diff --git a/Sources/DataSection/InMemoryDataSection.swift b/Sources/DataSection/InMemoryDataSection.swift
index 5c1d842..e6efc8a 100644
--- a/Sources/DataSection/InMemoryDataSection.swift
+++ b/Sources/DataSection/InMemoryDataSection.swift
@@ -53,7 +53,7 @@ public class InMemoryDataSection: DataSection {
   }
 
   public func lookup(pointer: Int) -> [String: Payload]? {
-    guard let payload = decoder.read(at: pointer, resolvePointers: true) else { return nil }
+    guard let payload = decoder.read(at: pointer - Int(metadata.nodeCount) - 16, resolvePointers: true) else { return nil }
     guard case let Payload.map(result) = payload else { return nil }
     return result
   }
diff --git a/Sources/IndexReader/InMemoryIndex.swift b/Sources/IndexReader/InMemoryIndex.swift
index 9389c4f..05fdbb9 100644
--- a/Sources/IndexReader/InMemoryIndex.swift
+++ b/Sources/IndexReader/InMemoryIndex.swift
@@ -4,9 +4,9 @@ import struct MetadataReader.Metadata
 public class InMemoryIndex<Pointer>: Index where Pointer: UnsignedInteger, Pointer: FixedWidthInteger {
 
   private let metadata: Metadata
-  private let tree:     [Pointer: Node<Pointer>]
+  private let tree:     Data
 
-  init(metadata: Metadata, tree: [Pointer: Node<Pointer>]) {
+  init(metadata: Metadata, tree: Data) {
     self.metadata = metadata
     self.tree = tree
   }
@@ -23,20 +23,14 @@ public class InMemoryIndex<Pointer>: Index where Pointer: UnsignedInteger, Point
     let buffer = UnsafeMutablePointer<UInt8>.allocate(capacity: searchTreeSize)
     let read   = stream.read(buffer, maxLength: searchTreeSize)
 
-    var tree: [Pointer: Node<Pointer>] = [:]
-    let nodes = Data(
+    buffer.deallocate()
+    stream.close()
+//    precondition(tree.count == metadata.nodeCount)
+    self.init(metadata: metadata, tree: Data(
       bytesNoCopy: buffer,
       count: read,
       deallocator: .none
-    )
-      .chunked(into: Int(metadata.nodeByteSize))
-      .map({ Node<Pointer>($0) })
-    for (pointer, node) in nodes.enumerated() { tree[Pointer(pointer)] = node }
-
-    buffer.deallocate()
-    stream.close()
-    precondition(tree.count == metadata.nodeCount)
-    self.init(metadata: metadata, tree: tree)
+    ))
   }
 
   public func lookup(_ ip: IpAddress) -> Pointer? {
@@ -50,9 +44,13 @@ public class InMemoryIndex<Pointer>: Index where Pointer: UnsignedInteger, Point
     }
     var pointer: Pointer = 0
 
+    let nodeByteSize = Pointer.init(metadata.nodeByteSize)
     while pointer < metadata.nodeCount {
       guard let direction = stack.popLast() else { break }
-      guard let node = tree[pointer] else { return pointer }
+      let pointerInTree = pointer * nodeByteSize
+      let nodeCandidate = tree[pointerInTree..<pointerInTree + nodeByteSize]
+      let node = Node<Pointer>(nodeCandidate)
+//      guard let node = tree[pointer] else { return pointer }
 
       switch direction {
         case .left: pointer = node.left
diff --git a/Tests/DBReaderTests/InMemoryReaderTest.swift b/Tests/DBReaderTests/InMemoryReaderTest.swift
index 4e7a527..592f867 100644
--- a/Tests/DBReaderTests/InMemoryReaderTest.swift
+++ b/Tests/DBReaderTests/InMemoryReaderTest.swift
@@ -83,7 +83,8 @@ class InMemoryReaderTest: XCTestCase {
     let factory = ReaderFactory()
     let streamFactory: () -> InputStream = {
       InputStream(
-        fileAtPath: "/Users/rocskaadam/src/adam-rocska/src/GeoIP2-swift/Tests/ApiTests/Resources/GeoLite2-City_20200526/GeoLite2-City.mmdb"
+//        fileAtPath: "/Users/rocskaadam/src/adam-rocska/src/GeoIP2-swift/Tests/ApiTests/Resources/GeoLite2-City_20200526/GeoLite2-City.mmdb"
+        fileAtPath: "/Users/rocskaadam/src/adam-rocska/src/GeoIP2-swift/Tests/ApiTests/Resources/GeoLite2-ASN_20200526/GeoLite2-ASN.mmdb"
 //        fileAtPath: "/Users/rocskaadam/src/adam-rocska/src/GeoIP2-swift/Tests/DBReaderTests/Resources/GeoLite2-Country_20200421/GeoLite2-Country.mmdb"
       )!
     }