How to Implement Bitmap Scans on Distributed PostgreSQL

The blog post by Tim Elgersma discusses the implementation of bitmap scans in the distributed database YugabyteDB, which aims to bridge the performance gap with PostgreSQL by allowing users to run existing Postgres applications on YugabyteDB without modifications. Bitmap scans are a crucial feature for optimizing queries with OR clauses, as they combine multiple indexes into a single efficient execution plan, reducing the need for full table scans that increase latency. Unlike PostgreSQL, YugabyteDB's storage layer requires different data structures due to its distributed nature, leading to the adaptation of bitmap scans to handle YBCTIDs instead of Postgres's TIDs. The blog highlights the unique optimizations possible in YugabyteDB, such as remote filters and aggregate pushdowns, which can outperform Postgres in certain scenarios by reducing network latency and memory usage. These enhancements are made possible by leveraging YugabyteDB's distributed architecture, allowing for efficient data retrieval and processing directly on the storage layer, ultimately providing performance improvements and a seamless migration path for existing Postgres users.