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Show HN: A Database Written in Golang (github.com/sahilb315)
277 points by Sahil121 54 days ago | hide | past | favorite | 68 comments
Recently created a minimal persistent relational database in Go. Main focus was on implementing & understanding working the of database, storage management & transaction handling. Use of B+ Tree for storage engine(support for indexing), managing a Free List (for reusing nodes), Support for transactions, Concurrent Reads. Still have many things to add & fix like query processing being one of the main & fixing some bugs

Repo link - https://github.com/Sahilb315/AtomixDB

Would love to hear your thoughts




Cool!

You watched CMU's intro to Database sytems, right? It's really good and thorough. It will save you of some common pitfalls and can help you navigate the trade-offs.

https://www.youtube.com/watch?v=otE2WvX3XdQ&list=PLSE8ODhjZX...


I really have liked the current Optimizer series. So much amazing info.

I hope some company that heavily relies on Postgres sponsors a project to replace the optimizer with a more modern implementation. I feel like for any large applications with olap style queries (even if on the OLTP database) will benefit incredibly from that work. SQL Servers optimizer was light-years ahead of Postgres when I worked with it last over a decade ago.


Sadly, most of those corporations would rather spend millions in proprietary solutions than give back 100k to the community. I've seen it first hand many times. They only give money if they absolutely have to.


I also recommend "Database Internals" to people. An invaluable book, the logical next read after "Designing Data-Intensive Applications". It's the best and most approachable resource on distributed systems and database consistency / performance tradeoffs I have found.


Oh thanks for the link, this is really great!


sure man


Looks fun, but the intro requirement is "Knows C++" - that's kinda a non starter right?


I'm sure that's for the homework.


Other databases written in Go:

- TiDB by PingCAP

- Vitess by PlanetScale

Both are basically only the SQL part as TiDB uses TiKV (written in Rust) and Vitess uses MySQL.

For those who want to implement a database in Go but without having to implement a network protocol there is go-mysql, which allows you to do this: https://github.com/go-mysql-org/go-mysql/blob/master/cmd/go-... As demonstration I created a networked SQLite: https://github.com/dveeden/go-mysql-examples/blob/main/go-my...

Both TiDB and Vitess have parsers that can be used outside standalone. So if you only want to implement your own on disk format, this can help.

Note that I'm working for PingCAP on TiDB and I'm also a co-maintainer for go-mysql.


We use Tidb at work at scale. Great product! Was looking at the source today to understand an error code.


Vitess came from YouTube


Didn't the Vitess team found planetscale?


Yes! The founders of PlanetScale were the co-creators of Vitess at YouTube, where it was built to handle MySQL scalability. PlanetScale builds on Vitess but offers a managed, developer-friendly experience.


Someone asked about resources and I ran into this while evaluating embedded db options for a golang project - it's a collection of db components implemented in golang:

https://github.com/thomasjungblut/go-sstables


thank you for referring, feel free to ask any questions you may have


You might be interested in this golang db from mit’s database systems course:

https://github.com/MIT-DB-Class/go-db-2024 https://dsg.csail.mit.edu/6.5830/


will surely checkout thanks man


This looks like a good exploratory project!

One thing I’d add to the readme is an example of how you’d use the database in an example application. From the docs, it’s clear that this isn’t a sql database (yet?), so it would be good to have an example to see how to use the database.

It might also be nice to have a description of what happens when you insert or get a record, so others can learn from the code too. Or can you comment here about what your favorite part of the code is? What did you figure out that you didn’t know before? If you’re using the project to learn about databases, what have you learned so far?


thanks man yes currently it is not a fully sql database (have to add query support) My fav part of code is the data retrieval code because had some issues there & got to know lot about it

Learnt about B+ Trees, transactions, managing concurrent reads & data presistence


I didnt look into it yet but i already wanted to say - cuz of curiosity i build my own graph database in golang :) and i learned alot. so i absolutly understand why you did it and what experiences you probably made on the way :D

congratz !


Is this published anywhere?


Kinda. So first i went for a standalone application back than to use it as storage/database. This part is archived now. it was released under: https://github.com/voodooEntity/slingshotdb

At this point i think its important to mention that its nativly an in-memory graph database/storage.

At some point (4-5 years ago) i decided to change the way i handle it. Since im using the storage in many private projects, and there was no real traction (while also maintaining a database is quite some work) i decided i gonne change the way i handle it away from a standalone database to a library that works as an in-memory graph storage.

Also i added a custom query language including builder (the queries are 100% json compatible so you can in theory build queries from whatever language and transmit it via json.

The library is released under : https://github.com/voodooEntity/gits

Currently im completly reworking the query parser but since this is a privat project and im the only maintainer it may take some to to finish it. The update will takle some smaller bugs in the query parser that can occur on very complex nested queries and also will optimize query speeds. I cant provide a date when the update will occure i only can say it will (because i need it myself).

Finally said: The strength of gits is to be very fast (hence in memory handling) and easy to use from golang. Its threadsafe by default.


thanks man


If you are wanting proper SQL command support, you could copy the SQLite parser approach. Properly parsing all valid command texts is not a problem that I would find compelling unless I was being compensated for it.

https://www.sqlite.org/lemon.html

You could probably use something like participle, but you'd have to translate the grammar.

https://github.com/alecthomas/participle


You can use https://github.com/cockroachdb/cockroachdb-parser which is basically PGSQL compatible parser implemented in golang


I do have a big collection of LALR(1) grammars to test/study/develop/document here https://mingodad.github.io/parsertl-playground/playground/ including sqlite, tidb, vites, postgresql, mysql, ...


yes man have to work on adding the sql cmd support thanks for the links


Nice, did you follow a course or any resources to build it? Please share, I have a similar goal. Thank you.


I took a quick glance at the code, I believe it may build upon "Build Your Own Database From Scratch in Go" [0]. The first part of the book is available for free on the author's website, along with information on how to purchase the full book (which includes source code).

I share the same goal and am working through the material after working through Codecrafters' "Build your own SQLite" [1]. Good luck!

I apologize in advance for mistakes (formatting, et cetera). I just registered this account to point you toward resources I found helpful.

[0] https://build-your-own.org/database/

[1] https://app.codecrafters.io/courses/sqlite/overview


Does something like this exist for java, don't want to take the burden of a new language.


I don't think these things really fit the bill, but this is closest I could find. All the codecrafters stuff is focused on reading from a sqlite DB. A great start, but you're not implementing B+ trees.

Hope this gives you some options.

https://github.com/Arminas42/build_your_own_database

https://github.com/search?q=codecrafters+sqlite-java+languag...


it's not that hard, you should try it :)


Looks like a start. Keep it up, keep learning. Definitely check out https://www.youtube.com/c/CMUDatabaseGroup

Great lectures on relational databases and more.


Congratulations on a great exploratory project!

It takes me back to my school years. I never got as far as you (not by any long stretch actually), but I did enjoy creating the storage layer of a database from scratch. To actually have to deal with, instead of just think of, all the edge cases, is quite the transformative experience.

As a humble suggestion, since it seems your goal is to understand how relational databases work and not necessarily to write a new database that will compete with others, maybe don't make it an SQL one? We've got enough of those, and not enough of the others. Would be nice to have a new relational DB using Tutorial D as its language for example.

Keep hacking!


thanks for the suggestion man, will definitely think about this


This is so nice!

I created an email verifier project in Go to check MX records, SMTP server status, and existence in the disposable list.

Project - https://github.com/hsnice16/email-verifier


Maybe a good place to ask: good sdks or libraries for reading parquet?


to also share a reference - here's an on disk hashmap that uses mmap that I made in golang: https://github.com/snissn/gomap


excellent, would love to hear more about resources you used while implementing


followed this book - https://build-your-own.org/database/


Cool!

btw, README says Go 1.17+ is required, but go.mod says 1.23+.


You should trust that the readme is up to date


With Go toolchain [1.17, 1.23.1], it fails to build.


Best part: a go.mod with 0 dependencies!


Now that is impressive. Gotta love zero dependency projects.


If folks would like to see more examples of databases built to teach oneself, they get shared on the /r/databasedevelopment subreddit not infrequently.

Some recent ones:

https://www.reddit.com/r/databasedevelopment/comments/1hyig8...

https://www.reddit.com/r/databasedevelopment/comments/1ha5cc...

https://www.reddit.com/r/databasedevelopment/comments/1dqgms...

https://www.reddit.com/r/databasedevelopment/comments/1ix5dz...

https://www.reddit.com/r/databasedevelopment/comments/18knod...

https://www.reddit.com/r/databasedevelopment/comments/1h3w70...

https://www.reddit.com/r/databasedevelopment/comments/1gk18n...

https://www.reddit.com/r/databasedevelopment/comments/1bemf9...

https://www.reddit.com/r/databasedevelopment/comments/1iw6cx...


Here's my list (probably not all of them)

https://github.com/FireScroll/FireScroll/

https://github.com/danthegoodman1/DurableStreams (brand new)

https://github.com/danthegoodman1/ObjectKV

https://github.com/danthegoodman1/WriteAhead

https://github.com/danthegoodman1/icedb (most popular)

https://github.com/danthegoodman1/Percolators (kind of a DB on top of a DB, technically just transactions tho)

there are others that might not fit exactly what you're looking for


Wow, what great resources. Thanks for sharing bud :)


Nice, thanks! I didn‘t know there was a subreddit for that.


Hi Phil, I thought I'd find you here! Love your blog!


Glad to hear it. :)


How do you connect to it and actually use it? Does it behave like a SQL database? Row-based? Column-based? Good for analytical workloads? Document store? Redis/memcached database? What are it's strengths or weaknesses?

Cool accomplishment in and of itself but hard for anyone here to really give you any criticism or feedback without understanding where it excels and how to work with it.


> Main focus was on implementing & understanding working the of database

I think this clearly describes what was the goal.


Yep... but there are dozens of different types of databases out there. There is no way to look at this codebase and give any kind of feedback one way or the other without that understanding, particularly with zero usage examples. Which is what the OP is asking about.


> There is no way to look at this codebase and give any kind of feedback

Less than a minute and I know how to use it. It's not complicated. The source code is available and fairly easy. If you can't figure out how to use it in a trivial amount of time, you aren't going to be able to offer anything of value. When did HN go from being about interesting stuff to making bold, ignorant statements like "There is no way to look at this codebase and give any kind of feedback one way or the other without that understanding."

You should know better.


[flagged]


yeah as a dev/non-go person don't know how it works either. I assume main.go is where it starts but then what... I see a commands maybe it works by CLI? idk either


Yes it's a CLI REPL, you build and run the binary using the instructions in the README and then create/insert/select from it by typing those commands into the CLI.

Currently there's no way to connect to it like you would a normal SQL db, but you could embed it like you would sqlite.


Hopefully there is a help/man


If you're not a developer then you're not the target audience for this.


You're a "dev," but don't seek out test folders/files for use case examples?

Don't let your employer know...


They can be a dev and not want to have to clone and explore the code. There's tons of little bits of friction that're not addressed by the "face" of the repo. E.g. The readme doesn't seem to imply how to connect to this database (the answer is you write to its stdin, it's not socket based).

We're not at work here. Low effort posts are allowed though not encouraged. Implying that making a low effort post somehow makes you not a developer ("you're a 'dev' but don't seem out tests?") is it's own low effort post, while also being hurtful.

Please, let's keep things kind, focused, and clear.


It does not seem to speak SQL:

    $ git clone git@github.com:Sahilb315/AtomixDB.git
    Cloning into 'AtomixDB'...
    $ cd AtomixDB/
    $ go run .
    Welcome to AtomixDB
    Available Commands:
      CREATE       - Create a new table
      INSERT       - Add a record to a table
      DELETE       - Delete a record from a table
      GET          - Retrieve a record from a table
      UPDATE       - Update a record in a table
      BEGIN        - Begin new transaction
      COMMIT       - Commit transaction
      ABORT        - Rollback transaction
      EXIT         - Exit the program
    
    > create
    Enter table name: foo
    Enter column names (comma-separated): bar,baz
    Enter column types (comma-separated as numbers): 1,2
    Enter indexes (format: col1+col2,col3, ... or leave empty):
    Table 'foo' created successfully.
    > get
    Enter table name: foo
    
    Select query type:
    1. Index lookup (primary/secondary key)
    2. Range query
    3. Column filter
    Enter choice (1, 2 or 3):
It looks like records are stored in rows: https://github.com/Sahilb315/AtomixDB/blob/64c95afa8e574595c...

I do find the source to be well organized and quite readable. Especially if you runs the commands in the cli and then trace how they are each implemented.


yes man it is currently a sql db, have to work on adding query language thanks for checking it out


it is kind of a sql db but currently does not have the query lang (sql lang) & data is stored in tables similar to other relational DBs. Still have a lot of stuff to add & fix Will add more detail to it


[flagged]


"Main focus was on implementing & understanding working the of database, storage management & transaction handling."

Obviously OP wrote it to understand database theory & implementation.


That a database written in an AOT compiled managed language is possible, for example.

Specially relevant, because it used to be that writing database engines used to be considered systems programming, and we all know managed languages cannot be possible used for such tasks. /s


It's hackernews, basically every old thing has to be reinvented in the "language of the week", be it go, rust, ruby, or whatever was before that.

From a learning perspective, nice project for OP, for 'advertising' it, i'd prefer the "what's better than the alternatives" instead of focusing on the language.


I want more Ada / SPARK and Factor. :D




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