add cache errorCount

client/src/main/java/com/metamx/druid/client/cache/CacheMonitor.java

@@ -67,5 +67,6 @@ public class CacheMonitor extends AbstractMonitor
     emitter.emit(builder.build(String.format("%s/hitRate", metricPrefix), cacheStats.hitRate()));
     emitter.emit(builder.build(String.format("%s/averageBytes", metricPrefix), cacheStats.averageBytes()));
     emitter.emit(builder.build(String.format("%s/timeouts", metricPrefix), cacheStats.getNumTimeouts()));
+    emitter.emit(builder.build(String.format("%s/errors", metricPrefix), cacheStats.getNumErrors()));
   }
 }

client/src/main/java/com/metamx/druid/client/cache/CacheStats.java

@@ -29,6 +29,7 @@ public class CacheStats
   private final long sizeInBytes;
   private final long numEvictions;
   private final long numTimeouts;
+  private final long numErrors;
 
   public CacheStats(
       long numHits,
@@ -36,7 +37,8 @@ public class CacheStats
       long size,
       long sizeInBytes,
       long numEvictions,
-      long numTimeouts
+      long numTimeouts,
+      long numErrors
   )
   {
     this.numHits = numHits;
@@ -45,6 +47,7 @@ public class CacheStats
     this.sizeInBytes = sizeInBytes;
     this.numEvictions = numEvictions;
     this.numTimeouts = numTimeouts;
+    this.numErrors = numErrors;
   }
 
   public long getNumHits()
@@ -77,6 +80,11 @@ public class CacheStats
     return numTimeouts;
   }
 
+  public long getNumErrors()
+  {
+    return numErrors;
+  }
+
   public long numLookups()
   {
     return numHits + numMisses;
@@ -104,7 +112,8 @@ public class CacheStats
         size - oldStats.size,
         sizeInBytes - oldStats.sizeInBytes,
         numEvictions - oldStats.numEvictions,
-        numTimeouts - oldStats.numTimeouts
+        numTimeouts - oldStats.numTimeouts,
+        numErrors - oldStats.numErrors
     );
   }
 }

client/src/main/java/com/metamx/druid/client/cache/MapCache.java

@@ -76,6 +76,7 @@ public class MapCache implements Cache
         byteCountingLRUMap.size(),
         byteCountingLRUMap.getNumBytes(),
         byteCountingLRUMap.getEvictionCount(),
+        0,
         0
     );
   }

client/src/main/java/com/metamx/druid/client/cache/MemcachedCache.java

@@ -91,6 +91,7 @@ public class MemcachedCache implements Cache
   private final AtomicLong hitCount = new AtomicLong(0);
   private final AtomicLong missCount = new AtomicLong(0);
   private final AtomicLong timeoutCount = new AtomicLong(0);
+  private final AtomicLong errorCount = new AtomicLong(0);
 
   MemcachedCache(MemcachedClientIF client, String memcachedPrefix, int timeout, int expiration) {
     Preconditions.checkArgument(memcachedPrefix.length() <= MAX_PREFIX_LENGTH,
@@ -112,7 +113,8 @@ public class MemcachedCache implements Cache
         0,
         0,
         0,
-        timeoutCount.get()
+        timeoutCount.get(),
+        errorCount.get()
     );
   }
 
@@ -124,6 +126,7 @@ public class MemcachedCache implements Cache
       future = client.asyncGet(computeKeyHash(memcachedPrefix, key));
     } catch(IllegalStateException e) {
       // operation did not get queued in time (queue is full)
+      errorCount.incrementAndGet();
       log.warn(e, "Unable to queue cache operation");
       return null;
     }
@@ -147,6 +150,7 @@ public class MemcachedCache implements Cache
       throw Throwables.propagate(e);
     }
     catch(ExecutionException e) {
+      errorCount.incrementAndGet();
       log.warn(e, "Exception pulling item from cache");
       return null;
     }
@@ -159,6 +163,7 @@ public class MemcachedCache implements Cache
       client.set(computeKeyHash(memcachedPrefix, key), expiration, serializeValue(key, value));
     } catch(IllegalStateException e) {
       // operation did not get queued in time (queue is full)
+      errorCount.incrementAndGet();
       log.warn(e, "Unable to queue cache operation");
     }
   }
@@ -209,8 +214,8 @@ public class MemcachedCache implements Cache
     try {
       future = client.asyncGetBulk(keyLookup.keySet());
     } catch(IllegalStateException e) {
-      timeoutCount.incrementAndGet();
       // operation did not get queued in time (queue is full)
+      errorCount.incrementAndGet();
       log.warn(e, "Unable to queue cache operation");
       return results;
     }
@@ -241,6 +246,7 @@ public class MemcachedCache implements Cache
       throw Throwables.propagate(e);
     }
     catch(ExecutionException e) {
+      errorCount.incrementAndGet();
       log.warn(e, "Exception pulling item from cache");
       return results;
     }