query-planner

build your own query planner

Google Cloud Spanner Query Planner Visualizer

An eBPF based query planning tracer for PostgreSQL

Run the PostgreSQL Explain Visualizer 2 (pev2) from the command line.

Context Runtime — a database query planner for LLM context. Decides what a model sees before it answers; plans it, runs it through reused substrate, and learns from the outcome.

A tiny relational database written in Go

A minimal educational relational database management system (RDBMS) implemented in Java 17. The project demonstrates a custom SQL processing pipeline, including lexer, parser, semantic analysis, query planning, optimization, and execution. It features a storage engine with heap pages, a buffer pool, and supports indexing using B-trees and Hash

In-memory SQL query engine written from scratch in C#, with a B+ tree and hash index, a cost-based query planner and Volcano-style execution with parallel aggregation. Results are verified against SQLite on 500 randomly generated queries.

A SQL database written from scratch in Rust. Passes 100% of SQLite's sqllogictest suite and shows each query running in your browser.

Hypothetical IVFFlat indexes for pgvector: test planner choices in EXPLAIN without building a physical index

Встраиваемая SQL-база данных на чистом Python: B+деревья, журнал отката, планировщик с индексами, EXPLAIN и REPL

A columnar analytical database engine built from first principles in Rust: encodings, a segment format with pushdown, a hand-written SQL parser and a logical planner.

A relational database engine written from scratch: slotted-page storage, an on-disk B+ tree, a SQL parser, a rule-based planner and a volcano executor.

A real relational database engine from scratch in pure Python, zero dependencies: checksummed paged storage, a bounded buffer pool, a B+Tree with secondary indexes and overflow pages, a WAL with crash recovery, MVCC transactions, a SQL parser + planner (joins, aggregation), a DB-API 2.0 driver, and a client/server.

Multi-tenant analytics Copilot with a semantic catalog, typed QueryPlan, governed Skills, SQL controls and Kafka tasks.

Rogue planets are starless planets, scientifically adrift in the cosmic dark alone

Small SQL query engine written from scratch in Go, with a volcano execution model, hash joins, aggregation, three-valued NULL semantics, and SQLite differential testing.

Relational SQL database written from scratch in Go that speaks the PostgreSQL wire protocol: psql, pgx and psycopg connect unchanged; WAL, B+trees, MVCC, cost-based planner; 99.98% of sqllogictest

A small SQL database you can see inside. Embedded engine in Go with B+tree storage, WAL crash recovery, and a live X-ray visualizer.

Show all plans considered by the optimizer