diff --git a/server/src/main/java/io/druid/segment/indexing/DataSchema.java b/server/src/main/java/io/druid/segment/indexing/DataSchema.java
index 3013c9728f7..b9f54e49c52 100644
--- a/server/src/main/java/io/druid/segment/indexing/DataSchema.java
+++ b/server/src/main/java/io/druid/segment/indexing/DataSchema.java
@@ -22,7 +22,9 @@ package io.druid.segment.indexing;
 import com.fasterxml.jackson.annotation.JsonCreator;
 import com.fasterxml.jackson.annotation.JsonProperty;
 import com.google.common.collect.Sets;
+import io.druid.data.input.impl.DimensionsSpec;
 import io.druid.data.input.impl.InputRowParser;
+import io.druid.data.input.impl.TimestampSpec;
 import io.druid.query.aggregation.AggregatorFactory;
 import io.druid.segment.indexing.granularity.GranularitySpec;
 import io.druid.segment.indexing.granularity.UniformGranularitySpec;
@@ -50,19 +52,28 @@ public class DataSchema
 
     final Set<String> dimensionExclusions = Sets.newHashSet();
     for (AggregatorFactory aggregator : aggregators) {
-      dimensionExclusions.add(aggregator.getName());
+      dimensionExclusions.addAll(aggregator.requiredFields());
     }
     if (parser != null && parser.getParseSpec() != null) {
-      if (parser.getParseSpec().getTimestampSpec() != null) {
-        dimensionExclusions.add(parser.getParseSpec().getTimestampSpec().getTimestampColumn());
+      final DimensionsSpec dimensionsSpec = parser.getParseSpec().getDimensionsSpec();
+      final TimestampSpec timestampSpec = parser.getParseSpec().getTimestampSpec();
+
+      // exclude timestamp from dimensions by default, unless explicitly included in the list of dimensions
+      if (timestampSpec != null) {
+        final String timestampColumn = timestampSpec.getTimestampColumn();
+        if (!(dimensionsSpec.hasCustomDimensions() && dimensionsSpec.getDimensions().contains(timestampColumn))) {
+          dimensionExclusions.add(timestampColumn);
+        }
       }
-      if (parser.getParseSpec().getDimensionsSpec() != null) {
+      if (dimensionsSpec != null) {
         this.parser = parser.withParseSpec(
             parser.getParseSpec()
                   .withDimensionsSpec(
-                      parser.getParseSpec()
-                            .getDimensionsSpec()
-                            .withDimensionExclusions(dimensionExclusions)
+                      dimensionsSpec
+                            .withDimensionExclusions(
+                                Sets.difference(dimensionExclusions,
+                                                Sets.newHashSet(dimensionsSpec.getDimensions()))
+                            )
                   )
         );
       } else {
diff --git a/server/src/test/java/io/druid/segment/indexing/DataSchemaTest.java b/server/src/test/java/io/druid/segment/indexing/DataSchemaTest.java
new file mode 100644
index 00000000000..99ecdc43780
--- /dev/null
+++ b/server/src/test/java/io/druid/segment/indexing/DataSchemaTest.java
@@ -0,0 +1,87 @@
+/*
+ * Druid - a distributed column store.
+ * Copyright (C) 2014  Metamarkets Group Inc.
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License
+ * as published by the Free Software Foundation; either version 2
+ * of the License, or (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301, USA.
+ */
+
+package io.druid.segment.indexing;
+
+import com.google.common.collect.ImmutableList;
+import com.google.common.collect.ImmutableSet;
+import io.druid.data.input.impl.DimensionsSpec;
+import io.druid.data.input.impl.JSONParseSpec;
+import io.druid.data.input.impl.StringInputRowParser;
+import io.druid.data.input.impl.TimestampSpec;
+import io.druid.granularity.QueryGranularity;
+import io.druid.query.aggregation.AggregatorFactory;
+import io.druid.query.aggregation.DoubleSumAggregatorFactory;
+import io.druid.segment.indexing.granularity.ArbitraryGranularitySpec;
+import org.junit.Assert;
+import org.joda.time.Interval;
+import org.junit.Test;
+
+public class DataSchemaTest
+{
+  @Test
+  public void testDefaultExclusions() throws Exception
+  {
+    DataSchema schema = new DataSchema(
+        "test",
+        new StringInputRowParser(
+            new JSONParseSpec(
+                new TimestampSpec("time", "auto"),
+                new DimensionsSpec(ImmutableList.of("dimB", "dimA"), null, null)
+            ),
+            null, null, null, null
+        ),
+        new AggregatorFactory[]{
+            new DoubleSumAggregatorFactory("metric1", "col1"),
+            new DoubleSumAggregatorFactory("metric2", "col2"),
+        },
+        new ArbitraryGranularitySpec(QueryGranularity.DAY, ImmutableList.of(Interval.parse("2014/2015")))
+    );
+
+    Assert.assertEquals(
+        ImmutableSet.of("time", "col1", "col2"),
+        schema.getParser().getParseSpec().getDimensionsSpec().getDimensionExclusions()
+    );
+  }
+
+  @Test
+  public void testExplicitInclude() throws Exception
+  {
+    DataSchema schema = new DataSchema(
+        "test",
+        new StringInputRowParser(
+            new JSONParseSpec(
+                new TimestampSpec("time", "auto"),
+                new DimensionsSpec(ImmutableList.of("time", "dimA", "dimB", "col2"), ImmutableList.of("dimC"), null)
+            ),
+            null, null, null, null
+        ),
+        new AggregatorFactory[]{
+            new DoubleSumAggregatorFactory("metric1", "col1"),
+            new DoubleSumAggregatorFactory("metric2", "col2"),
+        },
+        new ArbitraryGranularitySpec(QueryGranularity.DAY, ImmutableList.of(Interval.parse("2014/2015")))
+    );
+
+    Assert.assertEquals(
+        ImmutableSet.of("dimC", "col1"),
+        schema.getParser().getParseSpec().getDimensionsSpec().getDimensionExclusions()
+    );
+  }
+}