This documentation was dangerous because it felt like it was possible to gain
substantial performance by just switching the codec of the index.
However, non-default codecs are dangerous to use since they are not supported
in terms of backward compatibility, and most improvements that they bring have
been folded into the default codec anyway (for example, the default codec
"pulses" postings lists that contain a single document).
Adrien Grand
Clinton Gormley
Simon Willnauer
Lee Hinman