Simon Willison’s Weblog

Blogmarks tagged sqlite

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Spatialite Speed Test. Part of an excellent series of posts about SpatiaLite from 2012—here John C. Zastrow reports on running polygon intersection queries against a 1.9GB database file in 40 seconds without an index and 0.186 seconds using the SpatialIndex virtual table mechanism. # 4th April 2021, 4:28 pm

sqlite-plus (via) Anton Zhiyanov bundled together a bunch of useful SQLite C extensions for things like statistical functions, unicode string normalization and handling CSV files as virtual tables. The GitHub Actions workflow here is a particularly useful example of compiling SQLite extensions for three different platforms. # 25th March 2021, 9:13 pm

logpaste (via) Useful example of how to use the Litestream SQLite replication tool in a Dockerized application: S3 credentials are passed to the container on startup, it then attempts to restore the SQLite database from S3 and starts a Litestream process in the same container to periodically synchronize changes back up to the S3 bucket. # 17th March 2021, 3:48 pm

sqlite-uuid (via) Another Python package that wraps a SQLite module written in C: this one provides access to UUID functions as SQLite functions. # 15th March 2021, 2:55 am

sqlite-spellfix (via) I really like this pattern: “pip install sqlite-spellfix” gets you a Python module which includes a compiled (on your system when pip install ran) copy of the SQLite spellfix1 module, plus a utility variable containing its path so you can easily load it into a SQLite connection. # 15th March 2021, 2:52 am

Fuzzy Name Matching in Postgres. Paul Ramsey describes how to implement fuzzy name matching in PostgreSQL using the fuzzystrmatch extension and its levenshtein() and soundex() functions, plus functional indexes to query against indexed soundex first and then apply slower Levenshtein. The same tricks should also work against SQLite using the datasette-jellyfish plugin. # 22nd February 2021, 9:16 pm

Why I Built Litestream. Litestream is a really exciting new piece of technology by Ben Johnson, who previously built BoltDB, the key-value store written in Go that is used by etcd. It adds replication to SQLite by running a process that converts the SQLite WAL log into a stream that can be saved to another folder or pushed to S3. The S3 option is particularly exciting—Ben estimates that keeping a full point-in-time recovery log of a high write SQLite database should cost in the order of a few dollars a month. I think this could greatly expand the set of use-cases for which SQLite is sensible choice. # 11th February 2021, 7:25 pm

sqlite-utils 3.2 (via) As discussed in my weeknotes yesterday, this is the release of sqlite-utils that adds the new “cached table counts via triggers” mechanism. # 3rd January 2021, 9:25 pm

Replicating SQLite with rqlite (via) I’ve been trying out rqlite, a “lightweight, distributed relational database, which uses SQLite as its storage engine”. It’s written in Go and uses the Raft consensus algorithm to allow a cluster of nodes to elect a leader and replicate SQLite statements between them. By default it uses in-memory SQLite databases with an on-disk Raft replication log—here are my notes on running it in “on disk” mode as a way to run multiple Datasette processes against replicated SQLite database files. # 28th December 2020, 7:51 pm

CG-SQL (via) This is the toolkit the Facebook Messenger team wrote to bring stored procedures to SQLite. It implements a custom version of the T-SQL language which it uses to generate C code that can then be compiled into a SQLite module. # 22nd October 2020, 6:25 pm

Project LightSpeed: Rewriting the Messenger codebase for a faster, smaller, and simpler messaging app (via) Facebook rewrote their iOS messaging app earlier this year, dropping it from 1.7m lines of code to 360,000 and reducing the binary size to a quarter of what it was. A key part of the new app’s architecture is much heavier reliance on SQLite to coordinate data between views, and to dynamically configure how different views are displayed. They even built their own custom system to add stored procedures to SQLite so they could execute portable business logic inside the database. # 22nd October 2020, 6:22 pm

Proof of concept: sqlite_utils magic for Jupyter (via) Tony Hirst has been experimenting with building a Jupyter “magic” that adds special syntax for using sqlite-utils to insert data and run queries. Query results come back as a Pandas DataFrame, which Jupyter then displays as a table. # 21st October 2020, 5:26 pm

Pikchr. Interesting new project from SQLite creator D. Richard Hipp. Pikchr is a new mini language for describing visual diagrams, designed to be embedded in Markdown documentation. It’s already enabled for the SQLite forum. Implementation is a no-dependencies C library and output is SVG. # 21st October 2020, 4:02 pm

evernote-to-sqlite (via) The latest tool in my Dogsheep series of utilities for personal analytics: evernote-to-sqlite takes Evernote note exports en their ENEX XML format and loads them into a SQLite database. Embedded images are loaded into a BLOB column and the output of their cloud-based OCR system is added to a full-text search index. Notes have a latitude and longitude which means you can visualize your notes on a map using Datasette and datasette-cluster-map. # 12th October 2020, 12:38 am

Datasette Weekly: Datasette 0.50, git scraping, extracting columns (via) The first edition of the new Datasette Weekly newsletter—covering Datasette 0.50, Git scraping, extracting columns with sqlite-utils and featuring datasette-graphql as the first “plugin of the week” # 10th October 2020, 9 pm

Bedrock: The SQLitening (via) Back in March 2018 switched over to running on Django using SQLite! They’re using the same pattern I’ve been exploring with Datasette: their SQLite database is treated as a read-only cache by their frontend servers, and a new SQLite database is built by a separate process and fetched onto the frontend machines every five minutes by a scheduled task. They have a healthcheck page which shows the latest version of the database and when it was fetched, and even lets you download the 25MB SQLite database directly (I’ve been exploring it using Datasette). # 7th October 2020, 11:47 pm

DuckDB (via) This is a really interesting, relatively new database. It’s kind of a weird hybrid between SQLite and PostgreSQL: it uses the PostgreSQL parser but models itself after SQLite in that databases are a single file and the code is designed for use as an embedded library, distributed in a single amalgamation C++ file (SQLite uses a C amalgamation). It features a “columnar-vectorized query execution engine” inspired by MonetDB (also by the DuckDB authors) and is hence designed to run analytical queries really quickly. You can install it using “pip install duckdb”—the resulting module feels similar to Python’s sqlite3, and follows roughly the same DBAPI pattern. # 19th September 2020, 11:43 pm

sqlite-utils 2.14 (via) I finally figured out porter stemming with SQLite full-text search today—it turns out it’s as easy as adding tokenize=’porter’ to the CREATE VIRTUAL TABLE statement. So I just shipped sqlite-utils 2.14 with a tokenize= option (plus the ability to insert binary file data from stdin). # 1st August 2020, 9:19 pm

sqlite-utils 2.12 (via) I’ve been experimenting with ways of improving BLOB support in Datasette and sqlite-utils. This new version of sqlite-utils includes a “sqlite-utils insert-files” command, which can recursively crawl directories for files and add their contents to SQLite with configurable columns containing their metadata. I was inspired by Paul Ford who has been creating multi-GB SQLite databases of images and PDFs. It turns out that when disk space is cheap this is a pretty effective way of working with interesting corpuses of documents and images. # 27th July 2020, 7:36 am

sqlite-generate (via) I wrote this tool today to generate arbitrarily large SQLite databases, for testing purposes. You tell it how many tables, columns and rows you want and it will use the Faker Python library to generate random data and populate the tables with it. # 23rd June 2020, 2:19 am

Using SQL to Look Through All of Your iMessage Text Messages (via) Dan Kelch shows how to access the iMessage SQLite database at ~/Library/Messages/chat.db—it’s protected under macOS Catalina so you have to enable Full Disk Access in the privacy settings first. I usually use the macOS terminal app but I installed iTerm for this because I’d rather enable full disk access to a separate terminal program than let anything I’m running in my regular terminal take advantage of it. It worked! Now I can run “datasette ~/Library/Messages/chat.db” to browse my messages. # 22nd May 2020, 4:45 pm

hacker-news-to-sqlite (via) The latest in my Dogsheep series of tools: hacker-news-to-sqlite uses the Hacker News API to fetch your comments and submissions from Hacker News and save them to a SQLite database. # 21st March 2020, 4:27 am

geojson-to-sqlite (via) I just put out the first release of geojson-to-sqlite—a CLI tool that can convert GeoJSON files (consisting of a Feature or a set of features in a FeatureCollection) into a table in a SQLite database. If you use the --spatialite option it will initalize the table with SpatiaLite and store the geometries in a spacially indexed geometry field—without that option it stores them as GeoJSON. # 31st January 2020, 6:40 am

Generated Columns in SQLite (via) SQLite 3.31.0 released today, and generated columns are the single most notable new feature. PostgreSQL 12 added these in October 2019, and MySQL has had them since 5.7 in October 2015. MySQL and SQLite both offer either “stored” or “virtual” generated columns, with virtual columns being calculated at runtime. PostgreSQL currently only supports stored columns. # 24th January 2020, 4:20 am

Serving 100µs reads with 100% availability (via) Fascinating use-case for SQLite from Segment: they needed a massively replicated configuration database across all of their instances that process streaming data. They chose to make the configuration available as a ~50GB SQLite database file mirrored to every instance, meaning lookups against that data could complete in microseconds. Changes to the central MySQL configuration store are pulled every 2-3 seconds, resulting in a trade-off of consistency for availability which fits their use-case just fine. # 10th January 2020, 5:15 am

athena-sqlite (via) Amazon Athena is the AWS tool for querying data stored in S3—as CSV, JSON or Apache Parquet files—using SQL. It’s an interesting way of buliding a very cheap data warehouse on top of S3 without having to run any additional services. Athena recently added a query federation SDK which lets you define additional custom data sources using Lambda functions. Damon Cortesi used this to write a custom connector for SQLite, which lets you run queries against data stored in SQLite files that you have uploaded to S3. You can then run joins between that data and other Athena sources. # 18th December 2019, 9:05 am

sqlite-transform. I released a new CLI tool today: sqlite-transform, which lets you run “transformations” against a SQLite database. I built it out of frustration of constantly running into CSV files that use horrible American date formatting—the “sqlite-transform parsedatetime my.db mytable col1” command runs dateutil’s parser against those columns and replaces them with a nice, sortable ISO formatted timestamp. I’ve also added a “sqlite-transform lambda” command that lets you specify Python code directly on the command-line that should be used to transform every value in a specified column. # 4th November 2019, 2:41 am

goodreads-to-sqlite (via) This is so cool! Tobias Kunze built a Python CLI tool to import your Goodreads data into a SQLite database, inspired by github-to-sqlite and my various other Dogsheep tools. It’s the first Dogsheep style tool I’ve seen that wasn’t built by me—and Tobias’ write-up includes some neat examples of queries you can run against your Goodreads data. I’ve now started using Goodreads and I’m importing my books into my own private Dogsheep Datasette instance. # 14th October 2019, 4:07 am

SQL Murder Mystery in Datasette (via) “A crime has taken place and the detective needs your help. The detective gave you the  crime scene report, but you somehow lost it. You vaguely remember that the crime  was a murder that occurred sometime on ​Jan.15, 2018 and that it took place in SQL  City. Start by retrieving the corresponding crime scene report from the police  department’s database.”—Really fun game to help exercise your skills with SQL by the NU Knight Lab. I loaded their SQLite database into Datasette so you can play in your browser. # 7th October 2019, 11:37 pm

genome-to-sqlite. I just found out 23andMe let you export your genome as a zipped TSV file, so I wrote a little Python command-line tool to import it into a SQLite database. # 19th September 2019, 3:58 pm