OPENDJ-2631: OOME error while importing 100M entries.

Yannick Lecaillez

25.20.2016 b326ec684b78ad80beb7600da95c5bf29e58900b

 opendj-server-legacy/src/main/java/org/opends/server/backends/pluggable/OnDiskMergeImporter.java

@@ -1825,20 +1825,14 @@
         */
        mmapBuffer.force();
        mmapBuffer = null;
        try
        {
          return new FileRegionChunkCursor(channel.map(MapMode.READ_ONLY, startOffset, size));
        }
        catch (IOException e)
        {
          throw new StorageRuntimeException(e);
        }
        return new FileRegionChunkCursor(startOffset, size);
      }

      /** Cursor through the specific memory-mapped file's region. */
      private final class FileRegionChunkCursor implements MeteredCursor<ByteString, ByteString>
      {
        private final ByteBuffer region;
        private final long regionOffset;
        private final long regionSize;
        private final InputStream asInputStream = new InputStream()
        {
          @Override
@@ -1847,16 +1841,19 @@
            return region.get() & 0xFF;
          }
        };
        private ByteBuffer region;
        private ByteString key, value;

        FileRegionChunkCursor(MappedByteBuffer data)
        FileRegionChunkCursor(long regionOffset, long regionSize)
        {
          this.region = data;
          this.regionOffset = regionOffset;
          this.regionSize = regionSize;
        }

        @Override
        public boolean next()
        {
          ensureRegionIsMemoryMapped();
          if (!region.hasRemaining())
          {
            key = value = null;
@@ -1885,6 +1882,22 @@
          return true;
        }

        private void ensureRegionIsMemoryMapped()
        {
          if (region == null)
          {
            // Because mmap() regions are a counted and limited resources, we create them lazily.
            try
            {
              region = channel.map(MapMode.READ_ONLY, regionOffset, regionSize);
            }
            catch (IOException e)
            {
              throw new IllegalStateException(e);
            }
          }
        }

        @Override
        public boolean isDefined()
        {
@@ -1915,6 +1928,7 @@
        public void close()
        {
          key = value = null;
          region = null;
        }

        @Override
@@ -1926,13 +1940,13 @@
        @Override
        public long getNbBytesRead()
        {
          return region.position();
          return region == null ? 0 : region.position();
        }

        @Override
        public long getNbBytesTotal()
        {
          return region.limit();
          return regionSize;
        }
      }
    }