Verbatim Integer List 带来的空间开销，人们发明了Integer List Compression机制。
SIMDBP128 / SIMDPforDelta
PEF (Partitioned Elias Fano)
PFOR/PFOR Delta/ NewPforDelta Simple16 / Simple8b VB / GroupVB
* Data Structures for Inverted Indexes ([https://github.com/ot/ds2i ds2i])
* [http://github.com/ot/partitioned_elias_fano Partitioned Elias-Fano Index]