From e356d793caf2a899f23261baba922d4a08b362ed Mon Sep 17 00:00:00 2001
From: Toke Eskildsen <toke@apache.org>
Date: Mon, 3 Dec 2018 14:30:30 +0100
Subject: [PATCH] LUCENE-8374 part 4/4: Reduce reads for sparse DocValues

Offset and index jump-table for norm blocks.
---
 .../lucene/codecs/lucene70/Lucene70NormsProducer.java     | 8 ++++++--
 1 file changed, 6 insertions(+), 2 deletions(-)

diff --git a/lucene/core/src/java/org/apache/lucene/codecs/lucene70/Lucene70NormsProducer.java b/lucene/core/src/java/org/apache/lucene/codecs/lucene70/Lucene70NormsProducer.java
index c7310e848d0..321fcff6d8b 100644
--- a/lucene/core/src/java/org/apache/lucene/codecs/lucene70/Lucene70NormsProducer.java
+++ b/lucene/core/src/java/org/apache/lucene/codecs/lucene70/Lucene70NormsProducer.java
@@ -45,6 +45,7 @@ final class Lucene70NormsProducer extends NormsProducer implements Cloneable {
   private final Map<Integer,NormsEntry> norms = new HashMap<>();
   private final int maxDoc;
   private IndexInput data;
+  private final IndexedDISICacheFactory disiCacheFactory = new IndexedDISICacheFactory();
   private boolean merging;
   private Map<Integer, IndexInput> disiInputs;
   private Map<Integer, RandomAccessInput> dataInputs;
@@ -293,7 +294,9 @@ final class Lucene70NormsProducer extends NormsProducer implements Cloneable {
     } else {
       // sparse
       final IndexInput disiInput = getDisiInput(field, entry);
-      final IndexedDISI disi = new IndexedDISI(disiInput, entry.numDocsWithField);
+      final IndexedDISI disi = disiCacheFactory.createCachedIndexedDISI(
+          disiInput, entry.docsWithFieldOffset + entry.docsWithFieldLength, entry.numDocsWithField, field.name);
+
       if (entry.bytesPerNorm == 0) {
         return new SparseNormsIterator(disi) {
           @Override
@@ -342,11 +345,12 @@ final class Lucene70NormsProducer extends NormsProducer implements Cloneable {
   @Override
   public void close() throws IOException {
     data.close();
+    disiCacheFactory.releaseAll();
   }
 
   @Override
   public long ramBytesUsed() {
-    return 64L * norms.size(); // good enough
+    return 64L * norms.size() + disiCacheFactory.ramBytesUsed(); // good enough
   }
 
   @Override