protected void setWriteBlockAsReadBlock() {
    this.itrCursor = 0;
    this.readBlockSize = this.addCursor;
    this.firstReadBlockPointer = this.currentReadBlock;
    currentReadBlock = currentWriteBlock;
  }
Remove all elements in the RowContainer.
ql/src/java/org/apache/hadoop/hive/ql/exec/persistence/RowContainer.java