Github user JoshRosen commented on a diff in the pull request:
https://github.com/apache/spark/pull/5725#discussion_r29268634
--- Diff:
sql/catalyst/src/main/java/org/apache/spark/sql/catalyst/expressions/UnsafeRow.java
---
@@ -0,0 +1,428 @@
+/*
+ * Licensed to the Apache Software Foundation (ASF) under one or more
+ * contributor license agreements. See the NOTICE file distributed with
+ * this work for additional information regarding copyright ownership.
+ * The ASF licenses this file to You under the Apache License, Version 2.0
+ * (the "License"); you may not use this file except in compliance with
+ * the License. You may obtain a copy of the License at
+ *
+ * http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package org.apache.spark.sql.catalyst.expressions;
+
+import scala.collection.Map;
+import scala.collection.Seq;
+import scala.collection.mutable.ArraySeq;
+
+import javax.annotation.Nullable;
+import java.math.BigDecimal;
+import java.sql.Date;
+import java.util.*;
+
+import org.apache.spark.sql.Row;
+import org.apache.spark.sql.types.DataType;
+import static org.apache.spark.sql.types.DataTypes.*;
+import org.apache.spark.sql.types.StructType;
+import org.apache.spark.sql.types.UTF8String;
+import org.apache.spark.unsafe.PlatformDependent;
+import org.apache.spark.unsafe.bitset.BitSetMethods;
+
+/**
+ * An Unsafe implementation of Row which is backed by raw memory instead
of Java objects.
+ *
+ * Each tuple has three parts: [null bit set] [values] [variable length
portion]
+ *
+ * The bit set is used for null tracking and is aligned to 8-byte word
boundaries. It stores
+ * one bit per field.
+ *
+ * In the `values` region, we store one 8-byte word per field. For fields
that hold fixed-length
+ * primitive types, such as long, double, or int, we store the value
directly in the word. For
+ * fields with non-primitive or variable-length values, we store a
relative offset (w.r.t. the
+ * base address of the row) that points to the beginning of the
variable-length field.
+ *
+ * Instances of `UnsafeRow` act as pointers to row data stored in this
format, similar to how
+ * `Writable` objects work in Hadoop.
+ */
+public final class UnsafeRow implements MutableRow {
+
+ private Object baseObject;
+ private long baseOffset;
+ /** The number of fields in this row, used for calculating the bitset
width (and in assertions) */
+ private int numFields;
+ /** The width of the null tracking bit set, in bytes */
+ private int bitSetWidthInBytes;
+ /**
+ * This optional schema is required if you want to call generic get()
and set() methods on
+ * this UnsafeRow, but is optional if callers will only use
type-specific getTYPE() and setTYPE()
+ * methods.
+ */
+ @Nullable
+ private StructType schema;
+
+ private long getFieldOffset(int ordinal) {
+ return baseOffset + bitSetWidthInBytes + ordinal * 8L;
+ }
+
+ public static int calculateBitSetWidthInBytes(int numFields) {
+ return ((numFields / 64) + (numFields % 64 == 0 ? 0 : 1)) * 8;
+ }
+
+ /**
+ * Field types that can be updated in place in UnsafeRows (e.g. we
support set() for these types)
+ */
+ public static final Set<DataType> settableFieldTypes;
+
+ /**
+ * Fields types can be read(but not set (e.g. set() will throw
UnsupportedOperationException).
+ */
+ public static final Set<DataType> readableFieldTypes;
+
+ static {
+ settableFieldTypes = Collections.unmodifiableSet(
+ new HashSet<DataType>(
+ Arrays.asList(new DataType[] {
--- End diff --
Done: https://issues.apache.org/jira/browse/SPARK-7199
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