From ea37b9ae870257c943bdc8c2896f1238a4dc94b6 Mon Sep 17 00:00:00 2001
From: Uwe Schindler <uschindler@apache.org>
Date: Sat, 25 Feb 2017 21:15:09 +0100
Subject: [PATCH] SOLR-10158: Add support for "preload" option in
 MMapDirectoryFactory

---
 solr/CHANGES.txt                                              | 3 +++
 .../src/java/org/apache/solr/core/MMapDirectoryFactory.java   | 4 ++++
 2 files changed, 7 insertions(+)

diff --git a/solr/CHANGES.txt b/solr/CHANGES.txt
index 2b0044c3f6e..e06603cb38e 100644
--- a/solr/CHANGES.txt
+++ b/solr/CHANGES.txt
@@ -134,6 +134,9 @@ New Features
   field must both be stored=false, indexed=false, docValues=true. (Ishan Chattopadhyaya, hossman, noble,
   shalin, yonik)
 
+* SOLR-10158: Add support for "preload" option in MMapDirectoryFactory.
+  (Amrit Sarkar via Uwe Schindler)
+
 Bug Fixes
 ----------------------
 
diff --git a/solr/core/src/java/org/apache/solr/core/MMapDirectoryFactory.java b/solr/core/src/java/org/apache/solr/core/MMapDirectoryFactory.java
index c68ae62cf0e..e9fbce70619 100644
--- a/solr/core/src/java/org/apache/solr/core/MMapDirectoryFactory.java
+++ b/solr/core/src/java/org/apache/solr/core/MMapDirectoryFactory.java
@@ -35,6 +35,7 @@ import org.slf4j.LoggerFactory;
  * Can set the following parameters:
  * <ul>
  *  <li>unmap -- See {@link MMapDirectory#setUseUnmap(boolean)}</li>
+ *  <li>preload -- See {@link MMapDirectory#setPreload(boolean)}</li>
  *  <li>maxChunkSize -- The Max chunk size.  See {@link MMapDirectory#MMapDirectory(Path, LockFactory, int)}</li>
  * </ul>
  *
@@ -42,6 +43,7 @@ import org.slf4j.LoggerFactory;
 public class MMapDirectoryFactory extends StandardDirectoryFactory {
   private static final Logger log = LoggerFactory.getLogger(MethodHandles.lookup().lookupClass());
   boolean unmapHack;
+  boolean preload;
   private int maxChunk;
 
   @Override
@@ -53,6 +55,7 @@ public class MMapDirectoryFactory extends StandardDirectoryFactory {
       throw new IllegalArgumentException("maxChunk must be greater than 0");
     }
     unmapHack = params.getBool("unmap", true);
+    preload = params.getBool("preload", false); //default turn-off
   }
 
   @Override
@@ -64,6 +67,7 @@ public class MMapDirectoryFactory extends StandardDirectoryFactory {
     } catch (IllegalArgumentException e) {
       log.warn("Unmap not supported on this JVM, continuing on without setting unmap", e);
     }
+    mapDirectory.setPreload(preload);
     return mapDirectory;
   }