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Posted to commits@lucene.apache.org by gu...@apache.org on 2022/04/23 11:32:07 UTC

[lucene] branch main updated: LUCENE-10315: Speed up DocIdsWriter by ForUtil (#797)

This is an automated email from the ASF dual-hosted git repository.

guofeng pushed a commit to branch main
in repository https://gitbox.apache.org/repos/asf/lucene.git


The following commit(s) were added to refs/heads/main by this push:
     new 35ca2d79f73 LUCENE-10315: Speed up DocIdsWriter by ForUtil (#797)
35ca2d79f73 is described below

commit 35ca2d79f73c6dfaf5e648fe241f7e0b37084a90
Author: gf2121 <52...@users.noreply.github.com>
AuthorDate: Sat Apr 23 19:32:02 2022 +0800

    LUCENE-10315: Speed up DocIdsWriter by ForUtil (#797)
---
 lucene/CHANGES.txt                                 |   2 +
 .../store/EndiannessReverserIndexInput.java        |   8 +
 .../org/apache/lucene/store/ByteBufferGuard.java   |   6 +
 .../apache/lucene/store/ByteBufferIndexInput.java  |  36 ++++
 .../java/org/apache/lucene/store/DataInput.java    |  14 ++
 .../java/org/apache/lucene/util/bkd/BKDReader.java |   8 +-
 .../java/org/apache/lucene/util/bkd/BKDWriter.java |   5 +-
 .../org/apache/lucene/util/bkd/DocIdsWriter.java   | 185 +++++++++++++--------
 .../apache/lucene/util/bkd/TestDocIdsWriter.java   |  22 ++-
 .../lucene/tests/store/BaseDirectoryTestCase.java  |  59 +++++++
 10 files changed, 267 insertions(+), 78 deletions(-)

diff --git a/lucene/CHANGES.txt b/lucene/CHANGES.txt
index fdacfdb6687..c2c1fcd6cd4 100644
--- a/lucene/CHANGES.txt
+++ b/lucene/CHANGES.txt
@@ -119,6 +119,8 @@ Optimizations
 * LUCENE-10503: Potential speedup for pure disjunctions whose clauses produce
   scores that are very close to each other. (Adrien Grand)
 
+* LUCENE-10315: Use SIMD instructions to decode BKD doc IDs. (Guo Feng, Adrien Grand, Ignacio Vera)
+
 Bug Fixes
 ---------------------
 * LUCENE-10477: Highlighter: WeightedSpanTermExtractor.extractWeightedSpanTerms to Query#rewrite
diff --git a/lucene/backward-codecs/src/java/org/apache/lucene/backward_codecs/store/EndiannessReverserIndexInput.java b/lucene/backward-codecs/src/java/org/apache/lucene/backward_codecs/store/EndiannessReverserIndexInput.java
index d7d0b76853e..4a1c0566ffc 100644
--- a/lucene/backward-codecs/src/java/org/apache/lucene/backward_codecs/store/EndiannessReverserIndexInput.java
+++ b/lucene/backward-codecs/src/java/org/apache/lucene/backward_codecs/store/EndiannessReverserIndexInput.java
@@ -80,6 +80,14 @@ final class EndiannessReverserIndexInput extends IndexInput {
     }
   }
 
+  @Override
+  public void readInts(int[] dst, int offset, int length) throws IOException {
+    in.readInts(dst, offset, length);
+    for (int i = 0; i < length; ++i) {
+      dst[offset + i] = Integer.reverseBytes(dst[offset + i]);
+    }
+  }
+
   @Override
   public void readFloats(float[] dst, int offset, int length) throws IOException {
     in.readFloats(dst, offset, length);
diff --git a/lucene/core/src/java/org/apache/lucene/store/ByteBufferGuard.java b/lucene/core/src/java/org/apache/lucene/store/ByteBufferGuard.java
index 68658d64ee8..2d75597f9de 100644
--- a/lucene/core/src/java/org/apache/lucene/store/ByteBufferGuard.java
+++ b/lucene/core/src/java/org/apache/lucene/store/ByteBufferGuard.java
@@ -19,6 +19,7 @@ package org.apache.lucene.store;
 import java.io.IOException;
 import java.nio.ByteBuffer;
 import java.nio.FloatBuffer;
+import java.nio.IntBuffer;
 import java.nio.LongBuffer;
 import java.util.concurrent.atomic.AtomicInteger;
 
@@ -138,6 +139,11 @@ final class ByteBufferGuard {
     receiver.get(dst, offset, length);
   }
 
+  public void getInts(IntBuffer receiver, int[] dst, int offset, int length) {
+    ensureValid();
+    receiver.get(dst, offset, length);
+  }
+
   public void getFloats(FloatBuffer receiver, float[] dst, int offset, int length) {
     ensureValid();
     receiver.get(dst, offset, length);
diff --git a/lucene/core/src/java/org/apache/lucene/store/ByteBufferIndexInput.java b/lucene/core/src/java/org/apache/lucene/store/ByteBufferIndexInput.java
index 8469b987010..3229cde0845 100644
--- a/lucene/core/src/java/org/apache/lucene/store/ByteBufferIndexInput.java
+++ b/lucene/core/src/java/org/apache/lucene/store/ByteBufferIndexInput.java
@@ -22,6 +22,7 @@ import java.nio.BufferUnderflowException;
 import java.nio.ByteBuffer;
 import java.nio.ByteOrder;
 import java.nio.FloatBuffer;
+import java.nio.IntBuffer;
 import java.nio.LongBuffer;
 
 /**
@@ -36,6 +37,7 @@ import java.nio.LongBuffer;
 public abstract class ByteBufferIndexInput extends IndexInput implements RandomAccessInput {
   private static final FloatBuffer EMPTY_FLOATBUFFER = FloatBuffer.allocate(0);
   private static final LongBuffer EMPTY_LONGBUFFER = LongBuffer.allocate(0);
+  private static final IntBuffer EMPTY_INTBUFFER = IntBuffer.allocate(0);
 
   protected final long length;
   protected final long chunkSizeMask;
@@ -46,6 +48,7 @@ public abstract class ByteBufferIndexInput extends IndexInput implements RandomA
   protected int curBufIndex = -1;
   protected ByteBuffer curBuf; // redundant for speed: buffers[curBufIndex]
   private LongBuffer[] curLongBufferViews;
+  private IntBuffer[] curIntBufferViews;
   private FloatBuffer[] curFloatBufferViews;
 
   protected boolean isClone = false;
@@ -83,6 +86,7 @@ public abstract class ByteBufferIndexInput extends IndexInput implements RandomA
     this.curBuf = curBuf;
     curLongBufferViews = null;
     curFloatBufferViews = null;
+    curIntBufferViews = null;
   }
 
   @Override
@@ -176,6 +180,37 @@ public abstract class ByteBufferIndexInput extends IndexInput implements RandomA
     }
   }
 
+  @Override
+  public void readInts(int[] dst, int offset, int length) throws IOException {
+    // See notes about readLongs above
+    if (curIntBufferViews == null) {
+      curIntBufferViews = new IntBuffer[Integer.BYTES];
+      for (int i = 0; i < Integer.BYTES; ++i) {
+        if (i < curBuf.limit()) {
+          curIntBufferViews[i] =
+              curBuf.duplicate().position(i).order(ByteOrder.LITTLE_ENDIAN).asIntBuffer();
+        } else {
+          curIntBufferViews[i] = EMPTY_INTBUFFER;
+        }
+      }
+    }
+    try {
+      final int position = curBuf.position();
+      guard.getInts(
+          curIntBufferViews[position & 0x03].position(position >>> 2), dst, offset, length);
+      // if the above call succeeded, then we know the below sum cannot overflow
+      curBuf.position(position + (length << 2));
+    } catch (
+        @SuppressWarnings("unused")
+        BufferUnderflowException e) {
+      super.readInts(dst, offset, length);
+    } catch (
+        @SuppressWarnings("unused")
+        NullPointerException npe) {
+      throw new AlreadyClosedException("Already closed: " + this);
+    }
+  }
+
   @Override
   public final void readFloats(float[] floats, int offset, int len) throws IOException {
     // See notes about readLongs above
@@ -503,6 +538,7 @@ public abstract class ByteBufferIndexInput extends IndexInput implements RandomA
     curBuf = null;
     curBufIndex = 0;
     curLongBufferViews = null;
+    curIntBufferViews = null;
   }
 
   /** Optimization of ByteBufferIndexInput for when there is only one buffer */
diff --git a/lucene/core/src/java/org/apache/lucene/store/DataInput.java b/lucene/core/src/java/org/apache/lucene/store/DataInput.java
index d935cb3930d..cfb39e7593f 100644
--- a/lucene/core/src/java/org/apache/lucene/store/DataInput.java
+++ b/lucene/core/src/java/org/apache/lucene/store/DataInput.java
@@ -169,6 +169,20 @@ public abstract class DataInput implements Cloneable {
     }
   }
 
+  /**
+   * Reads a specified number of ints into an array at the specified offset.
+   *
+   * @param dst the array to read bytes into
+   * @param offset the offset in the array to start storing ints
+   * @param length the number of ints to read
+   */
+  public void readInts(int[] dst, int offset, int length) throws IOException {
+    Objects.checkFromIndexSize(offset, length, dst.length);
+    for (int i = 0; i < length; ++i) {
+      dst[offset + i] = readInt();
+    }
+  }
+
   /**
    * Reads a specified number of floats into an array at the specified offset.
    *
diff --git a/lucene/core/src/java/org/apache/lucene/util/bkd/BKDReader.java b/lucene/core/src/java/org/apache/lucene/util/bkd/BKDReader.java
index ac55f33fb1e..d2d326b3a15 100644
--- a/lucene/core/src/java/org/apache/lucene/util/bkd/BKDReader.java
+++ b/lucene/core/src/java/org/apache/lucene/util/bkd/BKDReader.java
@@ -217,6 +217,7 @@ public class BKDReader extends PointValues {
         scratchMaxIndexPackedValue;
     private final int[] commonPrefixLengths;
     private final BKDReaderDocIDSetIterator scratchIterator;
+    private final DocIdsWriter docIdsWriter;
     // if true the tree is balanced, otherwise unbalanced
     private final boolean isTreeBalanced;
 
@@ -303,6 +304,7 @@ public class BKDReader extends PointValues {
       this.scratchDataPackedValue = scratchDataPackedValue;
       this.scratchMinIndexPackedValue = scratchMinIndexPackedValue;
       this.scratchMaxIndexPackedValue = scratchMaxIndexPackedValue;
+      this.docIdsWriter = scratchIterator.docIdsWriter;
     }
 
     @Override
@@ -570,7 +572,7 @@ public class BKDReader extends PointValues {
         // How many points are stored in this leaf cell:
         int count = leafNodes.readVInt();
         // No need to call grow(), it has been called up-front
-        DocIdsWriter.readInts(leafNodes, count, visitor);
+        docIdsWriter.readInts(leafNodes, count, visitor);
       } else {
         pushLeft();
         addAll(visitor, grown);
@@ -633,7 +635,7 @@ public class BKDReader extends PointValues {
       // How many points are stored in this leaf cell:
       int count = in.readVInt();
 
-      DocIdsWriter.readInts(in, count, iterator.docIDs);
+      docIdsWriter.readInts(in, count, iterator.docIDs);
 
       return count;
     }
@@ -1002,9 +1004,11 @@ public class BKDReader extends PointValues {
     private int offset;
     private int docID;
     final int[] docIDs;
+    private final DocIdsWriter docIdsWriter;
 
     public BKDReaderDocIDSetIterator(int maxPointsInLeafNode) {
       this.docIDs = new int[maxPointsInLeafNode];
+      this.docIdsWriter = new DocIdsWriter(maxPointsInLeafNode);
     }
 
     @Override
diff --git a/lucene/core/src/java/org/apache/lucene/util/bkd/BKDWriter.java b/lucene/core/src/java/org/apache/lucene/util/bkd/BKDWriter.java
index e2c37c89b35..6f58944622a 100644
--- a/lucene/core/src/java/org/apache/lucene/util/bkd/BKDWriter.java
+++ b/lucene/core/src/java/org/apache/lucene/util/bkd/BKDWriter.java
@@ -130,6 +130,7 @@ public class BKDWriter implements Closeable {
   private final long totalPointCount;
 
   private final int maxDoc;
+  private final DocIdsWriter docIdsWriter;
 
   public BKDWriter(
       int maxDoc,
@@ -165,7 +166,7 @@ public class BKDWriter implements Closeable {
 
     // Maximum number of points we hold in memory at any time
     maxPointsSortInHeap = (int) ((maxMBSortInHeap * 1024 * 1024) / (config.bytesPerDoc));
-
+    docIdsWriter = new DocIdsWriter(config.maxPointsInLeafNode);
     // Finally, we must be able to hold at least the leaf node in heap during build:
     if (maxPointsSortInHeap < config.maxPointsInLeafNode) {
       throw new IllegalArgumentException(
@@ -1288,7 +1289,7 @@ public class BKDWriter implements Closeable {
       throws IOException {
     assert count > 0 : "config.maxPointsInLeafNode=" + config.maxPointsInLeafNode;
     out.writeVInt(count);
-    DocIdsWriter.writeDocIds(docIDs, start, count, out);
+    docIdsWriter.writeDocIds(docIDs, start, count, out);
   }
 
   private void writeLeafBlockPackedValues(
diff --git a/lucene/core/src/java/org/apache/lucene/util/bkd/DocIdsWriter.java b/lucene/core/src/java/org/apache/lucene/util/bkd/DocIdsWriter.java
index 4e274159188..40db4c0069d 100644
--- a/lucene/core/src/java/org/apache/lucene/util/bkd/DocIdsWriter.java
+++ b/lucene/core/src/java/org/apache/lucene/util/bkd/DocIdsWriter.java
@@ -24,31 +24,43 @@ import org.apache.lucene.store.IndexInput;
 import org.apache.lucene.util.DocBaseBitSetIterator;
 import org.apache.lucene.util.FixedBitSet;
 
-class DocIdsWriter {
+final class DocIdsWriter {
 
-  private DocIdsWriter() {}
+  private static final byte CONTINUOUS_IDS = (byte) -2;
+  private static final byte BITSET_IDS = (byte) -1;
+  private static final byte DELTA_BPV_16 = (byte) 16;
+  private static final byte BPV_24 = (byte) 24;
+  private static final byte BPV_32 = (byte) 32;
+  // These signs are legacy, should no longer be used in the writing side.
+  private static final byte LEGACY_DELTA_VINT = (byte) 0;
 
-  static void writeDocIds(int[] docIds, int start, int count, DataOutput out) throws IOException {
+  private final int[] scratch;
+
+  DocIdsWriter(int maxPointsInLeaf) {
+    scratch = new int[maxPointsInLeaf];
+  }
+
+  void writeDocIds(int[] docIds, int start, int count, DataOutput out) throws IOException {
     // docs can be sorted either when all docs in a block have the same value
     // or when a segment is sorted
-    boolean sorted = true;
     boolean strictlySorted = true;
+    int min = docIds[0];
+    int max = docIds[0];
     for (int i = 1; i < count; ++i) {
       int last = docIds[start + i - 1];
       int current = docIds[start + i];
-      if (last > current) {
-        sorted = strictlySorted = false;
-        break;
-      } else if (last == current) {
+      if (last >= current) {
         strictlySorted = false;
       }
+      min = Math.min(min, current);
+      max = Math.max(max, current);
     }
 
-    int min2max = docIds[start + count - 1] - docIds[start] + 1;
+    int min2max = max - min + 1;
     if (strictlySorted) {
       if (min2max == count) {
         // continuous ids, typically happens when segment is sorted
-        out.writeByte((byte) -2);
+        out.writeByte(CONTINUOUS_IDS);
         out.writeVInt(docIds[start]);
         return;
       } else if (min2max <= (count << 4)) {
@@ -56,26 +68,31 @@ class DocIdsWriter {
         // Only trigger bitset optimization when max - min + 1 <= 16 * count in order to avoid
         // expanding too much storage.
         // A field with lower cardinality will have higher probability to trigger this optimization.
-        out.writeByte((byte) -1);
+        out.writeByte(BITSET_IDS);
         writeIdsAsBitSet(docIds, start, count, out);
         return;
       }
     }
-    if (sorted) {
-      out.writeByte((byte) 0);
-      int previous = 0;
-      for (int i = 0; i < count; ++i) {
-        int doc = docIds[start + i];
-        out.writeVInt(doc - previous);
-        previous = doc;
+
+    if (min2max <= 0xFFFF) {
+      out.writeByte(DELTA_BPV_16);
+      for (int i = 0; i < count; i++) {
+        scratch[i] = docIds[start + i] - min;
       }
-    } else {
-      long max = 0;
-      for (int i = 0; i < count; ++i) {
-        max |= Integer.toUnsignedLong(docIds[start + i]);
+      out.writeVInt(min);
+      final int halfLen = count >>> 1;
+      for (int i = 0; i < halfLen; ++i) {
+        scratch[i] = scratch[halfLen + i] | (scratch[i] << 16);
+      }
+      for (int i = 0; i < halfLen; i++) {
+        out.writeInt(scratch[i]);
       }
-      if (max <= 0xffffff) {
-        out.writeByte((byte) 24);
+      if ((count & 1) == 1) {
+        out.writeShort((short) scratch[count - 1]);
+      }
+    } else {
+      if (max <= 0xFFFFFF) {
+        out.writeByte(BPV_24);
         // write them the same way we are reading them.
         int i;
         for (i = 0; i < count - 7; i += 8) {
@@ -103,8 +120,8 @@ class DocIdsWriter {
           out.writeByte((byte) docIds[start + i]);
         }
       } else {
-        out.writeByte((byte) 32);
-        for (int i = 0; i < count; ++i) {
+        out.writeByte(BPV_32);
+        for (int i = 0; i < count; i++) {
           out.writeInt(docIds[start + i]);
         }
       }
@@ -145,23 +162,26 @@ class DocIdsWriter {
   }
 
   /** Read {@code count} integers into {@code docIDs}. */
-  static void readInts(IndexInput in, int count, int[] docIDs) throws IOException {
+  void readInts(IndexInput in, int count, int[] docIDs) throws IOException {
     final int bpv = in.readByte();
     switch (bpv) {
-      case -2:
+      case CONTINUOUS_IDS:
         readContinuousIds(in, count, docIDs);
         break;
-      case -1:
+      case BITSET_IDS:
         readBitSet(in, count, docIDs);
         break;
-      case 0:
-        readDeltaVInts(in, count, docIDs);
+      case DELTA_BPV_16:
+        readDelta16(in, count, docIDs);
         break;
-      case 32:
+      case BPV_24:
+        readInts24(in, count, docIDs);
+        break;
+      case BPV_32:
         readInts32(in, count, docIDs);
         break;
-      case 24:
-        readInts24(in, count, docIDs);
+      case LEGACY_DELTA_VINT:
+        readLegacyDeltaVInts(in, count, docIDs);
         break;
       default:
         throw new IOException("Unsupported number of bits per value: " + bpv);
@@ -184,6 +204,15 @@ class DocIdsWriter {
     }
   }
 
+  private static void readLegacyDeltaVInts(IndexInput in, int count, int[] docIDs)
+      throws IOException {
+    int doc = 0;
+    for (int i = 0; i < count; i++) {
+      doc += in.readVInt();
+      docIDs[i] = doc;
+    }
+  }
+
   private static void readBitSet(IndexInput in, int count, int[] docIDs) throws IOException {
     DocIdSetIterator iterator = readBitSetIterator(in, count);
     int docId, pos = 0;
@@ -193,17 +222,17 @@ class DocIdsWriter {
     assert pos == count : "pos: " + pos + "count: " + count;
   }
 
-  private static void readDeltaVInts(IndexInput in, int count, int[] docIDs) throws IOException {
-    int doc = 0;
-    for (int i = 0; i < count; i++) {
-      doc += in.readVInt();
-      docIDs[i] = doc;
+  private static void readDelta16(IndexInput in, int count, int[] docIDs) throws IOException {
+    final int min = in.readVInt();
+    final int halfLen = count >>> 1;
+    in.readInts(docIDs, 0, halfLen);
+    for (int i = 0; i < halfLen; ++i) {
+      int l = docIDs[i];
+      docIDs[i] = (l >>> 16) + min;
+      docIDs[halfLen + i] = (l & 0xFFFF) + min;
     }
-  }
-
-  private static void readInts32(IndexInput in, int count, int[] docIDs) throws IOException {
-    for (int i = 0; i < count; i++) {
-      docIDs[i] = in.readInt();
+    if ((count & 1) == 1) {
+      docIDs[count - 1] = Short.toUnsignedInt(in.readShort()) + min;
     }
   }
 
@@ -227,34 +256,58 @@ class DocIdsWriter {
     }
   }
 
+  private static void readInts32(IndexInput in, int count, int[] docIDs) throws IOException {
+    in.readInts(docIDs, 0, count);
+  }
+
   /**
    * Read {@code count} integers and feed the result directly to {@link
    * IntersectVisitor#visit(int)}.
    */
-  static void readInts(IndexInput in, int count, IntersectVisitor visitor) throws IOException {
+  void readInts(IndexInput in, int count, IntersectVisitor visitor) throws IOException {
     final int bpv = in.readByte();
     switch (bpv) {
-      case -2:
+      case CONTINUOUS_IDS:
         readContinuousIds(in, count, visitor);
         break;
-      case -1:
+      case BITSET_IDS:
         readBitSet(in, count, visitor);
         break;
-      case 0:
-        readDeltaVInts(in, count, visitor);
+      case DELTA_BPV_16:
+        readDelta16(in, count, visitor);
         break;
-      case 32:
+      case BPV_24:
+        readInts24(in, count, visitor);
+        break;
+      case BPV_32:
         readInts32(in, count, visitor);
         break;
-      case 24:
-        readInts24(in, count, visitor);
+      case LEGACY_DELTA_VINT:
+        readLegacyDeltaVInts(in, count, visitor);
         break;
       default:
         throw new IOException("Unsupported number of bits per value: " + bpv);
     }
   }
 
-  private static void readDeltaVInts(IndexInput in, int count, IntersectVisitor visitor)
+  private static void readBitSet(IndexInput in, int count, IntersectVisitor visitor)
+      throws IOException {
+    DocIdSetIterator bitSetIterator = readBitSetIterator(in, count);
+    visitor.visit(bitSetIterator);
+  }
+
+  private static void readContinuousIds(IndexInput in, int count, IntersectVisitor visitor)
+      throws IOException {
+    int start = in.readVInt();
+    int extra = start & 63;
+    int offset = start - extra;
+    int numBits = count + extra;
+    FixedBitSet bitSet = new FixedBitSet(numBits);
+    bitSet.set(extra, numBits);
+    visitor.visit(new DocBaseBitSetIterator(bitSet, count, offset));
+  }
+
+  private static void readLegacyDeltaVInts(IndexInput in, int count, IntersectVisitor visitor)
       throws IOException {
     int doc = 0;
     for (int i = 0; i < count; i++) {
@@ -263,10 +316,10 @@ class DocIdsWriter {
     }
   }
 
-  private static void readInts32(IndexInput in, int count, IntersectVisitor visitor)
-      throws IOException {
+  private void readDelta16(IndexInput in, int count, IntersectVisitor visitor) throws IOException {
+    readDelta16(in, count, scratch);
     for (int i = 0; i < count; i++) {
-      visitor.visit(in.readInt());
+      visitor.visit(scratch[i]);
     }
   }
 
@@ -291,20 +344,10 @@ class DocIdsWriter {
     }
   }
 
-  private static void readBitSet(IndexInput in, int count, IntersectVisitor visitor)
-      throws IOException {
-    DocIdSetIterator bitSetIterator = readBitSetIterator(in, count);
-    visitor.visit(bitSetIterator);
-  }
-
-  private static void readContinuousIds(IndexInput in, int count, IntersectVisitor visitor)
-      throws IOException {
-    int start = in.readVInt();
-    int extra = start & 63;
-    int offset = start - extra;
-    int numBits = count + extra;
-    FixedBitSet bitSet = new FixedBitSet(numBits);
-    bitSet.set(extra, numBits);
-    visitor.visit(new DocBaseBitSetIterator(bitSet, count, offset));
+  private void readInts32(IndexInput in, int count, IntersectVisitor visitor) throws IOException {
+    in.readInts(scratch, 0, count);
+    for (int i = 0; i < count; i++) {
+      visitor.visit(scratch[i]);
+    }
   }
 }
diff --git a/lucene/core/src/test/org/apache/lucene/util/bkd/TestDocIdsWriter.java b/lucene/core/src/test/org/apache/lucene/util/bkd/TestDocIdsWriter.java
index 5b2281d6b36..7409c71821c 100644
--- a/lucene/core/src/test/org/apache/lucene/util/bkd/TestDocIdsWriter.java
+++ b/lucene/core/src/test/org/apache/lucene/util/bkd/TestDocIdsWriter.java
@@ -60,6 +60,21 @@ public class TestDocIdsWriter extends LuceneTestCase {
     }
   }
 
+  public void testCluster() throws Exception {
+    int numIters = atLeast(100);
+    try (Directory dir = newDirectory()) {
+      for (int iter = 0; iter < numIters; ++iter) {
+        int[] docIDs = new int[1 + random().nextInt(5000)];
+        int min = random().nextInt(1000);
+        final int bpv = TestUtil.nextInt(random(), 1, 16);
+        for (int i = 0; i < docIDs.length; ++i) {
+          docIDs[i] = min + TestUtil.nextInt(random(), 0, (1 << bpv) - 1);
+        }
+        test(dir, docIDs);
+      }
+    }
+  }
+
   public void testBitSet() throws Exception {
     int numIters = atLeast(100);
     try (Directory dir = newDirectory()) {
@@ -93,8 +108,9 @@ public class TestDocIdsWriter extends LuceneTestCase {
 
   private void test(Directory dir, int[] ints) throws Exception {
     final long len;
+    DocIdsWriter docIdsWriter = new DocIdsWriter(ints.length);
     try (IndexOutput out = dir.createOutput("tmp", IOContext.DEFAULT)) {
-      DocIdsWriter.writeDocIds(ints, 0, ints.length, out);
+      docIdsWriter.writeDocIds(ints, 0, ints.length, out);
       len = out.getFilePointer();
       if (random().nextBoolean()) {
         out.writeLong(0); // garbage
@@ -102,13 +118,13 @@ public class TestDocIdsWriter extends LuceneTestCase {
     }
     try (IndexInput in = dir.openInput("tmp", IOContext.READONCE)) {
       int[] read = new int[ints.length];
-      DocIdsWriter.readInts(in, ints.length, read);
+      docIdsWriter.readInts(in, ints.length, read);
       assertArrayEquals(ints, read);
       assertEquals(len, in.getFilePointer());
     }
     try (IndexInput in = dir.openInput("tmp", IOContext.READONCE)) {
       int[] read = new int[ints.length];
-      DocIdsWriter.readInts(
+      docIdsWriter.readInts(
           in,
           ints.length,
           new IntersectVisitor() {
diff --git a/lucene/test-framework/src/java/org/apache/lucene/tests/store/BaseDirectoryTestCase.java b/lucene/test-framework/src/java/org/apache/lucene/tests/store/BaseDirectoryTestCase.java
index 81b39f712bf..d91671bb929 100644
--- a/lucene/test-framework/src/java/org/apache/lucene/tests/store/BaseDirectoryTestCase.java
+++ b/lucene/test-framework/src/java/org/apache/lucene/tests/store/BaseDirectoryTestCase.java
@@ -243,6 +243,65 @@ public abstract class BaseDirectoryTestCase extends LuceneTestCase {
     }
   }
 
+  public void testAlignedInts() throws Exception {
+    try (Directory dir = getDirectory(createTempDir("testAlignedInts"))) {
+      try (IndexOutput out = dir.createOutput("Ints", newIOContext(random()))) {
+        out.writeInt(3);
+        out.writeInt(Integer.MAX_VALUE);
+        out.writeInt(-3);
+      }
+      try (IndexInput input = dir.openInput("Ints", newIOContext(random()))) {
+        assertEquals(12, input.length());
+        int[] i = new int[4];
+        input.readInts(i, 1, 3);
+        assertArrayEquals(new int[] {0, 3, Integer.MAX_VALUE, -3}, i);
+        assertEquals(12, input.getFilePointer());
+      }
+    }
+  }
+
+  public void testUnalignedInts() throws Exception {
+    int padding = random().nextInt(3) + 1;
+    try (Directory dir = getDirectory(createTempDir("testUnalignedInts"))) {
+      try (IndexOutput out = dir.createOutput("Ints", newIOContext(random()))) {
+        for (int i = 0; i < padding; i++) {
+          out.writeByte((byte) 2);
+        }
+        out.writeInt(3);
+        out.writeInt(Integer.MAX_VALUE);
+        out.writeInt(-3);
+      }
+      try (IndexInput input = dir.openInput("Ints", newIOContext(random()))) {
+        assertEquals(12 + padding, input.length());
+        for (int i = 0; i < padding; i++) {
+          assertEquals(2, input.readByte());
+        }
+        int[] i = new int[4];
+        input.readInts(i, 1, 3);
+        assertArrayEquals(new int[] {0, 3, Integer.MAX_VALUE, -3}, i);
+        assertEquals(12 + padding, input.getFilePointer());
+      }
+    }
+  }
+
+  public void testIntsUnderflow() throws Exception {
+    try (Directory dir = getDirectory(createTempDir("testIntsUnderflow"))) {
+      final int offset = random().nextInt(4);
+      final int length = TestUtil.nextInt(random(), 1, 16);
+      try (IndexOutput out = dir.createOutput("Ints", newIOContext(random()))) {
+        byte[] b =
+            new byte
+                [offset + length * Integer.BYTES - TestUtil.nextInt(random(), 1, Integer.BYTES)];
+        random().nextBytes(b);
+        out.writeBytes(b, b.length);
+      }
+      try (IndexInput input = dir.openInput("Ints", newIOContext(random()))) {
+        input.seek(offset);
+        expectThrows(EOFException.class, () -> input.readInts(new int[length], 0, length));
+      }
+    }
+  }
+
   public void testAlignedFloats() throws Exception {
     try (Directory dir = getDirectory(createTempDir("testAlignedFloats"))) {
       try (IndexOutput out = dir.createOutput("Floats", newIOContext(random()))) {