**Benchmark setup**

.. code-block:: python

    from pandas_vb_common import *
    
    level1 = np.array([rands(10) for _ in xrange(10)], dtype='O')
    level2 = np.array([rands(10) for _ in xrange(1000)], dtype='O')
    label1 = np.arange(10).repeat(1000)
    label2 = np.tile(np.arange(1000), 10)
    
    key1 = np.tile(level1.take(label1), 10)
    key2 = np.tile(level2.take(label2), 10)
    
    shuf = np.arange(100000)
    random.shuffle(shuf)
    try:
        index2 = MultiIndex(levels=[level1, level2], labels=[label1, label2])
        index3 = MultiIndex(levels=[np.arange(10), np.arange(100), np.arange(100)],
                            labels=[np.arange(10).repeat(10000),
                                    np.tile(np.arange(100).repeat(100), 10),
                                    np.tile(np.tile(np.arange(100), 100), 10)])
        df_multi = DataFrame(np.random.randn(len(index2), 4), index=index2,
                             columns=['A', 'B', 'C', 'D'])
    except:  # pre-MultiIndex
        pass
    
    try:
        DataFrame = DataMatrix
    except:
        pass
    
    df = DataFrame({'data1' : np.random.randn(100000),
                    'data2' : np.random.randn(100000),
                    'key1' : key1,
                    'key2' : key2})
    
    
    df_key1 = DataFrame(np.random.randn(len(level1), 4), index=level1,
                        columns=['A', 'B', 'C', 'D'])
    df_key2 = DataFrame(np.random.randn(len(level2), 4), index=level2,
                        columns=['A', 'B', 'C', 'D'])
    

**Benchmark statement**

.. code-block:: python

    df.join(df_key2, on='key2')

**Performance graph**

.. image:: vbench/figures/join_dataframe_index_single_key_bigger.png
   :width: 6in