It is clearly stated in the article:<p><pre><code>  When Google published the Dremel paper in 2010, it explained how this structure is preserved within column store.
  ...
  The definition and repetition levels encoding is so efficient for semistructured data that other open source columnar formats, such as Parquet, also adopted this technique.
</code></pre>
Parquet is an open-source reimplementation of the columnar storage format described in Google&#x27;s 2010 Dremel paper. Capacitor is Google&#x27;s next-generation columnar storage format.