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 relational database built from scratch in Python: B+Trees, SQL parser and query planner, transactions, write-ahead log crash recovery

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

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.

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.

Show all plans considered by the optimizer

A SQL database in pure Python: on-disk B+trees, a query planner, crash-safe transactions. Differentially tested against SQLite.

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.

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