From 2842ce30d613f69066fd46848733508fc285dd32 Mon Sep 17 00:00:00 2001
From: orbiter <orbiter@6c8d7289-2bf4-0310-a012-ef5d649a1542>
Date: Wed, 7 Sep 2011 22:15:01 +0000
Subject: [PATCH] added synchronization in ReferenceContainer and logging for
 shrinking

git-svn-id: https://svn.berlios.de/svnroot/repos/yacy/trunk@7937 6c8d7289-2bf4-0310-a012-ef5d649a1542
---
 source/net/yacy/kelondro/blob/ArrayStack.java | 22 ++++++++++-----
 .../yacy/kelondro/rwi/ReferenceContainer.java | 27 ++++++++++++-------
 2 files changed, 33 insertions(+), 16 deletions(-)

diff --git a/source/net/yacy/kelondro/blob/ArrayStack.java b/source/net/yacy/kelondro/blob/ArrayStack.java
index 047151945..bf2eb3301 100755
--- a/source/net/yacy/kelondro/blob/ArrayStack.java
+++ b/source/net/yacy/kelondro/blob/ArrayStack.java
@@ -48,6 +48,7 @@ import java.util.concurrent.ThreadPoolExecutor;
 import java.util.concurrent.TimeUnit;
 
 import net.yacy.cora.date.GenericFormatter;
+import net.yacy.cora.document.ASCII;
 import net.yacy.cora.document.UTF8;
 import net.yacy.kelondro.index.RowSpaceExceededException;
 import net.yacy.kelondro.logging.Log;
@@ -988,13 +989,14 @@ public class ArrayStack implements BLOB {
         ReferenceContainer<ReferenceType> c1, c2;
         c1 = i1.next();
         c2 = i2.next();
-        int e;
+        int e, s;
         while (true) {
             assert c1 != null;
             assert c2 != null;
             e = ordering.compare(c1.getTermHash(), c2.getTermHash());
             if (e < 0) {
-            	c1.shrinkReferences();
+            	s = c1.shrinkReferences();
+            	if (s > 0) Log.logInfo("ArrayStack", "shrinking index for " + ASCII.String(c1.getTermHash()) + " by " + s + " to " + c1.size() + " entries");
                 writer.add(c1.getTermHash(), c1.exportCollection());
                 if (i1.hasNext()) {
                     c1lh = c1.getTermHash();
@@ -1006,7 +1008,8 @@ public class ArrayStack implements BLOB {
                 break;
             }
             if (e > 0) {
-            	c2.shrinkReferences();
+                s = c2.shrinkReferences();
+                if (s > 0) Log.logInfo("ArrayStack", "shrinking index for " + ASCII.String(c2.getTermHash()) + " by " + s + " to " + c2.size() + " entries");
                 writer.add(c2.getTermHash(), c2.exportCollection());
                 if (i2.hasNext()) {
                     c2lh = c2.getTermHash();
@@ -1020,7 +1023,8 @@ public class ArrayStack implements BLOB {
             assert e == 0;
             // merge the entries
             c1 = c1.merge(c2);
-            c1.shrinkReferences();
+            s = c1.shrinkReferences();
+            if (s > 0) Log.logInfo("ArrayStack", "shrinking index for " + ASCII.String(c1.getTermHash()) + " by " + s + " to " + c1.size() + " entries");
             writer.add(c1.getTermHash(), c1.exportCollection());
             c1lh = c1.getTermHash();
             c2lh = c2.getTermHash();
@@ -1049,7 +1053,8 @@ public class ArrayStack implements BLOB {
         assert (c1 == null) || (c2 == null);
         while (c1 != null) {
             //System.out.println("FLUSH REMAINING 1: " + c1.getWordHash());
-        	c1.shrinkReferences();
+            s = c1.shrinkReferences();
+            if (s > 0) Log.logInfo("ArrayStack", "shrinking index for " + ASCII.String(c1.getTermHash()) + " by " + s + " to " + c1.size() + " entries");
             writer.add(c1.getTermHash(), c1.exportCollection());
             if (i1.hasNext()) {
                 c1lh = c1.getTermHash();
@@ -1061,7 +1066,8 @@ public class ArrayStack implements BLOB {
         }
         while (c2 != null) {
             //System.out.println("FLUSH REMAINING 2: " + c2.getWordHash());
-        	c2.shrinkReferences();
+            s = c2.shrinkReferences();
+            if (s > 0) Log.logInfo("ArrayStack", "shrinking index for " + ASCII.String(c2.getTermHash()) + " by " + s + " to " + c2.size() + " entries");
             writer.add(c2.getTermHash(), c2.exportCollection());
             if (i2.hasNext()) {
                 c2lh = c2.getTermHash();
@@ -1081,9 +1087,11 @@ public class ArrayStack implements BLOB {
         byte[] clh;
         ReferenceContainer<ReferenceType> c;
         c = i.next();
+        int s;
         while (true) {
             assert c != null;
-            c.shrinkReferences();
+            s = c.shrinkReferences();
+            if (s > 0) Log.logInfo("ArrayStack", "shrinking index for " + ASCII.String(c.getTermHash()) + " by " + s + " to " + c.size() + " entries");
             writer.add(c.getTermHash(), c.exportCollection());
             if (i.hasNext()) {
                 clh = c.getTermHash();
diff --git a/source/net/yacy/kelondro/rwi/ReferenceContainer.java b/source/net/yacy/kelondro/rwi/ReferenceContainer.java
index d97bb67c6..5227a0288 100644
--- a/source/net/yacy/kelondro/rwi/ReferenceContainer.java
+++ b/source/net/yacy/kelondro/rwi/ReferenceContainer.java
@@ -190,16 +190,25 @@ public class ReferenceContainer<ReferenceType extends Reference> extends RowSet
         return count;
     }
 
-    public void shrinkReferences() {
-    	final int diff = size() - maxReferences;
-    	if (maxReferences <= 0 || diff <= 0) return;
-    	final int[] indexes = oldPostions(diff);
-    	Arrays.sort(indexes);
-    	for (int i = indexes.length - 1; i >= 0; i--) {
-    		if (indexes[i] < 0) break;
-    		removeRow(indexes[i], false);
+    /**
+     * Shrink the reference size in such a way that it does not exceed maxReferences
+     * In case that the index is too large, old entries are deleted
+     * @return the number of deleted entries
+     */
+    public int shrinkReferences() {
+        final int oldsize = size();
+    	final int diff = oldsize - maxReferences;
+    	if (maxReferences <= 0 || diff <= 0) return 0;
+    	synchronized (this) {
+        	final int[] indexes = oldPostions(diff);
+        	Arrays.sort(indexes);
+        	for (int i = indexes.length - 1; i >= 0; i--) {
+        		if (indexes[i] < 0) break;
+        		removeRow(indexes[i], false);
+        	}
+        	sort();
     	}
-    	sort();
+    	return oldsize - size();
     }
 
     private int[] oldPostions(final int count) {