From 3d7bcd020e03ca89dccab18dd87cde453beeeafa Mon Sep 17 00:00:00 2001
From: chenheng <chenheng@apache.org>
Date: Wed, 17 Aug 2016 11:06:34 +0800
Subject: [PATCH] HBASE-15635 Mean age of Blocks in cache (seconds) on webUI
 should be greater than zero

Signed-off-by: stack <stack@apache.org>
---
 .../hadoop/hbase/tmpl/regionserver/BlockCacheTmpl.jamon     | 6 +-----
 .../org/apache/hadoop/hbase/io/hfile/BlockCacheUtil.java    | 6 +++++-
 .../java/org/apache/hadoop/hbase/io/hfile/CacheStats.java   | 4 +++-
 3 files changed, 9 insertions(+), 7 deletions(-)

diff --git a/hbase-server/src/main/jamon/org/apache/hadoop/hbase/tmpl/regionserver/BlockCacheTmpl.jamon b/hbase-server/src/main/jamon/org/apache/hadoop/hbase/tmpl/regionserver/BlockCacheTmpl.jamon
index 49a1e1bef8b..daa5d76877e 100644
--- a/hbase-server/src/main/jamon/org/apache/hadoop/hbase/tmpl/regionserver/BlockCacheTmpl.jamon
+++ b/hbase-server/src/main/jamon/org/apache/hadoop/hbase/tmpl/regionserver/BlockCacheTmpl.jamon
@@ -177,7 +177,6 @@ org.apache.hadoop.util.StringUtils.TraditionalBinaryPrefix;
 <%java>
   AgeSnapshot ageAtEvictionSnapshot = bc.getStats().getAgeAtEvictionSnapshot();
   // Only show if non-zero mean and stddev as is the case in combinedblockcache
-  double mean = ageAtEvictionSnapshot.getMean();
 </%java>
     <tr>
         <td>Evicted</td>
@@ -189,13 +188,11 @@ org.apache.hadoop.util.StringUtils.TraditionalBinaryPrefix;
         <td><% String.format("%,d", bc.getStats().getEvictionCount()) %></td>
         <td>The total number of times an eviction has occurred</td>
     </tr>
-<%if mean > 0 %>
     <tr>
         <td>Mean</td>
-        <td><% String.format("%,d", (long)(ageAtEvictionSnapshot.getMean()/(1000000 * 1000))) %></td>
+        <td><% String.format("%,d", (long)ageAtEvictionSnapshot.getMean()) %></td>
         <td>Mean age of Blocks at eviction time (seconds)</td>
     </tr>
-</%if>
 </%def>
 
 <%def hits_tmpl>
@@ -288,7 +285,6 @@ are combined counts. Request count is sum of hits and misses.</p>
     boolean evictions;
 </%args>
 <%java>
-  final long nanosPerSecond = 1000000000;
   String bcUrl = "http://hbase.apache.org/devapidocs/" + bc.getClass().getName().replaceAll("\\.", "/") + ".html";
   String bcName = bc.getClass().getSimpleName();
   org.apache.hadoop.hbase.io.hfile.BlockCacheUtil.CachedBlocksByFile cbsbf =
diff --git a/hbase-server/src/main/java/org/apache/hadoop/hbase/io/hfile/BlockCacheUtil.java b/hbase-server/src/main/java/org/apache/hadoop/hbase/io/hfile/BlockCacheUtil.java
index 89f73eb1367..d868a1af42f 100644
--- a/hbase-server/src/main/java/org/apache/hadoop/hbase/io/hfile/BlockCacheUtil.java
+++ b/hbase-server/src/main/java/org/apache/hadoop/hbase/io/hfile/BlockCacheUtil.java
@@ -38,6 +38,10 @@ import org.codehaus.jackson.map.SerializationConfig;
  */
 @InterfaceAudience.Private
 public class BlockCacheUtil {
+
+
+  public static final long NANOS_PER_SECOND = 1000000000;
+
   /**
    * Needed generating JSON.
    */
@@ -223,7 +227,7 @@ public class BlockCacheUtil {
         this.dataBlockCount++;
         this.dataSize += cb.getSize();
       }
-      long age = this.now - cb.getCachedTime();
+      long age = (this.now - cb.getCachedTime())/NANOS_PER_SECOND;
       this.hist.add(age, 1);
       return false;
     }
diff --git a/hbase-server/src/main/java/org/apache/hadoop/hbase/io/hfile/CacheStats.java b/hbase-server/src/main/java/org/apache/hadoop/hbase/io/hfile/CacheStats.java
index 298dcf7cde9..f38ec70eec0 100644
--- a/hbase-server/src/main/java/org/apache/hadoop/hbase/io/hfile/CacheStats.java
+++ b/hbase-server/src/main/java/org/apache/hadoop/hbase/io/hfile/CacheStats.java
@@ -247,7 +247,9 @@ public class CacheStats {
   }
 
   public void evicted(final long t, boolean primary) {
-    if (t > this.startTime) this.ageAtEviction.add(t - this.startTime,1);
+    if (t > this.startTime) {
+      this.ageAtEviction.add((t - this.startTime) / BlockCacheUtil.NANOS_PER_SECOND, 1);
+    }
     this.evictedBlockCount.increment();
     if (primary) {
       primaryEvictedBlockCount.increment();