Add histogramType for statistics

Author: Ankit Gupta

Makefile

@@ -420,7 +420,7 @@ ldb: tools/ldb.o $(LIBOBJECTS)
 # ---------------------------------------------------------------------------
 # Jni stuff
 # ---------------------------------------------------------------------------
-JNI_NATIVE_SOURCES = ./java/rocksjni/rocksjni.cc ./java/rocksjni/options.cc ./java/rocksjni/write_batch.cc
+JNI_NATIVE_SOURCES = ./java/rocksjni/rocksjni.cc ./java/rocksjni/options.cc ./java/rocksjni/write_batch.cc ./java/rocksjni/statistics.cc
 
 JAVA_INCLUDE = -I/usr/lib/jvm/java-openjdk/include/ -I/usr/lib/jvm/java-openjdk/include/linux
 ROCKSDBJNILIB = ./java/librocksdbjni.so

java/Makefile

@@ -16,7 +16,7 @@ sample: java
 	javac -cp $(ROCKSDB_JAR) RocksDBSample.java
 	@rm -rf /tmp/rocksdbjni
 	@rm -rf /tmp/rocksdbjni_not_found
-	java -ea -Djava.library.path=.:../ -cp ".:./*" RocksDBSample /tmp/rocksdbjni
+	java -ea -Djava.library.path=.:../ -cp ".:./*" -Xcheck:jni RocksDBSample /tmp/rocksdbjni
 	@rm -rf /tmp/rocksdbjni
 	@rm -rf /tmp/rocksdbjni_not_found
 

java/RocksDBSample.java

@@ -40,7 +40,7 @@ public static void main(String[] args) {
         .setDisableSeekCompaction(true)
         .setBlockSize(64 * SizeUnit.KB)
         .setMaxBackgroundCompactions(10);
-    Statistics stats = new Statistics(options.statisticsPtr());
+    Statistics stats = options.statisticsPtr();
 
     assert(options.createIfMissing() == true);
     assert(options.writeBufferSize() == 8 * SizeUnit.KB);
@@ -124,16 +124,24 @@ public static void main(String[] args) {
       writeOpts.dispose();
 
       try {
-        for(TickerType statsType : TickerType.values()) {
+        for (TickerType statsType : TickerType.values()) {
           stats.getTickerCount(statsType);
         }
         System.out.println("getTickerCount() passed.");
-      }
-      catch(Exception e) {
+      } catch (Exception e) {
         System.out.println("Failed in call to getTickerCount()");
         assert(false); //Should never reach here.
       }
-
+      
+      try {
+        for (HistogramType histogramType : HistogramType.values()) {
+          HistogramData data = stats.geHistogramData(histogramType);
+        }
+        System.out.println("geHistogramData() passed.");
+      } catch (Exception e) {
+        System.out.println("Failed in call to geHistogramData()");
+        assert(false); //Should never reach here.
+      }
     } catch (RocksDBException e) {
       System.err.println(e);
     }

java/org/rocksdb/Options.java

@@ -220,13 +220,16 @@ public Options createStatistics() {
    *
    * @see createStatistics()
    */
-  public long statisticsPtr() {
+  public Statistics statisticsPtr() {
     assert(isInitialized());
 
     long statsPtr = statisticsPtr(nativeHandle_);
-    assert(statsPtr != 0);
+    if(statsPtr == 0) {
+      createStatistics();
+      statsPtr = statisticsPtr(nativeHandle_);
+    }
 
-    return statsPtr;
+    return new Statistics(statsPtr);
   }
 
   /**

java/org/rocksdb/Statistics.java

@@ -11,7 +11,7 @@
  */
 public class Statistics {
 
-  private long statsHandle_;
+  private final long statsHandle_;
 
   public Statistics(long statsHandle) {
     statsHandle_ = statsHandle;
@@ -22,9 +22,16 @@ public long getTickerCount(TickerType tickerType) {
     return getTickerCount0(tickerType.getValue(), statsHandle_);
   }
 
+  public HistogramData geHistogramData(HistogramType histogramType) {
+    assert(isInitialized());
+    HistogramData hist = geHistogramData0(histogramType.getValue(), statsHandle_);
+    return hist;
+  }
+  
   private boolean isInitialized() {
     return (statsHandle_ != 0);
   }
 
-  private native long getTickerCount0(int ticker, long handle);
+  private native long getTickerCount0(int tickerType, long handle);
+  private native HistogramData geHistogramData0(int histogramType, long handle);
 }

java/rocksjni/portal.h

@@ -170,5 +170,15 @@ class WriteBatchJni {
         reinterpret_cast<jlong>(wb));
   }
 };
+
+class HistogramDataJni {
+ public:
+  static jmethodID getConstructorMethodId(JNIEnv* env, jclass jclazz) {
+    static jmethodID mid = env->GetMethodID(
+        jclazz, "<init>", "(DDDDD)V");
+    assert(mid != nullptr);
+    return mid;
+  }
+};
 }  // namespace rocksdb
 #endif  // JAVA_ROCKSJNI_PORTAL_H_

java/rocksjni/statistics.cc

@@ -13,16 +13,34 @@
 #include "include/org_rocksdb_Statistics.h"
 #include "rocksjni/portal.h"
 #include "rocksdb/statistics.h"
+#include <iostream>
 
 /*
  * Class:     org_rocksdb_Statistics
  * Method:    getTickerCount0
  * Signature: (IJ)J
  */
 jlong Java_org_rocksdb_Statistics_getTickerCount0(
-    JNIEnv* env, jobject jobj, int ticker, jlong handle) {
+    JNIEnv* env, jobject jobj, int tickerType, jlong handle) {
   auto st = reinterpret_cast<rocksdb::Statistics*>(handle);
   assert(st != nullptr);
 
-  return st->getTickerCount(static_cast<rocksdb::Tickers>(ticker));
+  return st->getTickerCount(static_cast<rocksdb::Tickers>(tickerType));
+}
+
+jobject Java_org_rocksdb_Statistics_geHistogramData0(
+  JNIEnv* env, jobject jobj, int histogramType, jlong handle) {
+  auto st = reinterpret_cast<rocksdb::Statistics*>(handle);
+  assert(st != nullptr);
+  
+  rocksdb::HistogramData data;
+  st->histogramData(static_cast<rocksdb::Histograms>(histogramType),
+    &data);
+  
+  // Don't reuse class pointer
+  jclass jclazz = env->FindClass("org/rocksdb/HistogramData");
+  jmethodID mid = rocksdb::HistogramDataJni::getConstructorMethodId(
+      env, jclazz);
+  return env->NewObject(jclazz, mid, data.median, data.percentile95,
+      data.percentile99, data.average, data.standard_deviation);
 }