DRILL-6850: Allow configuring table names case sensitivity for JDBC storage plugin

closes #1542

1 files changed, 3 insertions, 0 deletions

diff --git a/exec/java-exec/src/main/java/org/apache/drill/exec/planner/sql/handlers/FindHardDistributionScans.java b/exec/java-exec/src/main/java/org/apache/drill/exec/planner/sql/handlers/FindHardDistributionScans.java
index 90cc178fe..7d87aa2c8 100644
--- a/exec/java-exec/src/main/java/org/apache/drill/exec/planner/sql/handlers/FindHardDistributionScans.java
+++ b/exec/java-exec/src/main/java/org/apache/drill/exec/planner/sql/handlers/FindHardDistributionScans.java
@@ -53,6 +53,9 @@ class FindHardDistributionScans extends RelShuttleImpl {
     unwrap = scan.getTable().unwrap(DrillTable.class);
     if (unwrap == null) {
       DrillTranslatableTable drillTranslatableTable = scan.getTable().unwrap(DrillTranslatableTable.class);
+      // For the case, when the underlying Table was obtained from Calcite,
+      // it extends neither DrillTable nor DrillTranslatableTable.
+      // Therefore DistributionAffinity type cannot be determined and single mode is rejected.
       if (drillTranslatableTable == null) {
         contains = true; // it rejects single mode.
         return scan;