nastra commented on a change in pull request #3966: URL: https://github.com/apache/iceberg/pull/3966#discussion_r798844481
########## File path: core/src/main/java/org/apache/iceberg/util/ZOrderByteUtils.java ########## @@ -0,0 +1,162 @@ +/* + * 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.iceberg.util; + +import java.nio.ByteBuffer; +import java.util.Arrays; + +/** + * Within Z-Ordering the byte representations of objects being compared must be ordered, + * this requires several types to be transformed when converted to bytes. The goal is to + * map object's whose byte representation are not lexicographically ordered into representations + * that are lexicographically ordered. + * Most of these techniques are derived from + * https://aws.amazon.com/blogs/database/z-order-indexing-for-multifaceted-queries-in-amazon-dynamodb-part-2/ + * + * Some implementation is taken from + * https://github.com/apache/hbase/blob/master/hbase-common/src/main/java/org/apache/hadoop/hbase/util/OrderedBytes.java + */ +public class ZOrderByteUtils { + + private ZOrderByteUtils() { + + } + + /** + * Signed ints do not have their bytes in magnitude order because of the sign bit. + * To fix this, flip the sign bit so that all negatives are ordered before positives. This essentially + * shifts the 0 value so that we don't break our ordering when we cross the new 0 value. + */ + public static byte[] intToOrderedBytes(int val) { + ByteBuffer bytes = ByteBuffer.allocate(Integer.BYTES); + bytes.putInt(val ^ 0x80000000); + return bytes.array(); + } + + /** + * Signed longs are treated the same as the signed ints + */ + public static byte[] longToOrderBytes(long val) { + ByteBuffer bytes = ByteBuffer.allocate(Long.BYTES); + bytes.putLong(val ^ 0x8000000000000000L); + return bytes.array(); + } + + /** + * Signed shorts are treated the same as the signed ints + */ + public static byte[] shortToOrderBytes(short val) { + ByteBuffer bytes = ByteBuffer.allocate(Short.BYTES); + bytes.putShort((short) (val ^ (0x8000))); + return bytes.array(); + } + + /** + * Signed tiny ints are treated the same as the signed ints + */ + public static byte[] tinyintToOrderedBytes(byte val) { + ByteBuffer bytes = ByteBuffer.allocate(Byte.BYTES); + bytes.put((byte) (val ^ (0x80))); + return bytes.array(); + } + + /** + * IEEE 754 : + * “If two floating-point numbers in the same format are ordered (say, x {@literal <} y), + * they are ordered the same way when their bits are reinterpreted as sign-magnitude integers.” + * + * Which means floats can be treated as sign magnitude integers which can then be converted into lexicographically + * comparable bytes + */ + public static byte[] floatToOrderedBytes(float val) { + ByteBuffer bytes = ByteBuffer.allocate(Integer.BYTES); + int ival = Float.floatToIntBits(val); + ival ^= ((ival >> (Integer.SIZE - 1)) | Integer.MIN_VALUE); + bytes.putInt(ival); + return bytes.array(); + } + + /** + * Doubles are treated the same as floats + */ + public static byte[] doubleToOrderedBytes(double val) { + ByteBuffer bytes = ByteBuffer.allocate(Long.BYTES); + long lng = Double.doubleToLongBits(val); + lng ^= ((lng >> (Long.SIZE - 1)) | Long.MIN_VALUE); + bytes.putLong(lng); + return bytes.array(); + } + + /** + * Strings are lexicographically sortable BUT if different byte array lengths will + * ruin the Z-Ordering. (ZOrder requires that a given column contribute the same number of bytes every time). + * This implementation just uses a set size to for all output byte representations. Truncating longer strings + * and right padding 0 for shorter strings. + */ + public static byte[] stringToOrderedBytes(String val, int length) { + ByteBuffer bytes = ByteBuffer.allocate(length); + if (val != null) { + int maxLength = Math.min(length, val.length()); + bytes.put(val.getBytes(), 0, maxLength); + } + return bytes.array(); + } + + /** + * Interleave bits using a naive loop. + * @param columnsBinary an array of byte arrays, none of which are empty Review comment: nit: is the `none of which are empty` commit still valid given that there are tests for empty arrays? ########## File path: core/src/test/java/org/apache/iceberg/util/TestZOrderByteUtil.java ########## @@ -0,0 +1,260 @@ +/* + * 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.iceberg.util; + +import java.util.Arrays; +import java.util.Random; +import org.apache.iceberg.relocated.com.google.common.primitives.UnsignedBytes; +import org.apache.iceberg.types.Types; +import org.junit.Assert; +import org.junit.Test; + +public class TestZOrderByteUtil { + private static final byte IIIIIIII = (byte) 255; + private static final byte IOIOIOIO = (byte) 170; + private static final byte OIOIOIOI = (byte) 85; + private static final byte OOOOIIII = (byte) 15; + private static final byte OOOOOOOI = (byte) 1; + private static final byte OOOOOOOO = (byte) 0; + + private static final int NUM_TESTS = 100000; + + private final Random random = new Random(42); + + private String bytesToString(byte[] bytes) { + StringBuilder result = new StringBuilder(); + for (byte b : bytes) { + result.append(String.format("%8s", Integer.toBinaryString(b & 0xFF)).replace(' ', '0')); + } + return result.toString(); + } + + /** + * Returns a non-0 length byte array + */ + private byte[] generateRandomBytes() { + int length = Math.abs(random.nextInt(100) + 1); + byte[] result = new byte[length]; + random.nextBytes(result); + return result; + } + + /** + * Test method to ensure correctness of byte interleaving code + */ + private String interleaveStrings(String[] strings) { + StringBuilder result = new StringBuilder(); + int totalLength = Arrays.stream(strings).mapToInt(String::length).sum(); + int substringIndex = 0; + int characterIndex = 0; + while (characterIndex < totalLength) { + for (String str : strings) { + if (substringIndex < str.length()) { + result.append(str.charAt(substringIndex)); + characterIndex++; + } + } + substringIndex++; + } + return result.toString(); + } + + /** + * Compares the result of a string based interleaving algorithm implemented above + * versus the binary bit-shifting algorithm used in ZOrderByteUtils. Either both + * algorithms are identically wrong or are both identically correct. + */ + @Test + public void testInterleaveRandomExamples() { + for (int test = 0; test < NUM_TESTS; test++) { + int numByteArrays = Math.abs(random.nextInt(6)) + 1; + byte[][] testBytes = new byte[numByteArrays][]; + String[] testStrings = new String[numByteArrays]; + for (int byteIndex = 0; byteIndex < numByteArrays; byteIndex++) { + testBytes[byteIndex] = generateRandomBytes(); + testStrings[byteIndex] = bytesToString(testBytes[byteIndex]); + } + byte[] byteResult = ZOrderByteUtils.interleaveBits(testBytes); + String byteResultAsString = bytesToString(byteResult); + + String stringResult = interleaveStrings(testStrings); + + Assert.assertEquals("String interleave didn't match byte interleave", stringResult, byteResultAsString); + } + } + + @Test + public void testInterleaveEmptyBits() { + byte[][] test = new byte[4][10]; + byte[] expected = new byte[40]; + + Assert.assertArrayEquals("Should combine empty arrays", + expected, ZOrderByteUtils.interleaveBits(test)); + } + + @Test + public void testInterleaveFullBits() { + byte[][] test = new byte[4][]; + test[0] = new byte[]{IIIIIIII, IIIIIIII}; + test[1] = new byte[]{IIIIIIII}; + test[2] = new byte[0]; + test[3] = new byte[]{IIIIIIII, IIIIIIII, IIIIIIII}; + byte[] expected = new byte[]{IIIIIIII, IIIIIIII, IIIIIIII, IIIIIIII, IIIIIIII, IIIIIIII}; + + Assert.assertArrayEquals("Should combine full arrays", + expected, ZOrderByteUtils.interleaveBits(test)); + } + + @Test + public void testInterleaveMixedBits() { + byte[][] test = new byte[4][]; + test[0] = new byte[]{OOOOOOOI, IIIIIIII, OOOOOOOO, OOOOIIII}; + test[1] = new byte[]{OOOOOOOI, OOOOOOOO, IIIIIIII}; + test[2] = new byte[]{OOOOOOOI}; + test[3] = new byte[]{OOOOOOOI}; + byte[] expected = new byte[]{ + OOOOOOOO, OOOOOOOO, OOOOOOOO, OOOOIIII, + IOIOIOIO, IOIOIOIO, + OIOIOIOI, OIOIOIOI, + OOOOIIII}; + Assert.assertArrayEquals("Should combine mixed byte arrays", + expected, ZOrderByteUtils.interleaveBits(test)); + } + + @Test + public void testIntOrdering() { + for (int i = 0; i < NUM_TESTS; i++) { + int aInt = random.nextInt(); + int bInt = random.nextInt(); + int intCompare = Integer.signum(Integer.compare(aInt, bInt)); + byte[] aBytes = ZOrderByteUtils.intToOrderedBytes(aInt); + byte[] bBytes = ZOrderByteUtils.intToOrderedBytes(bInt); + int byteCompare = Integer.signum(UnsignedBytes.lexicographicalComparator().compare(aBytes, bBytes)); + + Assert.assertEquals(String.format( + "Ordering of ints should match ordering of bytes, %s ~ %s -> %s != %s ~ %s -> %s ", + aInt, bInt, intCompare, Arrays.toString(aBytes), Arrays.toString(bBytes), byteCompare), + intCompare, byteCompare); + } + } + + @Test + public void testLongOrdering() { + for (int i = 0; i < NUM_TESTS; i++) { + long aLong = random.nextInt(); + long bLong = random.nextInt(); + int longCompare = Integer.signum(Long.compare(aLong, bLong)); + byte[] aBytes = ZOrderByteUtils.longToOrderBytes(aLong); + byte[] bBytes = ZOrderByteUtils.longToOrderBytes(bLong); + int byteCompare = Integer.signum(UnsignedBytes.lexicographicalComparator().compare(aBytes, bBytes)); + + Assert.assertEquals(String.format( + "Ordering of longs should match ordering of bytes, %s ~ %s -> %s != %s ~ %s -> %s ", + aLong, bLong, longCompare, Arrays.toString(aBytes), Arrays.toString(bBytes), byteCompare), + longCompare, byteCompare); + } + } + + @Test + public void testShortOrdering() { + for (int i = 0; i < NUM_TESTS; i++) { + short aShort = (short) (random.nextInt() % (Short.MAX_VALUE + 1)); + short bShort = (short) (random.nextInt() % (Short.MAX_VALUE + 1)); + int longCompare = Integer.signum(Long.compare(aShort, bShort)); + byte[] aBytes = ZOrderByteUtils.longToOrderBytes(aShort); + byte[] bBytes = ZOrderByteUtils.longToOrderBytes(bShort); + int byteCompare = Integer.signum(UnsignedBytes.lexicographicalComparator().compare(aBytes, bBytes)); + + Assert.assertEquals(String.format( + "Ordering of longs should match ordering of bytes, %s ~ %s -> %s != %s ~ %s -> %s ", + aShort, bShort, longCompare, Arrays.toString(aBytes), Arrays.toString(bBytes), byteCompare), + longCompare, byteCompare); + } + } + + @Test + public void testTinyOrdering() { + for (int i = 0; i < NUM_TESTS; i++) { + long aByte = (byte) (random.nextInt() % (Byte.MAX_VALUE + 1)); + long bByte = (byte) (random.nextInt() % (Byte.MAX_VALUE + 1)); + int longCompare = Integer.signum(Long.compare(aByte, bByte)); + byte[] aBytes = ZOrderByteUtils.longToOrderBytes(aByte); + byte[] bBytes = ZOrderByteUtils.longToOrderBytes(bByte); Review comment: I think those 2 should be `tinyintToOrderedBytes` ########## File path: core/src/test/java/org/apache/iceberg/util/TestZOrderByteUtil.java ########## @@ -0,0 +1,260 @@ +/* + * 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.iceberg.util; + +import java.util.Arrays; +import java.util.Random; +import org.apache.iceberg.relocated.com.google.common.primitives.UnsignedBytes; +import org.apache.iceberg.types.Types; +import org.junit.Assert; +import org.junit.Test; + +public class TestZOrderByteUtil { + private static final byte IIIIIIII = (byte) 255; + private static final byte IOIOIOIO = (byte) 170; + private static final byte OIOIOIOI = (byte) 85; + private static final byte OOOOIIII = (byte) 15; + private static final byte OOOOOOOI = (byte) 1; + private static final byte OOOOOOOO = (byte) 0; + + private static final int NUM_TESTS = 100000; + + private final Random random = new Random(42); + + private String bytesToString(byte[] bytes) { + StringBuilder result = new StringBuilder(); + for (byte b : bytes) { + result.append(String.format("%8s", Integer.toBinaryString(b & 0xFF)).replace(' ', '0')); + } + return result.toString(); + } + + /** + * Returns a non-0 length byte array + */ + private byte[] generateRandomBytes() { + int length = Math.abs(random.nextInt(100) + 1); + byte[] result = new byte[length]; + random.nextBytes(result); + return result; + } + + /** + * Test method to ensure correctness of byte interleaving code + */ + private String interleaveStrings(String[] strings) { + StringBuilder result = new StringBuilder(); + int totalLength = Arrays.stream(strings).mapToInt(String::length).sum(); + int substringIndex = 0; + int characterIndex = 0; + while (characterIndex < totalLength) { + for (String str : strings) { + if (substringIndex < str.length()) { + result.append(str.charAt(substringIndex)); + characterIndex++; + } + } + substringIndex++; + } + return result.toString(); + } + + /** + * Compares the result of a string based interleaving algorithm implemented above + * versus the binary bit-shifting algorithm used in ZOrderByteUtils. Either both + * algorithms are identically wrong or are both identically correct. + */ + @Test + public void testInterleaveRandomExamples() { + for (int test = 0; test < NUM_TESTS; test++) { + int numByteArrays = Math.abs(random.nextInt(6)) + 1; + byte[][] testBytes = new byte[numByteArrays][]; + String[] testStrings = new String[numByteArrays]; + for (int byteIndex = 0; byteIndex < numByteArrays; byteIndex++) { + testBytes[byteIndex] = generateRandomBytes(); + testStrings[byteIndex] = bytesToString(testBytes[byteIndex]); + } + byte[] byteResult = ZOrderByteUtils.interleaveBits(testBytes); + String byteResultAsString = bytesToString(byteResult); + + String stringResult = interleaveStrings(testStrings); + + Assert.assertEquals("String interleave didn't match byte interleave", stringResult, byteResultAsString); + } + } + + @Test + public void testInterleaveEmptyBits() { + byte[][] test = new byte[4][10]; + byte[] expected = new byte[40]; + + Assert.assertArrayEquals("Should combine empty arrays", + expected, ZOrderByteUtils.interleaveBits(test)); + } + + @Test + public void testInterleaveFullBits() { + byte[][] test = new byte[4][]; + test[0] = new byte[]{IIIIIIII, IIIIIIII}; + test[1] = new byte[]{IIIIIIII}; + test[2] = new byte[0]; + test[3] = new byte[]{IIIIIIII, IIIIIIII, IIIIIIII}; + byte[] expected = new byte[]{IIIIIIII, IIIIIIII, IIIIIIII, IIIIIIII, IIIIIIII, IIIIIIII}; + + Assert.assertArrayEquals("Should combine full arrays", + expected, ZOrderByteUtils.interleaveBits(test)); + } + + @Test + public void testInterleaveMixedBits() { + byte[][] test = new byte[4][]; + test[0] = new byte[]{OOOOOOOI, IIIIIIII, OOOOOOOO, OOOOIIII}; + test[1] = new byte[]{OOOOOOOI, OOOOOOOO, IIIIIIII}; + test[2] = new byte[]{OOOOOOOI}; + test[3] = new byte[]{OOOOOOOI}; + byte[] expected = new byte[]{ + OOOOOOOO, OOOOOOOO, OOOOOOOO, OOOOIIII, + IOIOIOIO, IOIOIOIO, + OIOIOIOI, OIOIOIOI, + OOOOIIII}; + Assert.assertArrayEquals("Should combine mixed byte arrays", + expected, ZOrderByteUtils.interleaveBits(test)); + } + + @Test + public void testIntOrdering() { + for (int i = 0; i < NUM_TESTS; i++) { + int aInt = random.nextInt(); + int bInt = random.nextInt(); + int intCompare = Integer.signum(Integer.compare(aInt, bInt)); + byte[] aBytes = ZOrderByteUtils.intToOrderedBytes(aInt); + byte[] bBytes = ZOrderByteUtils.intToOrderedBytes(bInt); + int byteCompare = Integer.signum(UnsignedBytes.lexicographicalComparator().compare(aBytes, bBytes)); + + Assert.assertEquals(String.format( + "Ordering of ints should match ordering of bytes, %s ~ %s -> %s != %s ~ %s -> %s ", + aInt, bInt, intCompare, Arrays.toString(aBytes), Arrays.toString(bBytes), byteCompare), + intCompare, byteCompare); + } + } + + @Test + public void testLongOrdering() { + for (int i = 0; i < NUM_TESTS; i++) { + long aLong = random.nextInt(); + long bLong = random.nextInt(); + int longCompare = Integer.signum(Long.compare(aLong, bLong)); + byte[] aBytes = ZOrderByteUtils.longToOrderBytes(aLong); + byte[] bBytes = ZOrderByteUtils.longToOrderBytes(bLong); + int byteCompare = Integer.signum(UnsignedBytes.lexicographicalComparator().compare(aBytes, bBytes)); + + Assert.assertEquals(String.format( + "Ordering of longs should match ordering of bytes, %s ~ %s -> %s != %s ~ %s -> %s ", + aLong, bLong, longCompare, Arrays.toString(aBytes), Arrays.toString(bBytes), byteCompare), + longCompare, byteCompare); + } + } + + @Test + public void testShortOrdering() { + for (int i = 0; i < NUM_TESTS; i++) { + short aShort = (short) (random.nextInt() % (Short.MAX_VALUE + 1)); + short bShort = (short) (random.nextInt() % (Short.MAX_VALUE + 1)); + int longCompare = Integer.signum(Long.compare(aShort, bShort)); + byte[] aBytes = ZOrderByteUtils.longToOrderBytes(aShort); + byte[] bBytes = ZOrderByteUtils.longToOrderBytes(bShort); Review comment: I think those 2 should both be `shortToOrderBytes` ########## File path: core/src/test/java/org/apache/iceberg/util/TestZOrderByteUtil.java ########## @@ -0,0 +1,260 @@ +/* + * 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.iceberg.util; + +import java.util.Arrays; +import java.util.Random; +import org.apache.iceberg.relocated.com.google.common.primitives.UnsignedBytes; +import org.apache.iceberg.types.Types; +import org.junit.Assert; +import org.junit.Test; + +public class TestZOrderByteUtil { + private static final byte IIIIIIII = (byte) 255; + private static final byte IOIOIOIO = (byte) 170; + private static final byte OIOIOIOI = (byte) 85; + private static final byte OOOOIIII = (byte) 15; + private static final byte OOOOOOOI = (byte) 1; + private static final byte OOOOOOOO = (byte) 0; + + private static final int NUM_TESTS = 100000; + + private final Random random = new Random(42); + + private String bytesToString(byte[] bytes) { + StringBuilder result = new StringBuilder(); + for (byte b : bytes) { + result.append(String.format("%8s", Integer.toBinaryString(b & 0xFF)).replace(' ', '0')); + } + return result.toString(); + } + + /** + * Returns a non-0 length byte array + */ + private byte[] generateRandomBytes() { + int length = Math.abs(random.nextInt(100) + 1); + byte[] result = new byte[length]; + random.nextBytes(result); + return result; + } + + /** + * Test method to ensure correctness of byte interleaving code + */ + private String interleaveStrings(String[] strings) { + StringBuilder result = new StringBuilder(); + int totalLength = Arrays.stream(strings).mapToInt(String::length).sum(); + int substringIndex = 0; + int characterIndex = 0; + while (characterIndex < totalLength) { + for (String str : strings) { + if (substringIndex < str.length()) { + result.append(str.charAt(substringIndex)); + characterIndex++; + } + } + substringIndex++; + } + return result.toString(); + } + + /** + * Compares the result of a string based interleaving algorithm implemented above + * versus the binary bit-shifting algorithm used in ZOrderByteUtils. Either both + * algorithms are identically wrong or are both identically correct. + */ + @Test + public void testInterleaveRandomExamples() { Review comment: takes 17-18 seconds to run on my local machine, just wondering whether we want to have such long running unit tests -- This is an automated message from the Apache Git Service. To respond to the message, please log on to GitHub and use the URL above to go to the specific comment. To unsubscribe, e-mail: [email protected] For queries about this service, please contact Infrastructure at: [email protected] --------------------------------------------------------------------- To unsubscribe, e-mail: [email protected] For additional commands, e-mail: [email protected]
