes/:na]
> {code}
> The cause of this problem: Parquet filter pushdown rule tries to push a
> filter expression containing item/flatten operators into parquet scan.
> However, the method DrillOptiq.toDrill() does not allow such expression
> (since "flatten" is not a scalar function).
> The solution is to disable pushing such filter expression. Even the rule
> allows, the underneath parquet metadata would not have the corresponding
> statistics; there is no point to considering push such filter expression.
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