Merge "Adding the row estimated histogram to column family" from Amnon

"This series adds the JMX API to the row estimated histogram. It adds a
 get function in the APIClient to fetch the data. The implementation is
 based on the column_family.json for the API call and on utils.json for
 the estimated histogram definition."

src/main/java/com/cloudius/urchin/api/APIClient.java

@@ -539,4 +539,19 @@ public class APIClient {
     public HistogramValues getHistogramValue(String url) {
         return getHistogramValue(url, null);
     }
+
+    public long[] getEstimatedHistogramAsLongArrValue(String string,
+            MultivaluedMap<String, String> queryParams) {
+        JsonObject obj = getJsonObj(string, queryParams);
+        JsonArray arr = obj.getJsonArray("buckets");
+        long res[] = new long[arr.size()];
+        for (int i = 0; i< arr.size(); i++) {
+            res[i] = arr.getJsonNumber(i).longValue();
+        }
+        return res;
+    }
+
+    public long[] getEstimatedHistogramAsLongArrValue(String string) {
+        return getEstimatedHistogramAsLongArrValue(string, null);
+    }
 }

src/main/java/org/apache/cassandra/db/ColumnFamilyStore.java

@@ -584,7 +584,7 @@ public class ColumnFamilyStore implements ColumnFamilyStoreMBean {
     @Deprecated
     public long[] getEstimatedRowSizeHistogram() {
         log(" getEstimatedRowSizeHistogram()");
-        return c.getLongArrValue("");
+        return c.getEstimatedHistogramAsLongArrValue("/column_family/metrics/estimated_row_size_histogram/" + getCFName());
     }
 
     /**

src/main/java/org/apache/cassandra/metrics/ColumnFamilyMetrics.java

@@ -225,7 +225,7 @@ public class ColumnFamilyMetrics {
                 factory.createMetricName("EstimatedRowSizeHistogram"),
                 new Gauge<long[]>() {
                     public long[] value() {
-                        return c.getLongArrValue("/column_family/metrics/estimated_row_size_histogram/"
+                        return c.getEstimatedHistogramAsLongArrValue("/column_family/metrics/estimated_row_size_histogram/"
                                 + cfName);
                     }
                 });
@@ -233,7 +233,7 @@ public class ColumnFamilyMetrics {
                 factory.createMetricName("EstimatedColumnCountHistogram"),
                 new Gauge<long[]>() {
                     public long[] value() {
-                        return c.getLongArrValue("/column_family/metrics/estimated_column_count_histogram/"
+                        return c.getEstimatedHistogramAsLongArrValue("/column_family/metrics/estimated_column_count_histogram/"
                                 + cfName);
                     }
                 });
@@ -252,13 +252,13 @@ public class ColumnFamilyMetrics {
                         return c.getDoubleValue("/column_family/metrics/compression_ratio/");
                     }
                 });
-        readLatency = new LatencyMetrics("/column_family/metrics/read_latency/"
-                + cfName, factory, "Read");
+        readLatency = new LatencyMetrics("/column_family/metrics/read_latency",
+                cfName, factory, "Read");
         writeLatency = new LatencyMetrics(
-                "/column_family/metrics/write_latency/" + cfName, factory,
+                "/column_family/metrics/write_latency", cfName, factory,
                 "Write");
         rangeLatency = new LatencyMetrics(
-                "/column_family/metrics/range_latency/" + cfName, factory,
+                "/column_family/metrics/range_latency", cfName, factory,
                 "Range");
         pendingFlushes = createColumnFamilyCounter(
                 "/column_family/metrics/pending_flushes", "PendingFlushes");

src/main/java/org/apache/cassandra/metrics/LatencyMetrics.java

@@ -102,6 +102,18 @@ public class LatencyMetrics {
                 factory.createMetricName(namePrefix + "TotalLatency"));
     }
 
+    public LatencyMetrics(String url, String paramName,
+            MetricNameFactory factory, String namePrefix) {
+        this.factory = factory;
+        this.namePrefix = namePrefix;
+
+        latency = APIMetrics.newTimer(url + "/histogram/" + paramName,
+                factory.createMetricName(namePrefix + "Latency"),
+                TimeUnit.MICROSECONDS, TimeUnit.SECONDS);
+        totalLatency = APIMetrics.newCounter(url + "/" + paramName,
+                factory.createMetricName(namePrefix + "TotalLatency"));
+    }
+
     /**
      * Create LatencyMetrics with given group, type, prefix to append to each
      * metric name, and scope. Any updates to this will also run on parent
@@ -130,8 +142,8 @@ public class LatencyMetrics {
     }
 
     public void release() {
-        APIMetrics.defaultRegistry().removeMetric(
-                factory.createMetricName(namePrefix + "Latency"));
+        APIMetrics.defaultRegistry()
+                .removeMetric(factory.createMetricName(namePrefix + "Latency"));
         APIMetrics.defaultRegistry().removeMetric(
                 factory.createMetricName(namePrefix + "TotalLatency"));
     }