From e2c5bcc22d2c175bba51fbb2a9c90303ecdf6f44 Mon Sep 17 00:00:00 2001
From: Samarth Jain <samarth@apache.org>
Date: Wed, 1 Jul 2020 20:06:23 -0700
Subject: [PATCH] =?UTF-8?q?Fix=20UnknownComplexTypeColumn#makeVectorObject?=
 =?UTF-8?q?Selector.=20Add=20a=20warning=20=E2=80=A6=20(#10123)?=
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 8bit

* Fix UnknownComplexTypeColumn#makeVectorObjectSelector. Add a warning message to indicate failure in deserializing.
---
 .../column/UnknownTypeComplexColumn.java      | 19 +------------------
 .../segment/serde/ComplexColumnPartSerde.java |  7 +++++++
 2 files changed, 8 insertions(+), 18 deletions(-)

diff --git a/processing/src/main/java/org/apache/druid/segment/column/UnknownTypeComplexColumn.java b/processing/src/main/java/org/apache/druid/segment/column/UnknownTypeComplexColumn.java
index 7332a5c3822..ce4db70438e 100644
--- a/processing/src/main/java/org/apache/druid/segment/column/UnknownTypeComplexColumn.java
+++ b/processing/src/main/java/org/apache/druid/segment/column/UnknownTypeComplexColumn.java
@@ -25,7 +25,6 @@ import org.apache.druid.segment.data.ReadableOffset;
 import org.apache.druid.segment.vector.NilVectorSelector;
 import org.apache.druid.segment.vector.ReadableVectorOffset;
 import org.apache.druid.segment.vector.VectorObjectSelector;
-import org.apache.druid.segment.vector.VectorSizeInspector;
 
 import javax.annotation.Nullable;
 
@@ -38,22 +37,6 @@ public class UnknownTypeComplexColumn implements ComplexColumn
     return INSTANCE;
   }
 
-  private static final NilVectorSelector NIL_VECTOR_SELECTOR_INSTANCE =
-      NilVectorSelector.create(new VectorSizeInspector()
-      {
-        @Override
-        public int getMaxVectorSize()
-        {
-          return 0;
-        }
-
-        @Override
-        public int getCurrentVectorSize()
-        {
-          return 0;
-        }
-      });
-
   @Override
   public Class<?> getClazz()
   {
@@ -94,6 +77,6 @@ public class UnknownTypeComplexColumn implements ComplexColumn
   @Override
   public VectorObjectSelector makeVectorObjectSelector(ReadableVectorOffset offset)
   {
-    return NIL_VECTOR_SELECTOR_INSTANCE;
+    return NilVectorSelector.create(offset);
   }
 }
diff --git a/processing/src/main/java/org/apache/druid/segment/serde/ComplexColumnPartSerde.java b/processing/src/main/java/org/apache/druid/segment/serde/ComplexColumnPartSerde.java
index f10f53baf79..dc0278baaed 100644
--- a/processing/src/main/java/org/apache/druid/segment/serde/ComplexColumnPartSerde.java
+++ b/processing/src/main/java/org/apache/druid/segment/serde/ComplexColumnPartSerde.java
@@ -21,6 +21,7 @@ package org.apache.druid.segment.serde;
 
 import com.fasterxml.jackson.annotation.JsonCreator;
 import com.fasterxml.jackson.annotation.JsonProperty;
+import org.apache.druid.java.util.common.logger.Logger;
 import org.apache.druid.segment.GenericColumnSerializer;
 
 import javax.annotation.Nullable;
@@ -33,11 +34,17 @@ public class ComplexColumnPartSerde implements ColumnPartSerde
   @Nullable
   private final ComplexMetricSerde serde;
   private final Serializer serializer;
+  private static final Logger log = new Logger(ComplexColumnPartSerde.class);
 
   private ComplexColumnPartSerde(String typeName, Serializer serializer)
   {
     this.typeName = typeName;
     this.serde = ComplexMetrics.getSerdeForType(typeName);
+    if (this.serde == null) {
+      // Not choosing to fail here since this gets handled as
+      // an UnknownTypeComplexColumn. See SimpleColumnHolder#getColumn.
+      log.warn("Unknown complex column of type %s detected", typeName);
+    }
     this.serializer = serializer;
   }