SQLite File Format Viewer

SQLite File Format Viewer(sqlite-internal.pages.dev)

273 points by ilumanty 1 year ago | 41 comments

jchw 1 year ago |

This really would've come in handy when I was debugging my own SQLite parser a couple weeks ago.

One thing that initially confused me was how exactly the pages worked w.r.t. the first page on disk... I misunderstood the SQLite documentation in different ways, but it's really rather simple: the very first page is just treated as containing the file header in it, and it pushes down the rest of the data, making the page shorter than the other pages. You can see that illustrated clearly if you click into the first page of a database using this tool: the database header comes first, then the page header.

This tool will undoubtedly come in handy for anyone who has a reason to be dealing with SQLite data structures directly for whatever reason, especially since the SQLite documentation is a bit terse at times.

burntcaramel 1 year ago | |

Yes I’m also working on a SQLite parser, mine is in raw WebAssembly. Is yours open source too? This tool will be so useful. I have basic page reading and parsing of the CREATE TABLE schema: https://github.com/RoyalIcing/SilverOrb/blob/9dacad0ce521b0d...

My plan is to create a miniature .wasm module to read .sqlite files that works in the browser. It will be in the tens of kilobytes rather than the 1 megabyte that the official fantastic sqlite.wasm is. The reduced download means even on 3G you ought to be able to load within a few seconds. You can use SQLite files as your network payloads then, and perhaps even as the working mutable state synced between server and clients.

jchw 1 year ago | | |

Mine is in TypeScript and for the purpose of parsing a file that happens to use sqlite, so I don't think I'll bother parsing the CREATE TABLE schema unless I have to. It's not currently posted anywhere but will be open source. It works, but the code isn't particularly great :)

hinkley 1 year ago | |

I really want a data format that is effectively binary JSON. What is the subset of all of the features of SQLite that makes either a read-only or an updatable data set that is compact. But better searchability than a streaming parser.

jchw 1 year ago | | |

If you want to maintain the properties that SQLite has for read use cases, you'll need to replicate a couple of features. At the very least, you'll probably want the format to still be page-based with a BTree structure. You really could get away with just using the SQLite format if you didn't mind the weirdness; a functional SQLite parser that can read tables would not be a significant amount of code. I think, though, that if you want to read the schema as SQLite understands it, you'd need to interpret the CREATE TABLE syntax, which would make it a bit more complex for sure. Otherwise, you can read tables and columns themselves relatively easily, and the values are all stringified.

79a6ed87 1 year ago | | |

Have you tried MessagePack[0]?

0: https://msgpack.org/index.html

cwmma 1 year ago | | |

Parquet or some other column oriented data format is probably closest to what you want without getting into indexing your flat files or similar

Retr0id 1 year ago | | |

sqlite itself supports a binary encoding of JSON: https://sqlite.org/jsonb.html

w10-1 1 year ago | | |

MongoDB's BSON?

invisal 1 year ago | |

Glad you like it.

latexr 1 year ago |

I especially like that it provides a sample database. Would be nice it were downloadable as a file, so we could explore it with our own tools as well and get a better feeling for how the tool works.

TheRealPomax 1 year ago | |

https://github.com/invisal/sqlite-internal/tree/main/public, or just download it by copying the URL from your network tab when you load it.

roelschroeven 1 year ago |

I tried with a simple database, and it just shows me a blank screen. The console in developer tools shows an exception (both in Firefox and Chromium):

    index-CGfYebmt.js:85 Uncaught RangeError: Offset is outside the bounds of the DataView
        at DataView.prototype.getUint32 (<anonymous>)
        at R0 (index-CGfYebmt.js:85:4683)
        at X0 (index-CGfYebmt.js:85:7966)
        at index-CGfYebmt.js:85:8157
        at Array.map (<anonymous>)
        at Q0 (index-CGfYebmt.js:85:8150)
        at index-CGfYebmt.js:85:8240
        at Object.useMemo (index-CGfYebmt.js:48:46087)
        at My.$.useMemo (index-CGfYebmt.js:17:7276)
        at V0 (index-CGfYebmt.js:85:8228)
    R0 @ index-CGfYebmt.js:85
    X0 @ index-CGfYebmt.js:85
    (anonymous) @ index-CGfYebmt.js:85
    Q0 @ index-CGfYebmt.js:85
    (anonymous) @ index-CGfYebmt.js:85
    useMemo @ index-CGfYebmt.js:48
    My.$.useMemo @ index-CGfYebmt.js:17
    V0 @ index-CGfYebmt.js:85
    tc @ index-CGfYebmt.js:48
    bc @ index-CGfYebmt.js:48
    lo @ index-CGfYebmt.js:48
    No @ index-CGfYebmt.js:48
    wm @ index-CGfYebmt.js:48
    Xc @ index-CGfYebmt.js:48
    Ao @ index-CGfYebmt.js:48
    Qo @ index-CGfYebmt.js:48
    me @ index-CGfYebmt.js:25

invisal 1 year ago | |

Probably I might made mistake somewhere in my parser. Do you have small reproducible database with no sensitive database and add to the https://github.com/invisal/sqlite-internal/issues

I will try to fix it

roelschroeven 1 year ago | | |

Issue created: https://github.com/invisal/sqlite-internal/issues/3

roelschroeven 1 year ago | | |

Fixed now!

NoSalt 1 year ago |

Really nice, looks great!

However, I am not a fan of uploading databases to "strange" sites on the internet, so I will probably never use this.

hamstergene 1 year ago |

This is super cool and will really help anyone studying how to build their own storage engines.

A note: the table that describes the data structures (Field # | Description | Value) should also list the data type (uint8 uint16 int32 text etc.). If it's an enum ("Table Leaf"), reference other possible enum values. If its length depends on another field, reference that field No.

graemep 1 year ago |

Very cool.

It would be nice if it tied the format in a bit more to the schema and data being shown, but that is a very minor gripe given how nice a tool this is.

NathanFlurry 1 year ago |

I've been enjoying watching you build this on X – nice work.

invisal 1 year ago | |

Thanks so much :)

mubou 1 year ago |

This is really cool.

nraynaud 1 year ago |

this is a wonderful learning tool, thank you.

throw0101d 1 year ago |

Meta: always found it interesting that .dev was allowed to be a TLD:

* https://en.wikipedia.org/wiki/.dev