diff --git a/code/features-index/index-reverse/src/test/java/nu/marginalia/index/construction/ReversePreindexFinalizeTest.java b/code/features-index/index-reverse/src/test/java/nu/marginalia/index/construction/ReversePreindexFinalizeTest.java
index 7a9f3996..882bc34a 100644
--- a/code/features-index/index-reverse/src/test/java/nu/marginalia/index/construction/ReversePreindexFinalizeTest.java
+++ b/code/features-index/index-reverse/src/test/java/nu/marginalia/index/construction/ReversePreindexFinalizeTest.java
@@ -107,8 +107,8 @@ class ReversePreindexFinalizeTest {
         System.out.println(Files.size(wordsFile));
         System.out.println(Files.size(docsFile));
 
-        var docsArray = LongArray.mmapRead(docsFile);
-        var wordsArray = LongArray.mmapRead(wordsFile);
+        var docsArray = LongArrayFactory.mmapForReadingConfined(docsFile);
+        var wordsArray = LongArrayFactory.mmapForReadingConfined(wordsFile);
 
 
         var wordsHeader = BTreeReader.readHeader(wordsArray, 0);
diff --git a/code/libraries/array/src/main/java/nu/marginalia/array/LongArray.java b/code/libraries/array/src/main/java/nu/marginalia/array/LongArray.java
index cdb44b48..bfb05ce0 100644
--- a/code/libraries/array/src/main/java/nu/marginalia/array/LongArray.java
+++ b/code/libraries/array/src/main/java/nu/marginalia/array/LongArray.java
@@ -59,10 +59,10 @@ public interface LongArray extends LongArrayBase, LongArrayTransformations, Long
         return PagingLongArray.mapFileReadWrite(DEFAULT_PARTITIONING_SCHEME, path, size);
     }
 
-    default ShiftedLongArray shifted(long offset) {
+    default LongArray shifted(long offset) {
         return new ShiftedLongArray(offset, this);
     }
-    default ShiftedLongArray range(long start, long end) {
+    default LongArray range(long start, long end) {
         return new ShiftedLongArray(start, end, this);
     }
 
diff --git a/code/libraries/array/src/main/java/nu/marginalia/array/page/PagingLongArray.java b/code/libraries/array/src/main/java/nu/marginalia/array/page/PagingLongArray.java
index c26bafe4..923c4ff1 100644
--- a/code/libraries/array/src/main/java/nu/marginalia/array/page/PagingLongArray.java
+++ b/code/libraries/array/src/main/java/nu/marginalia/array/page/PagingLongArray.java
@@ -547,7 +547,7 @@ public class PagingLongArray extends AbstractPagingArray<LongArrayPage, LongBuff
         return pages[partitioningScheme.getPage(forOffset)];
     }
 
-    public ShiftedLongArray range(long start, long end) {
+    public LongArray range(long start, long end) {
         if (partitioningScheme.isSamePage(start, end)) {
             return pages[partitioningScheme.getPage(start)]
                     .range(partitioningScheme.getOffset(start),
diff --git a/code/libraries/array/src/main/java/nu/marginalia/array/page/SegmentLongArray.java b/code/libraries/array/src/main/java/nu/marginalia/array/page/SegmentLongArray.java
index edb6a95a..fffdcf2b 100644
--- a/code/libraries/array/src/main/java/nu/marginalia/array/page/SegmentLongArray.java
+++ b/code/libraries/array/src/main/java/nu/marginalia/array/page/SegmentLongArray.java
@@ -8,7 +8,6 @@ import javax.annotation.Nullable;
 import java.io.IOException;
 import java.lang.foreign.Arena;
 import java.lang.foreign.MemorySegment;
-import java.lang.foreign.ValueLayout;
 import java.nio.ByteBuffer;
 import java.nio.LongBuffer;
 import java.nio.channels.FileChannel;
@@ -17,6 +16,8 @@ import java.nio.file.OpenOption;
 import java.nio.file.Path;
 import java.nio.file.StandardOpenOption;
 
+import static java.lang.foreign.ValueLayout.JAVA_LONG;
+
 public class SegmentLongArray implements PartitionPage, LongArray {
 
     @Nullable
@@ -58,8 +59,8 @@ public class SegmentLongArray implements PartitionPage, LongArray {
         try (var channel = (FileChannel) Files.newByteChannel(file, openOptions)) {
 
             return channel.map(mode,
-                            WORD_SIZE * offset,
-                            WORD_SIZE * size,
+                            JAVA_LONG.byteSize() * offset,
+                            JAVA_LONG.byteSize() * size,
                             arena);
         }
         catch (IOException ex) {
@@ -67,10 +68,26 @@ public class SegmentLongArray implements PartitionPage, LongArray {
         }
     }
 
+    @Override
+    public LongArray range(long start, long end) {
+        return new SegmentLongArray(
+            segment.asSlice(
+                start * JAVA_LONG.byteSize(),
+                (end-start) * JAVA_LONG.byteSize()),
+            null);
+    }
+
+    @Override
+    public LongArray shifted(long start) {
+        return new SegmentLongArray(
+                segment.asSlice(start * JAVA_LONG.byteSize()),
+            null);
+    }
+
     @Override
     public long get(long at) {
         try {
-            return segment.getAtIndex(ValueLayout.JAVA_LONG, at);
+            return segment.getAtIndex(JAVA_LONG, at);
         }
         catch (IndexOutOfBoundsException ex) {
             throw new IndexOutOfBoundsException("@" + at + "(" + 0 + ":" + segment.byteSize()/8 + ")");
@@ -80,13 +97,13 @@ public class SegmentLongArray implements PartitionPage, LongArray {
     @Override
     public void get(long start, long end, long[] buffer) {
         for (int i = 0; i < end - start; i++) {
-            buffer[i] = segment.getAtIndex(ValueLayout.JAVA_LONG, start + i);
+            buffer[i] = segment.getAtIndex(JAVA_LONG, start + i);
         }
     }
 
     @Override
     public void set(long at, long val) {
-        segment.setAtIndex(ValueLayout.JAVA_LONG, at, val);
+        segment.setAtIndex(JAVA_LONG, at, val);
     }
 
     @Override
@@ -106,7 +123,7 @@ public class SegmentLongArray implements PartitionPage, LongArray {
 
     @Override
     public long size() {
-        return segment.byteSize() / 8;
+        return segment.byteSize() / JAVA_LONG.byteSize();
     }
 
     @Override
@@ -135,12 +152,12 @@ public class SegmentLongArray implements PartitionPage, LongArray {
     @Override
     public void transferFrom(FileChannel source, long sourceStart, long arrayStart, long arrayEnd) throws IOException {
 
-        long index = arrayStart * WORD_SIZE;
-        long length = (arrayEnd - arrayStart) * WORD_SIZE;
+        long index = arrayStart * JAVA_LONG.byteSize();
+        long length = (arrayEnd - arrayStart) * JAVA_LONG.byteSize();
 
         var bufferSlice = segment.asSlice(index, length).asByteBuffer();
 
-        long startPos = sourceStart * WORD_SIZE;
+        long startPos = sourceStart * JAVA_LONG.byteSize();
         while (bufferSlice.position() < bufferSlice.capacity()) {
             source.read(bufferSlice, startPos + bufferSlice.position());
         }
diff --git a/code/libraries/btree/src/main/java/nu/marginalia/btree/BTreeReader.java b/code/libraries/btree/src/main/java/nu/marginalia/btree/BTreeReader.java
index 778e921a..7399cf5a 100644
--- a/code/libraries/btree/src/main/java/nu/marginalia/btree/BTreeReader.java
+++ b/code/libraries/btree/src/main/java/nu/marginalia/btree/BTreeReader.java
@@ -12,7 +12,7 @@ import static java.lang.Math.min;
 public class BTreeReader {
 
     private final LongArray index;
-    private final ShiftedLongArray data;
+    private final LongArray data;
 
     public final BTreeContext ctx;
     private final BTreeHeader header;
@@ -148,7 +148,7 @@ public class BTreeReader {
         long searchStart = 0;
         for (int i = 0; i < keys.length; i++) {
             long key = keys[i];
-            searchStart = data.binarySearchN(ctx.entrySize, key, searchStart, data.size);
+            searchStart = data.binarySearchN(ctx.entrySize, key, searchStart, data.size());
             if (searchStart < 0) {
                 searchStart = LongArraySearch.decodeSearchMiss(searchStart);
             }
@@ -273,7 +273,7 @@ public class BTreeReader {
 
                     long searchEnd = dataOffset + (int) min(remainingTotal, remainingBlock);
 
-                    data.range(dataOffset, searchEnd).retainN(buffer, ctx.entrySize, boundary);
+                    data.retainN(buffer, ctx.entrySize, boundary, dataOffset, searchEnd);
                 }
             }
             else {
@@ -297,7 +297,7 @@ public class BTreeReader {
 
                     long searchEnd = dataOffset + (int) min(remainingTotal, remainingBlock);
 
-                    data.range(dataOffset, searchEnd).rejectN(buffer, ctx.entrySize, boundary);
+                    data.rejectN(buffer, ctx.entrySize, boundary, dataOffset, searchEnd);
                 }
             }
             else {
diff --git a/code/libraries/btree/src/main/java/nu/marginalia/btree/BTreeWriter.java b/code/libraries/btree/src/main/java/nu/marginalia/btree/BTreeWriter.java
index 13aca70a..c8d36c7b 100644
--- a/code/libraries/btree/src/main/java/nu/marginalia/btree/BTreeWriter.java
+++ b/code/libraries/btree/src/main/java/nu/marginalia/btree/BTreeWriter.java
@@ -41,7 +41,7 @@ public class BTreeWriter {
             throw new IllegalStateException("Dog ear was not overwritten: " + header);
         }
 
-        assert slice.isSortedN(ctx.entrySize) : "Provided data was not sorted";
+        assert slice.isSortedN(ctx.entrySize, 0, (long) numEntries * ctx.entrySize) : "Provided data was not sorted";
 
         if (header.layers() >= 1) { // Omit layer if data fits within a single block
             writeIndex(header);
@@ -56,7 +56,7 @@ public class BTreeWriter {
         map.set(offset+2, header.dataOffsetLongs());
     }
 
-    private BTreeDogEar createDogEar(BTreeContext ctx, BTreeHeader header, ShiftedLongArray slice) {
+    private BTreeDogEar createDogEar(BTreeContext ctx, BTreeHeader header, LongArray slice) {
         if (BTreeWriter.class.desiredAssertionStatus()) {
             return BTreeDogEar.create(ctx, header, slice);
         }