Null checking is on by default. You can disable it by setting either the system property or the + * environmental variable to "false". The system property is named "arrow.enable_null_check_for_get" and + * the environmental variable is named "ARROW_ENABLE_NULL_CHECK_FOR_GET". + * When both the system property and the environmental variable are set, the system property takes precedence. + *
+ *+ * Disabling null-checking in the "get" methods may lead to performance improvements. + * For example, suppose we have the following micro-benchmark: + *
+ *+ *
{@code
+ *
+ * Float8Vector vector = ...
+ *
+ * public void test() {
+ * sum = 0;
+ * for (int i = 0; i < 1024; i++) {
+ * vector.set(i, i + 10.0);
+ * safeSum += vector.get(i);
+ * }
+ * }
+ *
+ * }
+ *
+ * + * Performance evaluations of the micro-benchmark with the JMH framework reveal that, disabling null checking + * has the following effects: + * 1. The amounts of byte code and assembly code generated by JIT are both smaller. + * 2. The performance improves by about 30% (2.819 ± 0.005 us/op vs. 4.069 ± 0.004 us/op). + *
+ *+ * Therefore, for scenarios where the user can be sure that the null-checking is unnecessary, + * it is beneficial to disable it with this configuration. + *
+ */ +public class NullCheckingForGet { + + /** + * The flag to indicate if null checking is enabled for "get" methods. + */ + public static final boolean NULL_CHECKING_ENABLED; + + static { + String envProperty = System.getenv("ARROW_ENABLE_NULL_CHECK_FOR_GET"); + String sysProperty = System.getProperty("arrow.enable_null_check_for_get"); + + // The system property has a higher priority than the environmental variable. + String flagValue = sysProperty; + if (flagValue == null) { + flagValue = envProperty; + } + + // The flag is set to false only if the system property/environmental + // variable is explicitly set to "false". + NULL_CHECKING_ENABLED = !"false".equals(flagValue); + } + + private NullCheckingForGet() { + } +} diff --git a/java/vector/src/main/java/org/apache/arrow/vector/SmallIntVector.java b/java/vector/src/main/java/org/apache/arrow/vector/SmallIntVector.java index 8e9eb4476a4..dddc46fef2b 100644 --- a/java/vector/src/main/java/org/apache/arrow/vector/SmallIntVector.java +++ b/java/vector/src/main/java/org/apache/arrow/vector/SmallIntVector.java @@ -17,6 +17,8 @@ package org.apache.arrow.vector; +import static org.apache.arrow.vector.NullCheckingForGet.NULL_CHECKING_ENABLED; + import org.apache.arrow.memory.BufferAllocator; import org.apache.arrow.vector.complex.impl.SmallIntReaderImpl; import org.apache.arrow.vector.complex.reader.FieldReader; @@ -97,7 +99,7 @@ public MinorType getMinorType() { * @return element at given index */ public short get(int index) throws IllegalStateException { - if (isSet(index) == 0) { + if (NULL_CHECKING_ENABLED && isSet(index) == 0) { throw new IllegalStateException("Value at index is null"); } return valueBuffer.getShort(index * TYPE_WIDTH); diff --git a/java/vector/src/main/java/org/apache/arrow/vector/TimeMicroVector.java b/java/vector/src/main/java/org/apache/arrow/vector/TimeMicroVector.java index 6d9b4fc8b23..a8cb0fe5bfb 100644 --- a/java/vector/src/main/java/org/apache/arrow/vector/TimeMicroVector.java +++ b/java/vector/src/main/java/org/apache/arrow/vector/TimeMicroVector.java @@ -17,6 +17,8 @@ package org.apache.arrow.vector; +import static org.apache.arrow.vector.NullCheckingForGet.NULL_CHECKING_ENABLED; + import org.apache.arrow.memory.BufferAllocator; import org.apache.arrow.vector.complex.impl.TimeMicroReaderImpl; import org.apache.arrow.vector.complex.reader.FieldReader; @@ -97,7 +99,7 @@ public MinorType getMinorType() { * @return element at given index */ public long get(int index) throws IllegalStateException { - if (isSet(index) == 0) { + if (NULL_CHECKING_ENABLED && isSet(index) == 0) { throw new IllegalStateException("Value at index is null"); } return valueBuffer.getLong(index * TYPE_WIDTH); diff --git a/java/vector/src/main/java/org/apache/arrow/vector/TimeMilliVector.java b/java/vector/src/main/java/org/apache/arrow/vector/TimeMilliVector.java index d7aa9273791..adf7562c116 100644 --- a/java/vector/src/main/java/org/apache/arrow/vector/TimeMilliVector.java +++ b/java/vector/src/main/java/org/apache/arrow/vector/TimeMilliVector.java @@ -17,6 +17,8 @@ package org.apache.arrow.vector; +import static org.apache.arrow.vector.NullCheckingForGet.NULL_CHECKING_ENABLED; + import java.time.LocalDateTime; import org.apache.arrow.memory.BufferAllocator; @@ -99,7 +101,7 @@ public MinorType getMinorType() { * @return element at given index */ public int get(int index) throws IllegalStateException { - if (isSet(index) == 0) { + if (NULL_CHECKING_ENABLED && isSet(index) == 0) { throw new IllegalStateException("Value at index is null"); } return valueBuffer.getInt(index * TYPE_WIDTH); diff --git a/java/vector/src/main/java/org/apache/arrow/vector/TimeNanoVector.java b/java/vector/src/main/java/org/apache/arrow/vector/TimeNanoVector.java index 50e7d8e0e8b..2a288191b45 100644 --- a/java/vector/src/main/java/org/apache/arrow/vector/TimeNanoVector.java +++ b/java/vector/src/main/java/org/apache/arrow/vector/TimeNanoVector.java @@ -17,6 +17,8 @@ package org.apache.arrow.vector; +import static org.apache.arrow.vector.NullCheckingForGet.NULL_CHECKING_ENABLED; + import org.apache.arrow.memory.BufferAllocator; import org.apache.arrow.vector.complex.impl.TimeNanoReaderImpl; import org.apache.arrow.vector.complex.reader.FieldReader; @@ -97,7 +99,7 @@ public MinorType getMinorType() { * @return element at given index */ public long get(int index) throws IllegalStateException { - if (isSet(index) == 0) { + if (NULL_CHECKING_ENABLED && isSet(index) == 0) { throw new IllegalStateException("Value at index is null"); } return valueBuffer.getLong(index * TYPE_WIDTH); diff --git a/java/vector/src/main/java/org/apache/arrow/vector/TimeSecVector.java b/java/vector/src/main/java/org/apache/arrow/vector/TimeSecVector.java index df444e48979..5198a26ca23 100644 --- a/java/vector/src/main/java/org/apache/arrow/vector/TimeSecVector.java +++ b/java/vector/src/main/java/org/apache/arrow/vector/TimeSecVector.java @@ -17,6 +17,8 @@ package org.apache.arrow.vector; +import static org.apache.arrow.vector.NullCheckingForGet.NULL_CHECKING_ENABLED; + import org.apache.arrow.memory.BufferAllocator; import org.apache.arrow.vector.complex.impl.TimeSecReaderImpl; import org.apache.arrow.vector.complex.reader.FieldReader; @@ -97,7 +99,7 @@ public MinorType getMinorType() { * @return element at given index */ public int get(int index) throws IllegalStateException { - if (isSet(index) == 0) { + if (NULL_CHECKING_ENABLED && isSet(index) == 0) { throw new IllegalStateException("Value at index is null"); } return valueBuffer.getInt(index * TYPE_WIDTH); diff --git a/java/vector/src/main/java/org/apache/arrow/vector/TimeStampVector.java b/java/vector/src/main/java/org/apache/arrow/vector/TimeStampVector.java index a84a96266a0..5f66ddc3f0e 100644 --- a/java/vector/src/main/java/org/apache/arrow/vector/TimeStampVector.java +++ b/java/vector/src/main/java/org/apache/arrow/vector/TimeStampVector.java @@ -17,6 +17,8 @@ package org.apache.arrow.vector; +import static org.apache.arrow.vector.NullCheckingForGet.NULL_CHECKING_ENABLED; + import org.apache.arrow.memory.BufferAllocator; import org.apache.arrow.vector.types.pojo.FieldType; import org.apache.arrow.vector.util.TransferPair; @@ -57,7 +59,7 @@ public TimeStampVector(String name, FieldType fieldType, BufferAllocator allocat * @return element at given index */ public long get(int index) throws IllegalStateException { - if (isSet(index) == 0) { + if (NULL_CHECKING_ENABLED && isSet(index) == 0) { throw new IllegalStateException("Value at index is null"); } return valueBuffer.getLong(index * TYPE_WIDTH); diff --git a/java/vector/src/main/java/org/apache/arrow/vector/TinyIntVector.java b/java/vector/src/main/java/org/apache/arrow/vector/TinyIntVector.java index d5c0beff499..df40b6e57cc 100644 --- a/java/vector/src/main/java/org/apache/arrow/vector/TinyIntVector.java +++ b/java/vector/src/main/java/org/apache/arrow/vector/TinyIntVector.java @@ -17,6 +17,8 @@ package org.apache.arrow.vector; +import static org.apache.arrow.vector.NullCheckingForGet.NULL_CHECKING_ENABLED; + import org.apache.arrow.memory.BufferAllocator; import org.apache.arrow.vector.complex.impl.TinyIntReaderImpl; import org.apache.arrow.vector.complex.reader.FieldReader; @@ -97,7 +99,7 @@ public MinorType getMinorType() { * @return element at given index */ public byte get(int index) throws IllegalStateException { - if (isSet(index) == 0) { + if (NULL_CHECKING_ENABLED && isSet(index) == 0) { throw new IllegalStateException("Value at index is null"); } return valueBuffer.getByte(index * TYPE_WIDTH); diff --git a/java/vector/src/main/java/org/apache/arrow/vector/UInt1Vector.java b/java/vector/src/main/java/org/apache/arrow/vector/UInt1Vector.java index 8b19cdf8580..6064cb4dcce 100644 --- a/java/vector/src/main/java/org/apache/arrow/vector/UInt1Vector.java +++ b/java/vector/src/main/java/org/apache/arrow/vector/UInt1Vector.java @@ -17,6 +17,8 @@ package org.apache.arrow.vector; +import static org.apache.arrow.vector.NullCheckingForGet.NULL_CHECKING_ENABLED; + import org.apache.arrow.memory.BufferAllocator; import org.apache.arrow.vector.complex.impl.UInt1ReaderImpl; import org.apache.arrow.vector.complex.reader.FieldReader; @@ -69,7 +71,7 @@ public MinorType getMinorType() { * @return element at given index */ public byte get(int index) throws IllegalStateException { - if (isSet(index) == 0) { + if (NULL_CHECKING_ENABLED && isSet(index) == 0) { throw new IllegalStateException("Value at index is null"); } return valueBuffer.getByte(index * TYPE_WIDTH); diff --git a/java/vector/src/main/java/org/apache/arrow/vector/UInt2Vector.java b/java/vector/src/main/java/org/apache/arrow/vector/UInt2Vector.java index 5e1237e02e6..aab6969b086 100644 --- a/java/vector/src/main/java/org/apache/arrow/vector/UInt2Vector.java +++ b/java/vector/src/main/java/org/apache/arrow/vector/UInt2Vector.java @@ -17,6 +17,8 @@ package org.apache.arrow.vector; +import static org.apache.arrow.vector.NullCheckingForGet.NULL_CHECKING_ENABLED; + import org.apache.arrow.memory.BufferAllocator; import org.apache.arrow.vector.complex.impl.UInt2ReaderImpl; import org.apache.arrow.vector.complex.reader.FieldReader; @@ -69,7 +71,7 @@ public MinorType getMinorType() { * @return element at given index */ public char get(int index) throws IllegalStateException { - if (isSet(index) == 0) { + if (NULL_CHECKING_ENABLED && isSet(index) == 0) { throw new IllegalStateException("Value at index is null"); } return valueBuffer.getChar(index * TYPE_WIDTH); diff --git a/java/vector/src/main/java/org/apache/arrow/vector/UInt4Vector.java b/java/vector/src/main/java/org/apache/arrow/vector/UInt4Vector.java index edaef22ef3d..203c2691874 100644 --- a/java/vector/src/main/java/org/apache/arrow/vector/UInt4Vector.java +++ b/java/vector/src/main/java/org/apache/arrow/vector/UInt4Vector.java @@ -17,6 +17,8 @@ package org.apache.arrow.vector; +import static org.apache.arrow.vector.NullCheckingForGet.NULL_CHECKING_ENABLED; + import org.apache.arrow.memory.BufferAllocator; import org.apache.arrow.vector.complex.impl.UInt4ReaderImpl; import org.apache.arrow.vector.complex.reader.FieldReader; @@ -69,7 +71,7 @@ public MinorType getMinorType() { * @return element at given index */ public int get(int index) throws IllegalStateException { - if (isSet(index) == 0) { + if (NULL_CHECKING_ENABLED && isSet(index) == 0) { throw new IllegalStateException("Value at index is null"); } return valueBuffer.getInt(index * TYPE_WIDTH); diff --git a/java/vector/src/main/java/org/apache/arrow/vector/UInt8Vector.java b/java/vector/src/main/java/org/apache/arrow/vector/UInt8Vector.java index cab162b55c1..e404bc3579b 100644 --- a/java/vector/src/main/java/org/apache/arrow/vector/UInt8Vector.java +++ b/java/vector/src/main/java/org/apache/arrow/vector/UInt8Vector.java @@ -17,6 +17,8 @@ package org.apache.arrow.vector; +import static org.apache.arrow.vector.NullCheckingForGet.NULL_CHECKING_ENABLED; + import org.apache.arrow.memory.BufferAllocator; import org.apache.arrow.vector.complex.impl.UInt8ReaderImpl; import org.apache.arrow.vector.complex.reader.FieldReader; @@ -69,7 +71,7 @@ public MinorType getMinorType() { * @return element at given index */ public long get(int index) throws IllegalStateException { - if (isSet(index) == 0) { + if (NULL_CHECKING_ENABLED && isSet(index) == 0) { throw new IllegalStateException("Value at index is null"); } return valueBuffer.getLong(index * TYPE_WIDTH); diff --git a/java/vector/src/main/java/org/apache/arrow/vector/VarBinaryVector.java b/java/vector/src/main/java/org/apache/arrow/vector/VarBinaryVector.java index a0f4e7b0c1f..60483c0a79c 100644 --- a/java/vector/src/main/java/org/apache/arrow/vector/VarBinaryVector.java +++ b/java/vector/src/main/java/org/apache/arrow/vector/VarBinaryVector.java @@ -17,6 +17,8 @@ package org.apache.arrow.vector; +import static org.apache.arrow.vector.NullCheckingForGet.NULL_CHECKING_ENABLED; + import org.apache.arrow.memory.BufferAllocator; import org.apache.arrow.vector.complex.impl.VarBinaryReaderImpl; import org.apache.arrow.vector.complex.reader.FieldReader; @@ -95,7 +97,7 @@ public MinorType getMinorType() { */ public byte[] get(int index) { assert index >= 0; - if (isSet(index) == 0) { + if (NULL_CHECKING_ENABLED && isSet(index) == 0) { throw new IllegalStateException("Value at index is null"); } final int startOffset = getstartOffset(index); diff --git a/java/vector/src/main/java/org/apache/arrow/vector/VarCharVector.java b/java/vector/src/main/java/org/apache/arrow/vector/VarCharVector.java index a6a23eaf77f..b5cd253591a 100644 --- a/java/vector/src/main/java/org/apache/arrow/vector/VarCharVector.java +++ b/java/vector/src/main/java/org/apache/arrow/vector/VarCharVector.java @@ -17,6 +17,8 @@ package org.apache.arrow.vector; +import static org.apache.arrow.vector.NullCheckingForGet.NULL_CHECKING_ENABLED; + import org.apache.arrow.memory.BufferAllocator; import org.apache.arrow.vector.complex.impl.VarCharReaderImpl; import org.apache.arrow.vector.complex.reader.FieldReader; @@ -92,7 +94,7 @@ public MinorType getMinorType() { */ public byte[] get(int index) { assert index >= 0; - if (isSet(index) == 0) { + if (NULL_CHECKING_ENABLED && isSet(index) == 0) { throw new IllegalStateException("Value at index is null"); } final int startOffset = getstartOffset(index); diff --git a/java/vector/src/test/java/org/apache/arrow/vector/TestNullCheckingForGet.java b/java/vector/src/test/java/org/apache/arrow/vector/TestNullCheckingForGet.java new file mode 100644 index 00000000000..f1345e88ab8 --- /dev/null +++ b/java/vector/src/test/java/org/apache/arrow/vector/TestNullCheckingForGet.java @@ -0,0 +1,92 @@ +/* + * 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.arrow.vector; + +import java.lang.reflect.Field; +import java.net.URLClassLoader; + +import org.junit.Assert; +import org.junit.Test; + +/** + * Test cases for {@link NullCheckingForGet}. + */ +public class TestNullCheckingForGet { + + /** + * Get a copy of the current class loader. + * @return the newly created class loader. + */ + private ClassLoader copyClassLoader() { + ClassLoader curClassLoader = this.getClass().getClassLoader(); + if (curClassLoader instanceof URLClassLoader) { + // for Java 1.8 + return new URLClassLoader(((URLClassLoader) curClassLoader).getURLs(), null); + } + + // for Java 1.9 and Java 11. + return null; + } + + /** + * Get the value of flag {@link NullCheckingForGet#NULL_CHECKING_ENABLED}. + * @param classLoader the class loader from which to get the flag value. + * @return value of the flag. + */ + private boolean getFlagValue(ClassLoader classLoader) throws Exception { + Class clazz = classLoader.loadClass("org.apache.arrow.vector.NullCheckingForGet"); + Field field = clazz.getField("NULL_CHECKING_ENABLED"); + return (Boolean) field.get(null); + } + + /** + * Ensure the flag for null checking is enabled by default. + * This will protect users from JVM crashes. + */ + @Test + public void testDefaultValue() throws Exception { + ClassLoader classLoader = copyClassLoader(); + if (classLoader != null) { + boolean nullCheckingEnabled = getFlagValue(classLoader); + Assert.assertTrue(nullCheckingEnabled); + } + } + + /** + * Test setting the null checking flag by the system property. + * @throws Exception if loading class {@link NullCheckingForGet#NULL_CHECKING_ENABLED} fails. + */ + @Test + public void testEnableSysProperty() throws Exception { + String sysProperty = System.getProperty("arrow.enable_null_check_for_get"); + System.setProperty("arrow.enable_null_check_for_get", "false"); + + ClassLoader classLoader = copyClassLoader(); + if (classLoader != null) { + boolean nullCheckingEnabled = getFlagValue(classLoader); + Assert.assertFalse(nullCheckingEnabled); + } + + // restore system property + if (sysProperty != null) { + System.setProperty("arrow.enable_null_check_for_get", sysProperty); + } else { + System.clearProperty("arrow.enable_null_check_for_get"); + } + } +}