Constructing Concurrent Inverted Indexes in Go

Tue, 16 Jun 2026 22:00:00 +0530

I spent a Saturday afternoon benchmarking a concurrent inverted index and discovered that a single sync.RWMutex starts to break down at roughly 4 concurrent readers. The degradation is not linear. It is not graceful. It is a cliff.

The inverted index is one of the oldest data structures in information retrieval. It maps terms to the documents that contain them, forming the backbone of every search engine from Elasticsearch to Lucene to Google’s earliest prototypes. The data structure itself is simple. Making it fast under concurrent load is not.

Data-Structures on Lorbic

Constructing Concurrent Inverted Indexes in Go