SQL.js: SQLite Compiled to JavaScript

https://sql.js.org/#/

by chmaynard • 6 years ago

183 38 6 years ago

sql.js.org

jitl3• 6 years ago

SQLite has a system that abstracts various low-level storage operations called VFS - this is the layer that allows SQLite to be portable across different operating systems and environments: https://www.sqlite.org/vfs.html

Recently I’ve wondered how possible it would be to implement a SQLite VFS on top of IndexedDB - and, would such a VFS be competitive in speed to using IndexedDB directly? Or, would it be equivalent to use Emscripten’s existing POSIX-ish filesystem backed by IndexedDB?

An IndexedDB VFS would allow sql.js to durably persist data in the browser.

WrtCdEvrydy• 6 years ago

Wouldn't it be better if you could directly store this data to cookies or localStorage?

Edit: The concern is always about allowing it to be easy to delete junk data.

tracker13• 6 years ago

IndexedDB should perform better without locking the browser context.

shakna• 6 years ago

The file size limits on cookies and localStorage might make it a bit impractical for the kinds of things you'd want to store in a database. You won't be caching many image files that way, for example.

jitl3• 6 years ago

Cookies are not a good spot for bulk data because each request to the server includes all the cookies. You wouldn’t want your whole SQL database included in each fetch() request.

localStorage is not durable. At Notion, we observed Chrome localStorage losing writes under load from multiple async writers. IndexedDB is the most durable option, but has quite an annoying and error-prone API, which is why it would be nice to paper over it with SQLite so browser code can use the same schemas and queries as native clients.

tracker13• 6 years ago

Similarly, would like to see SQLite work over a WASI's File System interface... best would be the ability to also support multi-process, but I don't know that it would be possible.

RcouF1uZ4gsC• 6 years ago

Recently I’ve wondered how possible it would be to implement a SQLite VFS on top of IndexedDB

What is interesting about this approach is that at least for Firefox, IndexDB is implemented using SQLite. So ultimately this approach is SQLite running in SQLite with an IndexDB layer in the middle.

jitl3• 6 years ago

Yeah, the the teetering architecture tower is certainly worth an eye-roll given that WebSQL - basically SQLite direct access - was almost accepted as a standard, but was ultimately blocked by Mozilla [https://en.m.wikipedia.org/wiki/Web_SQL_Database] while they pushed this IndexedDB monstrosity.

I am not a fan of the IndexedDB API.

bob10292• 6 years ago

What if SSDs just had an alternative interface that talked SQL? Presumably you could bake SQLite into the microcontroller and optimize perfectly for the storage scenario. Having your journaling aware of how long your supercapacitor will last in the worst case could open the door for some wild optimizations.

wtallis• 6 years ago

There have been some projects to develop SSDs that natively present a key-value storage interface, and standardization of that is pretty far along. So those drives can function as a backend for eg. a RocksDB substitute with a minimal software frontend.

But a full SQL database engine on the SSD would fall under the umbrella of computational storage, and so far everyone with the resources to put any of that into production has datasets that don't fit on a single drive. So there's less utility in having the drive speaking proper SQL, but a lot of active research into how to usefully offload some of the DB work onto compute resources that reside on the SSD itself.

(Also, microcontroller is a bit odd to use to refer to the main controller chip inside a SSD, especially a high-end enterprise SSD. It gives a completely misleading indication of scale.)

inbx0• 6 years ago

Google has a project called Lovefield [1] that is a SQL-like thing on top of IndexedDB. Not exactly SQLite and I'm not sure what its status is now but might be of interest.

[1] https://github.com/google/lovefield

antimatter15• 6 years ago

I've actually prototyped this recently, but never got around to packaging it up into a library.

There are a few neat adjacent things that it can be used for (e.g. opening big SQLite files on disk without reading it all to memory), building something like Datasette (https://github.com/simonw/datasette) that can run queries on data hosted as static files, or for (as you suggested) using SQLite in a browser with persistence.

For that particular use case, there's a bit of complexity related to mutexes and stuff in trying to prevent simultaneous browser tabs doing write operations from corrupting the database.

saurik• 6 years ago

What you really want for this is SQLite4--which added an abstraction layer below the database and above the VFS which could use a key-value store--but sadly I think it ended up being scrapped :(.

https://sqlite.org/src4/doc/trunk/www/design.wiki

dzonga• 6 years ago

don't know if I'm remembering correctly, wasn't there an sql interface in browsers once before, then it got gutted ?

CarelessExpert• 6 years ago

Yup: https://en.wikipedia.org/wiki/Web_SQL_Database

peterburkimsher• 6 years ago

I'm using SQL.js and it's great!

A few weeks ago, I built a program to help find jobs in New Zealand and Australia. It scrapes the Seek website, and allows me to make more complex queries (e.g. does not contain "right to live and work in this location")

https://ifeelseek.github.io/

Currently I'm running the scraper on a spare laptop manually every day or two. I'd rather set it up to work with Github Actions, but didn't get around to that yet.

bobochan• 6 years ago

Very cool. I use it to teach SQL. I added a CodeMirror region for editing SQL code and have buttons that load a few example databases. The advantage of this is that students do not have to install anything, they can just visit the web site, and they can practice destructive steps like deleting rows or a table, and then just reset everything with a button click. Discovering SQL.js was a huge moment.

bstar77• 6 years ago

I've had so many problems compiling the sql driver for Electron. I will definitely be giving this a try.

malkia• 6 years ago

Another user of sqlite in the browser (WebAssembly) is the Perfetto UI (for visualizating tracing data - e.g. the chrome://tracing format + others) - https://github.com/google/perfetto/blob/master/docs/README.m...

gary_bernhardt• 6 years ago

We use SQL.js to power the SQL course at https://www.executeprogram.com. We've encountered a couple of relatively minor hiccups, but overall it's been great. We've had thousands of users go through that course with no reported problems that are attributable to SQL.js.

singularity2001• 6 years ago

what happened to the pure web assembly port https://github.com/ryan-codingintrigue/sql-wasm ? How does it compare?

atmin• 6 years ago

sql.js does this

sql.js uses emscripten to compile SQLite to webassembly (or to javascript code for compatibility with older browsers)
By default, sql.js uses wasm

SQL.js: SQLite Compiled to JavaScript

Related Stories