@Override
  public long getEstimatedMemorySize() {
    JavaDataModel jdm = JavaDataModel.get();
    long size = 0;
    size += writeBuffers == null ? 0 : jdm.arrayList() + (writeBuffers.size() * jdm.lengthForByteArrayOfSize(wbSize));
    size += (3 * jdm.primitive2());
    size += writePos == null ? 0 : writePos.getEstimatedMemorySize();
    size += unsafeReadPos == null ? 0 : unsafeReadPos.getEstimatedMemorySize();
    return size;
  }
Write buffer size
@return write buffer size
serde/src/java/org/apache/hadoop/hive/serde2/WriteBuffers.java