title: Retrieve Records faster from whole dask dataframe
body: <p>I have csv file with 109 Million records. So, I'm using dask to load the dataset in python. And I want to get record with one condition.</p>
  <pre><code>import dask.dataframe as dd
  
  df = dd.read_csv(file)
  df[df[column] ==  'ABC'].head()
  </code></pre>
  <p>Now even though the value is present in the file it's not returning anything and I figured out it's because it has loaded in 400 partitions and it's just finding in the last partion, so I mentioned <code>blocksize=None</code> while reading the file so I'll get just one block as whole.</p>
  <pre><code>df = dd.read_csv(file, blocksize=None)
  </code></pre>
  <p>And now when I'm trying to look for the record it's running out of memory, any way where I can look for record in whole dataframe? or how can I look for record in whole df after partioning.</p>