org.forstdb.MemoryUtil Maven / Gradle / Ivy

Go to download

Show more of this group Show more artifacts with this name
Show all versions of forstjni Show documentation

ForSt fat jar with modifications specific for Apache Flink that contains .so files for linux32 and linux64 (glibc and musl-libc), jnilib files for Mac OSX, and a .dll for Windows x64.

The newest version!

// Copyright (c) 2011-present, Facebook, Inc.  All rights reserved.
//  This source code is licensed under both the GPLv2 (found in the
//  COPYING file in the root directory) and Apache 2.0 License
//  (found in the LICENSE.Apache file in the root directory).

package org.forstdb;

import java.util.*;

/**
 * JNI passthrough for MemoryUtil.
 */
public class MemoryUtil {

  /**
   * Returns the approximate memory usage of different types in the input
   * list of DBs and Cache set.  For instance, in the output map the key
   * kMemTableTotal will be associated with the memory
   * usage of all the mem-tables from all the input rocksdb instances.
   *
   * Note that for memory usage inside Cache class, we will
   * only report the usage of the input "cache_set" without
   * including those Cache usage inside the input list "dbs"
   * of DBs.
   *
   * @param dbs List of dbs to collect memory usage for.
   * @param caches Set of caches to collect memory usage for.
   * @return Map from {@link MemoryUsageType} to memory usage as a {@link Long}.
   */
  @SuppressWarnings("PMD.CloseResource")
  public static Map getApproximateMemoryUsageByType(
      final List dbs, final Set caches) {
    final int dbCount = (dbs == null) ? 0 : dbs.size();
    final int cacheCount = (caches == null) ? 0 : caches.size();
    final long[] dbHandles = new long[dbCount];
    final long[] cacheHandles = new long[cacheCount];
    if (dbCount > 0) {
      final ListIterator dbIter = dbs.listIterator();
      while (dbIter.hasNext()) {
        dbHandles[dbIter.nextIndex()] = dbIter.next().nativeHandle_;
      }
    }
    if (cacheCount > 0) {
      // NOTE: This index handling is super ugly but I couldn't get a clean way to track both the
      // index and the iterator simultaneously within a Set.
      int i = 0;
      for (final Cache cache : caches) {
        cacheHandles[i] = cache.nativeHandle_;
        i++;
      }
    }
    final Map byteOutput = getApproximateMemoryUsageByType(dbHandles, cacheHandles);
    final Map output = new HashMap<>();
    for (final Map.Entry longEntry : byteOutput.entrySet()) {
      output.put(MemoryUsageType.getMemoryUsageType(longEntry.getKey()), longEntry.getValue());
    }
    return output;
  }

  private static native Map getApproximateMemoryUsageByType(
      final long[] dbHandles, final long[] cacheHandles);
}