This is not a book, but we did write up some documentation for developers that gives a nice overview of how the optimizer works:
https://github.com/cockroachdb/cockroach/blob/master/pkg/sql...
Might be worth a read if you're interested in implementation techniques.
In How We Built a Cost-Based SQL Optimizercockroachdb
cockroach
Go2014–2026
cockroachdb / cockroach
cockroach
CockroachDB — the cloud native, distributed SQL database designed for high availability, effortless scale, and control over data placement.
114Distinct people
170Mentions
1Explicit recommenders
32.6KGitHub stars
What to know before exploring
What it is
CockroachDB — the cloud native, distributed SQL database designed for high availability, effortless scale, and control over data placement.
GitHub
Where it is used
- DoorDash — DoorDash runs CockroachDB as a fully abstracted internal database service for its engineering organization. DoorDash leverages it to meet availability goals at massive scale. Source
- City Storage Systems — City Storage Systems uses CockroachDB to run Tier 0 applications, migrating their order management system and user authentication platform to it. They replaced some PostgreSQL use cases with CockroachDB for these critical apps. Source
- 1 more documented example
What people are saying
Tried it before. Compatibility depends on how complicated your SQL is. There's a detailed list of supported syntax which is getting better every release but it's best for…
manigandham used a recommendation phrase. One indexed comment matches. This is a phrase match, not a verdict.
No classified warning is attached to this page. Read the discussions before treating silence as approval.
Also in these discussions
- kubernetes/kubernetes · linked in 2 of the same discussions
- moby/moby · linked in 2 of the same discussions
- pingcap/tidb · linked in 2 of the same discussions
Mentioned in the same Hacker News threads. That is not proof they are substitutes.
This week on Hacker News
Nov 8–Nov 15 UTC · Direct repository links and separately labeled related project stories. Indexed through 11/15/2026, 12:45:45 PM UTC.
No direct repository links were found in the indexed HN discussions over the past seven days. Older discussions are available below.
Mentions over time
HN mentions by year170 dated mentions
Observed mentions: 2014-05-26 11:44:43 UTC to 2026-08-11 19:04:13 UTC.
* An incomplete calendar period is marked with an outlined bar. Its count is not directly comparable with a full period.
Counts come from the repository’s dated source evidence. Index cutoff: 2026-11-02 08:16:59 UTC.
View mention counts and date ranges
| Period | Start (UTC) | End (exclusive, UTC) | Mentions | Submissions | Comments |
|---|---|---|---|---|---|
| 2014 | 2014-01-01 00:00:00 UTC | 2015-01-01 00:00:00 UTC | 9 | 6 | 3 |
| 2015 | 2015-01-01 00:00:00 UTC | 2016-01-01 00:00:00 UTC | 17 | 2 | 15 |
| 2016 | 2016-01-01 00:00:00 UTC | 2017-01-01 00:00:00 UTC | 20 | 0 | 20 |
| 2017 | 2017-01-01 00:00:00 UTC | 2018-01-01 00:00:00 UTC | 46 | 1 | 45 |
| 2018 | 2018-01-01 00:00:00 UTC | 2019-01-01 00:00:00 UTC | 8 | 0 | 8 |
| 2019 | 2019-01-01 00:00:00 UTC | 2020-01-01 00:00:00 UTC | 18 | 1 | 17 |
| 2020 | 2020-01-01 00:00:00 UTC | 2021-01-01 00:00:00 UTC | 16 | 0 | 16 |
| 2021 | 2021-01-01 00:00:00 UTC | 2022-01-01 00:00:00 UTC | 4 | 0 | 4 |
| 2022 | 2022-01-01 00:00:00 UTC | 2023-01-01 00:00:00 UTC | 14 | 1 | 13 |
| 2023 | 2023-01-01 00:00:00 UTC | 2024-01-01 00:00:00 UTC | 4 | 0 | 4 |
| 2024 | 2024-01-01 00:00:00 UTC | 2025-01-01 00:00:00 UTC | 10 | 0 | 10 |
| 2025 | 2025-01-01 00:00:00 UTC | 2026-01-01 00:00:00 UTC | 3 | 1 | 2 |
| 2026 (partial) | 2026-01-01 00:00:00 UTC | 2027-01-01 00:00:00 UTC | 1 | 0 | 1 |
From the project README
An excerpt from the repository, fetched Nov 13, 2026.
Read the project’s introduction
CockroachDB is a cloud-native distributed SQL database designed to build,
scale, and manage modern, data-intensive applications.
What is CockroachDB?
Docs
Starting with Cockroach Cloud
Starting with CockroachDB
Client Drivers
Deployment
Need Help?
Contributing
Design
Comparison with Other Databases
See Also
What is CockroachDB?
CockroachDB is a distributed SQL database built on a transactional and
strongly-consistent key-value store. It scales horizontally;
survives disk, machine, rack, and even datacenter failures with
minimal latency disruption and no manual intervention; supports
strongly-consistent ACID transactions; and provides a familiar
SQL API for structuring, manipulating, and querying data.
For more details, see our product overview, FAQ or architecture document.
Docs
For guidance on installation, development, deployment, and administration, see our User Documentation.
Starting with CockroachCloud
We can run CockroachDB for you, so you don't have to run your own cluster.
See our online documentation: Quickstart with CockroachCloud
Starting with CockroachDB
Install CockroachDB: using a pre-built executable or build it from source.
Start a local cluster and connect to it via the built-in SQL client.
Learn more about CockroachDB SQL.
Use a PostgreSQL-compatible driver or ORM to build an app with CockroachDB.
Explore core features, such as data replication, automatic rebalancing, and fault tolerance and recovery.
Client Drivers
CockroachDB supports the PostgreSQL wire protocol, so you can use any available PostgreSQL client drivers to connect from various languages.
For recommended drivers that we've tested, see Install Client Drivers.
For tutorials using these drivers, as well as supported ORMs, see Example Apps.
Deployment
CockroachCloud - Steps to create a free CockroachCloud cluster on your preferred Cloud platform.
Manual - Steps to deploy a CockroachDB cluster manually on multiple machines.
Cloud - Guides for deploying CockroachDB on various cloud platforms.
Orchestration - Guides for running CockroachDB with popular open-source orchestration systems.
Need Help?
CockroachDB Community Slack - Join our slack to connect with our engineers and other users running CockroachDB.
CockroachDB Forum and Stack Overflow - Ask questions, find answers, and help other users.
Troubleshooting documentation - Learn how to troubleshoot common errors, cluster setup, and SQL query behavior.
For filing bugs, suggesting improvements, or requesting new features, help us out by opening an issue.
Building from source
See our wiki for more details.
Contributing
We welcome your contributions! If you're looking for issues to work on, try looking at the good first issue list. We do our best to tag issues suitable for new external contributors with that label, so it's a great way to find something you can help with!
See our wiki for more details.
Engineering discussions take place on our public mailing list, cockroach-db@googlegroups.com. Also please join our Community Slack (there's a dedicated #contributors channel!) to ask questions, discuss your ideas, and connect with other contributors.
Design
For an in-depth discussion of the CockroachDB architecture, see our
Architecture
Guide.
For the original design motivation, see our design
doc.
Licensing
All versions released on or after November 18, 2024 (specifically, major version series v24.3 and later, and patch fixes for v23.1.29+, v23.2.16+, v24.1.7+, and v24.2.5+) are published under the CockroachDB Software License (CSL). Source code in a given file is licensed under the CSL and the copyright belongs to The Cockroach Authors unless otherwise noted in the file or in a LICENSE or README file located in the same or a parent directory of the file.
Comparison with Other Databases
To see how key features of CockroachDB stack up against other databases,
check out CockroachDB in Comparison.
See Also
Tech Talks (by CockroachDB founders, engineers, and customers!)
CockroachDB User Documentation
The CockroachDB Blog
Key design documents
Serializable, Lockless, Distributed: Isolation in CockroachDB
Consensus, Made Thrive
Trust, But Verify: How CockroachDB Checks Replication
Living Without Atomic Clocks
The CockroachDB Architecture Document
Read the full README on GitHubWhat Hacker News says
8 sourcesTo be clear, the Exodus/Volcano/Cascades foundation includes more than just the Memo. Also important is the idea that you can declaratively define rewrite rules and generate parts of your optimizer. Also, optimization proceeds top-down rather than bottom-up, which allows you to prune the search space as you explore, as well as open up important lines of communication from nodes higher in the tree to nodes lower in the tree (i.e. required physical properties, which I explain in another HN comment).
You're correct on your points (search space can be smaller/faster, with less memory usage). In addition, when you're dealing with a piece of software as complex as a SQL optimizer, choosing modular, elegant abstractions can make a big difference in terms of understandability, maintainability and extensibility of the codebase. That in turn leads
Read the rest
to fewer bugs, such as subtle violations of logical equivalence when transforming the tree. I think the more structured, general approach to optimization allows mere mortals to manage higher levels of complexity, in which the RDBMS defines 100's of transformations, offers many join ops (hash, merge, nested, zigzag, etc.) and data types (geospatial, json, etc), as well as incorporating data locality in the new world of geo-distribution.
As one example to illustrate why there's a practical correspondence between well-designed abstractions/architecture and correctness (i.e. fewer bugs), consider these PRs that we recently merged:
https://github.com/cockroachdb/cockroach/pull/31977
https://github.com/cockroachdb/cockroach/pull/30636
These PRs randomly disable transformation rules and perturb the cost of expressions in the optimizer, in order to test alternate (but equivalent) plans. It took just 100 lines of code to add this support, because it simply plugs into the general optimization framework. And in return, our existing test cases can now test multiple different plans, allowing us to shine light into the dark corners where bugs like to hide (cockroaches, of course!).
As another example, we have a testing mode called "optsteps", which will single-step the optimizer and print out the tree after each transformation to make it easy to track down bugs. Here's an example of that output, again made possible by the extensible, modular design of the optimizer:
https://github.com/cockroachdb/cockroach/blob/master/pkg/sql/opt/norm/testdata/rul…
To me the following are the main differences:
- CRDB talks Postgres Protocol and Dialect, TiDB talks Mysql Protocol and Dialect.
- TiDB is OLTP+OLAP, CRDB is OLTP only.
- CRDB is a single binary, TiDB has more moving parts/can be used in different ways.
I picked CockroachDB because it's Follow-the-workload[0] and Interleaved tables[1] included in their Community Edition, I'm a Postgres person so it was a natural fit. Also it's the little things, I made a comment in a closed issue and somebody paid attention in less than a day[2] which makes me feel closer to them.
On the other hand, the fact that TiDB claims OLTP+OLAP feels like they're moving faster than CockroachLabs, PingCAP also says they have 25 companies using TiDB[3] where CockroachLabs has less than 10 known study cases[4].
[0]https://www.cockroachlabs.com/docs/stable/demo-follow-
Read the rest
I've been using CRDB 2.0 for a toy project for a few weeks now, today I notice 2.1 was available so I started playing with some of their new features, I ran a SQL query with correlated sub-queries and then the server crashed. It's the first time I see a crash, so I rushed to the GitHub report to report the bug and to my surprise a GitHub issue was already created for the crash[0], it included the stack trace and an anonymized version of my SQL query that caused the crash.
This really demonstrates they really care about the stability of their product, one more reason to keep recommending CockroachDB.
[0] https://github.com/cockroachdb/cockroach/issues/32048
In Managed CockroachDB: Geo-Distributed Database as a ServiceGood question! In 2.0 we only use one of the fields for the index lookup and then use the rest as a filter. For 2.1 we’re planning on augmenting our execution engine to enable making use of all the fields in a more efficient way. We have an RFC[0] describing the way our inverted indexes are designed, though not everything outlined in that document is implemented yet.
[0]: https://github.com/cockroachdb/cockroach/blob/master/docs/RF...
In CockroachDB 2.0 releasedWhen I tested CockroachDB, I did a single-node and multi-node comparison to Galera. I was ready to accept that multi-node is going to have a performance hit, but what surprised me the most was that the single-node performance was roughly 5-10 times worse with CockroachDB.
https://github.com/cockroachdb/cockroach/issues/17777#issuec...
In CockroachDB 2.0 releasedGo doesn't do that, but it enables it and I'd even say encourages it, starting from the documentation https://golang.org/doc/code.html#Library
Even projects using dep continue this pattern of pulling things from github master. I just browed through the top projects on Github for go and pretty much all of them that contained a gopkg.toml pulled in one or more things from github directly from master
https://github.com/grafana/grafana/blob/master/Gopkg.toml
https://github.com/containous/traefik/blob/master/Gopkg.toml
https://github.com/cockroachdb/cockroach/blob/master/Gopkg.t...
https://github.com/github/hub/blob/master/Gopkg.toml
These include projects like graphana, cockroachdb and hugo.
In GitHub shouldn't allow username reuseLots of comments here about lack of JSON support in gRPC - while that's true, it's relatively easily to bolt on using grpc-gateway (https://github.com/grpc-ecosystem/grpc-gateway).
Here's how we did it in CockroachDB: https://github.com/cockroachdb/cockroach/blob/24ed8df04719a1...
The supporting code (protoutil) is https://godoc.org/github.com/cockroachdb/cockroach/pkg/util/... and https://godoc.org/github.com/cockroachdb/cockroach/pkg/util/....
In Twirp: A new RPC framework for Go