Lucene (and therefore Elasticsearch and Solar) uses bitmaps for its filter cache. https://www.elastic.co/blog/frame-of-reference-and-roaring-bitmaps https://ww

Lucene (and therefore Elasticsearch and Solar) uses bitmaps for its filter cache. https://www.elastic.co/blog/frame-of-reference-and-roaring-bitmaps https://www.elastic.co/blog/frame-of-reference-and-roaring-b... ClickHouse has some bitmap functions as well though not for indices. https://clickhouse.com/docs/en/sql-reference/functions/bitmap-functions/ https://clickhouse.com/docs/en/sql-reference/functions/bitma... I don't think they're unknown to most db developers, just not the best fit for a common query loads. You can scan through a bitmap really fast yes, but you can also read a list of document IDs from a BTree very quickly for any specific value. Would like to see some benchmarks of this database for comparison.