From 0933faf06b277a548d1a190c39b5932399b3274b Mon Sep 17 00:00:00 2001
From: Michael McCandless <mikemccand@apache.org>
Date: Mon, 8 Oct 2012 17:41:15 +0000
Subject: [PATCH] make MockRandomMergePolicy a bit smarter

git-svn-id: https://svn.apache.org/repos/asf/lucene/dev/trunk@1395689 13f79535-47bb-0310-9956-ffa450edef68
---
 .../org/apache/lucene/index/IndexWriter.java  |  6 +++++
 .../lucene/index/MockRandomMergePolicy.java   | 23 +++++++++++++++----
 2 files changed, 24 insertions(+), 5 deletions(-)

diff --git a/lucene/core/src/java/org/apache/lucene/index/IndexWriter.java b/lucene/core/src/java/org/apache/lucene/index/IndexWriter.java
index 0d515a56772..0ba15db616d 100644
--- a/lucene/core/src/java/org/apache/lucene/index/IndexWriter.java
+++ b/lucene/core/src/java/org/apache/lucene/index/IndexWriter.java
@@ -3367,9 +3367,15 @@ public class IndexWriter implements Closeable, TwoPhaseCommit {
     boolean isExternal = false;
     for(SegmentInfoPerCommit info : merge.segments) {
       if (mergingSegments.contains(info)) {
+        if (infoStream.isEnabled("IW")) {
+          infoStream.message("IW", "reject merge " + segString(merge.segments) + ": segment " + segString(info) + " is already marked for merge");
+        }
         return false;
       }
       if (!segmentInfos.contains(info)) {
+        if (infoStream.isEnabled("IW")) {
+          infoStream.message("IW", "reject merge " + segString(merge.segments) + ": segment " + segString(info) + " does not exist in live infos");
+        }
         return false;
       }
       if (info.info.dir != directory) {
diff --git a/lucene/test-framework/src/java/org/apache/lucene/index/MockRandomMergePolicy.java b/lucene/test-framework/src/java/org/apache/lucene/index/MockRandomMergePolicy.java
index 1890501eae7..fb55f76e37f 100644
--- a/lucene/test-framework/src/java/org/apache/lucene/index/MockRandomMergePolicy.java
+++ b/lucene/test-framework/src/java/org/apache/lucene/index/MockRandomMergePolicy.java
@@ -19,10 +19,11 @@ package org.apache.lucene.index;
 
 import java.io.IOException;
 import java.util.ArrayList;
+import java.util.Collection;
 import java.util.Collections;
 import java.util.List;
-import java.util.Random;
 import java.util.Map;
+import java.util.Random;
 
 import org.apache.lucene.util._TestUtil;
 
@@ -43,14 +44,26 @@ public class MockRandomMergePolicy extends MergePolicy {
     MergeSpecification mergeSpec = null;
     //System.out.println("MRMP: findMerges sis=" + segmentInfos);
 
-    if (segmentInfos.size() > 1 && random.nextInt(5) == 3) {
-      
-      List<SegmentInfoPerCommit> segments = new ArrayList<SegmentInfoPerCommit>(segmentInfos.asList());
+    int numSegments = segmentInfos.size();
+
+    List<SegmentInfoPerCommit> segments = new ArrayList<SegmentInfoPerCommit>();
+    final Collection<SegmentInfoPerCommit> merging = writer.get().getMergingSegments();
+
+    for(SegmentInfoPerCommit sipc : segmentInfos) {
+      if (!merging.contains(sipc)) {
+        segments.add(sipc);
+      }
+    }
+
+    numSegments = segments.size();
+
+    if (numSegments > 1 && (numSegments > 30 || random.nextInt(5) == 3)) {
+
       Collections.shuffle(segments, random);
 
       // TODO: sometimes make more than 1 merge?
       mergeSpec = new MergeSpecification();
-      final int segsToMerge = _TestUtil.nextInt(random, 1, segmentInfos.size());
+      final int segsToMerge = _TestUtil.nextInt(random, 1, numSegments);
       mergeSpec.add(new OneMerge(segments.subList(0, segsToMerge)));
     }