Postings listsWhile it may surprise you if you are new to search engine internals, one of the most important building blocks of a search engine is the ability to efficiently compress and quickly decode sorted lists of integers. Why is this useful? As you may know, Elasticsearch shards, which are Lucene indices under the hood, split the data that they store into segments which are regularly merged
![Frame of Reference and Roaring Bitmaps](https://cdn-ak-scissors.b.st-hatena.com/image/square/920e019aaec2913305595d3953ac79066eeffb34/height=288;version=1;width=512/https%3A%2F%2Fwww.elastic.co%2Fstatic-res%2Fimages%2Fsocial_media_default.png)