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Database Systems Reference Library

This page is a verified index of primary sources for database management systems: official documentation, developer and API portals, source repositories, SDKs, downloadable or offline documentation, a two-track learning path, and free-access research literature.

It is a navigation layer, not a tutorial. Where the rest of this book explains a concept, this page tells you which document to open to get the authoritative answer, and in what order to read things. Every link was HTTP-verified on the date shown below; sources that block automated checkers but work in a browser are flagged rather than silently dropped.

Relational engines, analytical and columnar systems, storage engines, lakehouse table formats, and a two-track learning path from CMU 15-445 to reading query optimizers and LSM internals.

68 entries across 8 categories, plus 53 education & reference-implementation resources (23 basic / 30 advanced), plus 14 video resources and 6 conference sources.

Every link HTTP-verified on 2026-10-07.

dev.mysql.com, IBM Docs and the ACM Digital Library return 403 to automated clients; both load normally in a browser.

Contents

1. Relational databases — open source

PostgreSQL

PostgreSQL Wiki

MySQL

MariaDB

SQLite

  • Docs: sqlite.org/docs.html
  • Developer / API: sqlite.org/c3ref/intro.html
  • Source: github.com/sqlite/sqlite
  • SDKs & repos: Amalgamation build — the entire database as one C file
  • Downloadable / offline: Complete docs downloadable as a single archive; source amalgamation too
  • Note: The most deployed database in the world and among the most readable. See arch.html for the architecture overview and whyc.html for the design rationale.

SQLite architecture

CockroachDB

YugabyteDB

TiDB

  • Docs: docs.pingcap.com/tidb/stable
  • Developer / API: docs.pingcap.com/tidb/…
  • Source: github.com/pingcap/tidb
  • SDKs & repos: MySQL-compatible; TiKV storage layer is a separate readable project
  • Downloadable / offline: Docs site; PingCAP publishes extensive design blogs
  • Note: PingCAP’s engineering writing, and awesome-database-learning, are among the best free distributed-database education.

2. Relational databases — commercial

Oracle Database

  • Docs: docs.oracle.com/en/database
  • Developer / API: oracle.com/database/technologies
  • SDKs & repos: OCI, JDBC, ODP.NET, python-oracledb
  • Downloadable / offline: Full documentation library downloadable per release
  • Note: The Concepts guide is genuinely good and free; worth reading regardless of what you run.

Microsoft SQL Server

Google Cloud Spanner

IBM Db2

  • Docs: ibm.com/docs/en/db2
  • SDKs & repos: CLI, JDBC, pureQuery
  • Downloadable / offline: IBM Docs supports PDF export
  • Note: IBM Docs 403s to automated clients; loads normally in a browser.

3. Analytical & columnar engines

DuckDB

ClickHouse

Apache Druid

Apache Pinot

Snowflake

  • Docs: docs.snowflake.com
  • Developer / API: docs.snowflake.com/en/developer
  • SDKs & repos: Snowpark, connectors, SQL REST API
  • Downloadable / offline: Docs site
  • Note: The 2016 SIGMOD paper on the architecture is the best explanation of storage/compute separation.

Google BigQuery

Amazon Redshift

Databricks

4. Storage engines & embedded key-value stores

RocksDB

LevelDB

LMDB

  • Docs: lmdb.tech/doc
  • Source: github.com/LMDB/lmdb
  • SDKs & repos: Memory-mapped B+tree with MVCC, single writer
  • Downloadable / offline: Doxygen docs
  • Note: The counterpoint to LSM trees. ~10k lines, copy-on-write B+tree.

WiredTiger

Apache Arrow

Apache Parquet

Apache ORC

5. Lakehouse table formats

Apache Iceberg

Delta Lake

Apache Hudi

6. Reference material & tooling

Use The Index, Luke

  • Docs: use-the-index-luke.com
  • SDKs & repos: SQL indexing explained for developers, across five database engines
  • Downloadable / offline: Free online; book available
  • Note: The single most useful practical resource on indexing. Most query performance problems end here.

Modern SQL

  • Docs: modern-sql.com
  • SDKs & repos: What SQL has gained since 1992 — window functions, CTEs, JSON, MATCH_RECOGNIZE
  • Downloadable / offline: Online
  • Note: Same author as Use The Index, Luke. Corrects the assumption that SQL stopped evolving.

PostgreSQL Exercises

  • Docs: pgexercises.com
  • SDKs & repos: Graded SQL exercises against a real schema
  • Downloadable / offline: Online

explain.depesz.com

  • Docs: explain.depesz.com
  • SDKs & repos: Makes PostgreSQL EXPLAIN output readable
  • Downloadable / offline: Web tool

SQL Style Guide

  • Docs: sqlstyle.guide
  • SDKs & repos: Consistent SQL formatting conventions
  • Downloadable / offline: Online

DB-Engines Ranking

  • Docs: db-engines.com/en/ranking
  • SDKs & repos: Popularity tracking across 400+ systems
  • Downloadable / offline: Web
  • Note: Methodology is popularity-based, not technical. Useful for trends, not for selection.

7. Query engines, streaming and the surrounding ecosystem

Apache DataFusion

  • Docs: datafusion.apache.org
  • Developer / API: docs.rs/datafusion
  • Source: github.com/apache/datafusion
  • SDKs & repos: Extensible query engine in Rust built on Arrow; used as a component inside other databases
  • Downloadable / offline: Docs site
  • Note: The easiest modern query engine to read and embed. Good entry point to vectorized execution in Rust.

Apache Calcite

Trino

Polars

Materialize

  • Docs: materialize.com/docs
  • Source: github.com/MaterializeInc/materialize
  • SDKs & repos: Incremental view maintenance over streams, built on timely/differential dataflow
  • Downloadable / offline: Docs site
  • Note: Differential dataflow is one of the genuinely novel ideas in this space. Worth reading even if you never deploy it.

RisingWave

Debezium

Vitess

pgvector

SQLGlot

8. Research papers & open-access literature

arXiv

  • Docs: arxiv.org
  • Developer / API: info.arxiv.org/help/api/index.html
  • SDKs & repos: Preprints across all of CS; most systems, ML and PL work appears here before publication
  • Downloadable / offline: Every paper is a free PDF. Bulk access documented at info.arxiv.org/help/bulk_data/index.html; a full-text API at export.arxiv.org
  • Note: Not peer-reviewed. Treat an arXiv-only paper as a claim, not a result — but it is where you will read almost everything first.

ar5iv

  • Docs: ar5iv.labs.arxiv.org
  • SDKs & repos: Renders any arXiv paper as responsive HTML instead of PDF
  • Downloadable / offline: Free; swap arxiv.org/abs/ID for ar5iv.labs.arxiv.org/html/ID
  • Note: Makes papers readable on a phone and searchable in-page. Underused.

alphaXiv

  • Docs: alphaxiv.org
  • SDKs & repos: arXiv papers with a public comment and discussion layer
  • Downloadable / offline: Free
  • Note: Useful when a paper is contested — the discussion often contains the critique you were looking for.

Semantic Scholar

  • Docs: semanticscholar.org
  • Developer / API: api.semanticscholar.org/graph/v1
  • SDKs & repos: 200M+ papers with citation graph, influential-citation scoring and TLDR summaries
  • Downloadable / offline: Free Graph API (semanticscholar.org/product/api), bulk datasets available on request
  • Note: The best free citation graph. ‘Highly influential citations’ is a genuinely useful filter for finding what actually mattered.

OpenAlex

  • Docs: openalex.org
  • Developer / API: api.openalex.org/works
  • SDKs & repos: Fully open catalogue of works, authors, venues and institutions; successor to Microsoft Academic Graph
  • Downloadable / offline: Entirely free API with no key required; complete database snapshots downloadable
  • Note: The only large-scale bibliographic database that is open all the way down, including bulk snapshots.

DBLP

  • Docs: dblp.org
  • Developer / API: dblp.org/faq/13501473.html
  • SDKs & repos: Authoritative CS bibliography — complete author and venue listings
  • Downloadable / offline: Free; full XML dump downloadable
  • Note: The fastest way to find everything a given researcher has published, and to see a conference’s full programme by year.

OpenReview

  • Docs: openreview.net
  • Developer / API: docs.openreview.net
  • Source: github.com/openreview
  • SDKs & repos: ICLR, NeurIPS, COLM and dozens of other venues — papers plus the full review threads
  • Downloadable / offline: Free; REST API
  • Note: Reading the reviews and author rebuttals teaches you how the field evaluates work. Nothing else exposes this.

CORE

  • Docs: core.ac.uk
  • Developer / API: core.ac.uk/services/api
  • SDKs & repos: Aggregates 300M+ open-access papers from repositories worldwide
  • Downloadable / offline: Free API and bulk datasets
  • Note: Good for finding the green open-access copy when a publisher’s version is paywalled.

Unpaywall

  • Docs: unpaywall.org
  • Developer / API: api.unpaywall.org
  • SDKs & repos: Finds legal free copies of paywalled papers via DOI
  • Downloadable / offline: Free API; browser extension
  • Note: Legal, author-deposited copies only. Install the extension and most paywalls simply stop appearing.

Papers We Love

  • Docs: paperswelove.org
  • Source: github.com/papers-we-love/papers-we-love
  • SDKs & repos: A curated, categorised repository of classic CS papers with local meetup talks
  • Downloadable / offline: Repo cloneable; many PDFs mirrored in-repo
  • Note: The best starting point if you do not yet know which papers matter in a subfield.

The Morning Paper (archive)

  • Docs: blog.acolyer.org
  • SDKs & repos: Adrian Colyer’s daily paper summaries, 2014-2021
  • Downloadable / offline: Free archive, still online
  • Note: No longer updated, but the back catalogue of ~1000 summarised papers is one of the great free CS resources.

USENIX Proceedings

  • Docs: usenix.org/publications/proceedings
  • SDKs & repos: OSDI, SOSP (co-published), NSDI, ATC, FAST, Security — the core systems venues
  • Downloadable / offline: Every paper free, immediately, with no membership. Often with recorded talks
  • Note: USENIX made everything open access years before the rest of the field. If a systems paper exists, check here first.

ACM Digital Library

  • Docs: dl.acm.org
  • SDKs & repos: SIGMOD, ASPLOS, PLDI, POPL, SoCC and the ACM journals
  • Downloadable / offline: Partly open: ACM Open and author-paid OA papers are free; others are paywalled
  • Note: 403s to automated clients; loads in a browser. For paywalled items, check arXiv, the author’s homepage or Unpaywall first — the free copy usually exists.

IEEE Xplore

  • Docs: ieeexplore.ieee.org
  • SDKs & repos: ISCA, MICRO, HPCA and the IEEE journals
  • Downloadable / offline: Mostly paywalled; abstracts free
  • Note: Almost always worth searching the author’s page or arXiv instead. Architecture authors in particular post preprints widely.

DROPS / LIPIcs (Dagstuhl)

  • Docs: drops.dagstuhl.de
  • SDKs & repos: ECOOP, ITP, CONCUR, SAT and many theory venues
  • Downloadable / offline: 100% open access, free PDFs, Creative Commons licensed
  • Note: A fully open publisher. Every paper, always free, no exceptions.

arXiv cs.DB (Databases)

  • Docs: arxiv.org/list/cs.DB/recent
  • SDKs & repos: Database preprints
  • Downloadable / offline: Free
  • Note: Most PVLDB submissions appear here first.

PVLDB

  • Docs: vldb.org/pvldb
  • SDKs & repos: Proceedings of the VLDB Endowment — the main database venue
  • Downloadable / offline: 100% open access, every volume, free PDFs
  • Note: Fully open since inception. The single best free database paper archive.

CIDR

  • Docs: cidrdb.org
  • SDKs & repos: Conference on Innovative Data Systems Research — biennial, visionary, short papers
  • Downloadable / offline: All papers free
  • Note: Often the most interesting reading of the three main venues. Industry systems get described here first.

ACM SIGMOD

  • Docs: sigmod.org
  • SDKs & repos: The other flagship database venue
  • Downloadable / offline: Proceedings via ACM DL; many authors post preprints
  • Note: Check arXiv or the author’s page before hitting the ACM paywall.

Database of Databases (dbdb.io)

  • Docs: dbdb.io
  • Source: github.com/cmu-db/dbdb.io
  • SDKs & repos: A catalogue of 1000+ database systems with their architectural properties and references
  • Downloadable / offline: Free; data in the repo
  • Note: CMU-maintained. Filter by storage model, concurrency control or query interface to find comparable systems fast.

The Red Book

  • Docs: redbook.io
  • SDKs & repos: Readings in Database Systems, 5th edition — classic papers with editorial commentary
  • Downloadable / offline: Free online
  • Note: Stonebraker and Hellerstein telling you why each paper mattered. Read the commentary even if you skip the papers.

Education & reference implementations

Two tracks: Basic builds the foundations, Advanced is about reading and extending real implementations. Everything listed is free and publicly accessible.

Basic

23 resources across 6 topics.

The course to do first

  • CMU 15-445 Database Systems — Andy Pavlo’s undergraduate course. Full video lectures, slides, and C++ projects where you build a buffer pool, B+tree, query executor and concurrency control. Free and complete — better than most paid programmes.
  • CMU Database Group YouTube — Every lecture, plus the seminar series where real system architects explain their designs.
  • db.cs.cmu.edu — The group’s hub: courses, seminars, the Database of Databases.
  • Berkeley CS186 — The other strong public undergraduate course. Different emphasis, good second pass.

Foundations worth the time

  • Use The Index, Luke — Learn indexing properly before learning anything else about performance.
  • Modern SQL — Window functions and CTEs will change how you write queries.
  • PostgreSQL Exercises — Practise against a real schema with immediate feedback.
  • SQL Style Guide — Short. Adopt it and stop arguing about formatting.

Start with a readable system

The reference documentation to learn to navigate

Build intuition about systems

Finding and reading papers

  • Papers We Love — Start here when you do not yet know which papers matter. Curated by subfield, with recorded talks.
  • The Morning Paper archive — Around a thousand papers summarised in plain language. No longer updated; still one of the best free CS resources.
  • Semantic Scholar — Free citation graph. The ‘highly influential citations’ filter is the fastest way to find what a paper actually changed.
  • Unpaywall — Install the extension. Most paywalls stop appearing, legally, because the author deposited a copy.
  • ar5iv — Read any arXiv paper as HTML instead of a two-column PDF. Swap arxiv.org/abs for ar5iv.labs.arxiv.org/html.

Advanced

30 resources across 6 topics.

Graduate coursework

  • CMU 15-721 Advanced Database Systems — In-memory, columnar, vectorized and compiled query execution. Paper-driven, all video online. The best advanced database course available free.
  • CMU 15-445 — Do the projects even if you only watch 15-721. The implementation work is where the learning is.
  • CMU Database Group seminar series — Architects of real systems explaining their internals — Snowflake, DuckDB, TiDB and dozens more.
  • Berkeley CS186 — Public projects with a solid concurrency-control component.

Query processing & optimization

  • DuckDB source — Modern vectorized execution in readable C++. The best codebase to study push-based execution.
  • ClickHouse source — Extreme-performance columnar execution; aggressive specialization everywhere.
  • Apache Arrow columnar spec — Short spec that explains why everything in analytics converged on this layout.
  • Parquet format spec — Encodings, statistics, predicate pushdown — all in one document.
  • Apache Calcite — Cost-based optimization as a reusable component. Read the rule system.

Storage engines

  • RocksDB wiki — LSM compaction strategies, write stalls, tuning. Deeper than most textbooks.
  • RocksDB source — The reference LSM implementation.
  • LevelDB — Read this first — same ideas, a fraction of the code.
  • LMDB — Copy-on-write B+tree with MVCC. The intellectual opposite of LSM; study both.
  • WiredTiger — B-tree and LSM in one engine, in production under MongoDB.
  • databass.dev — Ties the storage-engine literature together coherently.

Transactions, concurrency & distributed SQL

  • CockroachDB RFCs — The docs/RFCS/ directory records real distributed-SQL design arguments in detail. Rare and valuable.
  • TiDB — Percolator-style transactions over a separate TiKV storage layer.
  • awesome-database-learning — PingCAP’s curated path through papers, courses and source. Excellent.
  • YugabyteDB — Reuses PostgreSQL’s query layer over a distributed store.
  • Cloud Spanner docs — TrueTime and external consistency, documented by the people who shipped it.
  • Designing Data-Intensive Applications — Chapter 7 and 9 on transactions and consistency remain the clearest treatment.

Lakehouse & modern data architecture

Papers & research venues

  • The Red Book — Start here. Classic papers with commentary explaining why each mattered.
  • VLDB / PVLDB — All papers free. The main database research venue.
  • ACM SIGMOD — The other main venue. ACM DL 403s to bots; accessible in a browser, and most papers are also on authors’ pages.
  • CIDR — Biennial, visionary, short papers. Often the most interesting reading of the three.
  • awesome-database-learning — Also a good paper index organised by subsystem.

Video courses, channels & talks

14 resources across 2 groups. Every channel and playlist below was fetched and title-verified on 2026-10-09. Handles drift and several plausible-looking handles resolve to the wrong channel, so a 200 response is not proof of identity — the links here were each checked against the channel title.

Channels & conference recordings

  • Hussein Nasser — Database internals — indexing, isolation levels, replication — explained from first principles.
  • MySQL — Official MySQL channel: product deep dives and conference talks.
  • MongoDB — Official MongoDB channel: internals, aggregation, Atlas talks.
  • Redis — Official Redis channel: internals, modules, and Redis University material.
  • Confluent — Kafka Summit talks and stream-processing design sessions — the canonical Kafka video record.
  • USENIX — Conference recordings for most USENIX papers — free video, the fastest route into a systems paper.
  • InfoQ — Conference keynotes and architecture talks — good for orientation, verify specifics elsewhere.
  • Papers We Love — Recorded paper walkthroughs — watch one before you read the PDF.
  • VLDB — VLDB conference recordings; the channel only holds one edition, so treat it as a sample, not an archive.
  • Percona — Percona Live talks on MySQL, PostgreSQL and MongoDB internals — practitioner depth, engine-specific.
  • ClickHouse — Vendor channel, but unusually technical: columnar storage internals and query-execution talks.
  • Yugabyte — Distributed SQL internals, including consensus and transaction-design talks.

Lectures & playlists

Note: Vendor channels are useful for internals of their own engine and useless for anything else; pair them with the USENIX and paper-walkthrough material.

Conference videos, notes & archives

6 resources across 2 groups. Conference recordings are the primary-source tier of video: the speaker is usually an author of the paper, and where a talk exists the proceedings entry is often open at the same link. Every URL here returned 200 on 2026-10-09 unless the note says otherwise.

Database conferences are unusually open — PVLDB is fully open access, and the vendor conferences publish good internals talks.

Conference channels & video archives

  • VLDB — PVLDB is fully open access, which is why it is the citation you can actually read.
  • USENIX FAST ’25 — Storage conference, but the storage-engine papers here are database internals.
  • Percona Live — Practitioner conference on MySQL, PostgreSQL and MongoDB; talks published on the Percona channel.
  • CMU 15-445 course site — Slides, notes and open labs to go with the playlist above; the homework is the point.
  • FOSDEM video archive — Databases and PostgreSQL devrooms.

Notes, proceedings & paper-adjacent archives

  • USENIX ;login: — Where the operational side of database work gets written up.

If you only do three things

  1. Do CMU 15-445. Videos, slides and C++ projects, all free. Build a buffer pool and a B+tree yourself.
  2. Read sqlite.org/arch.html, then the SQLite source. A complete database you can actually hold in your head.
  3. Work through Use The Index, Luke. Most real-world query performance problems are solved by this one resource.

Honest notes

  • PostgreSQL’s manual is the best documentation in this field. Learn to navigate it; it rewards the investment for years.
  • RocksDB’s wiki is better than most database textbooks on LSM trees, compaction and write amplification.
  • Read LevelDB before RocksDB, and LMDB alongside both. LSM versus copy-on-write B+tree is the central storage trade-off.
  • The Iceberg and Delta specs are short. Read them directly rather than vendor explainers.
  • DB-Engines ranks by popularity, not merit. Useful for trends only.