svn commit: r1309459 - /hbase/branches/0.94/src/main/java/org/apache/hadoop/hbase/io/hfile/HFile.java

[st...@apache.org]

Author: stack
Date: Wed Apr  4 15:36:55 2012
New Revision: 1309459

URL: http://svn.apache.org/viewvc?rev=1309459&view=rev
Log:
HBASE-5706 'Dropping fs latency stats since buffer is full' spam

Modified:
    hbase/branches/0.94/src/main/java/org/apache/hadoop/hbase/io/hfile/HFile.java

Modified: hbase/branches/0.94/src/main/java/org/apache/hadoop/hbase/io/hfile/HFile.java
URL: http://svn.apache.org/viewvc/hbase/branches/0.94/src/main/java/org/apache/hadoop/hbase/io/hfile/HFile.java?rev=1309459&r1=1309458&r2=1309459&view=diff
==============================================================================
--- hbase/branches/0.94/src/main/java/org/apache/hadoop/hbase/io/hfile/HFile.java (original)
+++ hbase/branches/0.94/src/main/java/org/apache/hadoop/hbase/io/hfile/HFile.java Wed Apr  4 15:36:55 2012
@@ -192,50 +192,21 @@ public class HFile {
       new ArrayBlockingQueue<Long>(LATENCY_BUFFER_SIZE);
   private static final BlockingQueue<Long> fsPreadLatenciesNanos = 
       new ArrayBlockingQueue<Long>(LATENCY_BUFFER_SIZE);
-  private static final AtomicLong lastLoggedDataDrop = new AtomicLong(0);
-  
-  // we don't want to fill up the logs with this message, so only log it 
-  // once every 30 seconds at most
-  // I also want to avoid locks on the 'critical path' (the common case will be
-  // uncontended) - hence the CAS
-  private static void logDroppedLatencyStat() {
-    final long now = System.currentTimeMillis();      
-    final long earliestAcceptableLog = now - TimeUnit.SECONDS.toMillis(30L);
-    while (true) {
-      final long lastLog = lastLoggedDataDrop.get();
-      if (lastLog < earliestAcceptableLog) {
-        if (lastLoggedDataDrop.compareAndSet(lastLog, now)) {
-          LOG.warn("Dropping fs latency stats since buffer is full");
-          break;
-        } // otherwise (if the compaseAndSet failed) the while loop retries
-      } else {
-        break;
-      }
-    }    
-  }
   
   public static final void offerReadLatency(long latencyNanos, boolean pread) {
-    boolean stored = false;
     if (pread) {
-      stored = fsPreadLatenciesNanos.offer(latencyNanos);
+      fsPreadLatenciesNanos.offer(latencyNanos); // might be silently dropped, if the queue is full
       preadOps.incrementAndGet();
       preadTimeNano.addAndGet(latencyNanos);
     } else {
-      stored = fsReadLatenciesNanos.offer(latencyNanos);
+      fsReadLatenciesNanos.offer(latencyNanos); // might be silently dropped, if the queue is full
       readTimeNano.addAndGet(latencyNanos);
       readOps.incrementAndGet();
     }
-
-    if (!stored) { 
-      logDroppedLatencyStat();
-    }    
   }
   
   public static final void offerWriteLatency(long latencyNanos) {
-    final boolean stored = fsWriteLatenciesNanos.offer(latencyNanos);
-    if (!stored) {
-      logDroppedLatencyStat();
-    }
+    fsWriteLatenciesNanos.offer(latencyNanos); // might be silently dropped, if the queue is full
     
     writeTimeNano.addAndGet(latencyNanos);
     writeOps.incrementAndGet();