A client api to Sonnerie, a timeseries database


Keywords
database, protocol, timeseries, cli, rust, timeseries-database
License
BSD-2-Clause

Documentation

GitHub license Crates.io

NEWS: 2019-12-23: 0.5 is a total rewrite!

Introduction

Sonnerie is a time-series database. Map a timestamp to a floating-point value. Store multiple of these series in a single database. Insert tens of millions of samples in minutes, on rotational media or solid-state.

Sonnerie is optimized for storing data that comes in as many values over many series, and for reading one series at a time. It is also very good at dumping lexicographically sequential series (which means: everything).

It achieves this by storing each transaction in a single file. After the transaction is completed, it is fsynced then made available for reading.

Features

  • A straight-forward protocol for reading and writing
  • Easy setup: insert data on the command line.
  • No query language
  • Transactional: a transaction is completely committed or not at all.
  • Isolated: A transaction doesn't see updates from other transactions or expose its changes until it has been committed.
  • Durable: committed data is resistant to loss from unexpected shutdown.
  • Nanosecond-resolution timestamps (64 bit), 1970-2554
  • No weird dependencies, no virtual machines, one single native binary for the command line tool
  • floating point and integer values, multiple columns per sample

Sonnerie runs on Unix-like systems and is developed on Linux.

Quick Start

Install

Sonnerie is implemented in Rust, a systems programming language that runs blazingly fast. Installation from source therefor requires you to install the rust compiler, which is as simple as: curl https://sh.rustup.rs -sSf | sh.

Sonnerie can then be installed from Cargo: cargo install sonnerie.

Sonnerie consists of one executable, sonnerie (~/.cargo/bin/sonnerie)

Create a database

Create a database by creating a directory and an empty file named "main":

mkdir database
touch database/main

Insert data

echo -e "\
fibonacci 2020-01-01T00:00:00 1
fibonacci 2020-01-02T00:00:00 1
fibonacci 2020-01-03T00:00:00 2
fibonacci 2020-01-04T00:00:00 3
fibonacci 2020-01-05T00:00:00 5
fibonacci 2020-01-06T00:00:00 8" \
| sonnerie -d database/ add --format u --timestamp-format=%FT%T

If the "add" command succeeds, then the transaction is committed to disk.

Items added with sonnerie add must be sorted lexicographically by their key and then chronologically. This requirement does not exist in sonnerie-serve.

Read the data back

sonnerie -d database/ read %

(The % is a wildcard as is used in "LIKE" in SQL and filters on the key. Searching based on a prefix is very efficient:

sonnerie -d database/ read fib%

Sonnerie outputs the matched values:

fibonacci 2020-01-01 00:00:00     1
fibonacci 2020-01-02 00:00:00     1
fibonacci 2020-01-03 00:00:00     2
fibonacci 2020-01-04 00:00:00     3
fibonacci 2020-01-05 00:00:00     5
fibonacci 2020-01-06 00:00:00     8

Usage

Row format

Each series has a format. The format is specified as a bunch of single character codes, one for each value.

The character codes are:

  • f - a 32 bit float (f32)
  • F - a 64 bit float (f64)
  • u - a 32 bit unsigned integer (u32)
  • U - a 64 bit unsigned integer (u64)
  • i - a 32 bit signed integer (i32)
  • I - a 64 bit signed integer (i64)

In the above "fibonacci" example, we're using the "u" format.

Multi-column rows are not extensively tested, but would look something like this, for two floating point values representing latitude and longitude:

oceanic-airlines 2018-01-01T00:00:00 ff 37.686751 -122.602227
oceanic-airlines 2018-01-01T00:00:01 ff 37.686810 -122.603713
oceanic-airlines 2018-01-01T00:00:02 ff 37.686873 -122.605997
oceanic-airlines 2018-01-01T00:00:03 ff 37.687022 -122.609997
oceanic-airlines 2018-01-01T00:00:04 ff 37.687364 -122.610945
oceanic-airlines 2018-01-01T00:00:05 ff 37.687503 -122.615211

Checked mode is slow

The command line tools by default use a safe "checked" mode, in which new rows' format must be the same as the existing format for their key. This has a significant (10x) performance penalty, so you can turn it off with the --unsafe-unchecked option. The HTTP server is always unsafe and fast.

No server is necessary

All actions can be done by running sonnerie -d /path/to/data/. Furthermore, a file, (after it gets its ".tmp" suffix removed) will never change, though the file named main will get replaced sometimes. This means you can replicate a database by hardlinking all the files (ln).

The database must be compacted

On a regular (possibly daily) basis, you must compact the database. This rolls a bunch of transaction files into a single large transaction file. This is important for performance. By the time about 100 transaction files are present, performance suffers greatly. Therefor, compact the database at approximately the rate necessary to prevent that.

There are two types of compactions, a major and a minor one. A major one replaces the entire database, which requires reading and rewriting the entire database. A minor one replaces all of the transaction files with a single new transaction file. This is a lot faster because it requires only reading and rewriting the contents the transaction files and not the main file.

A major compaction is accomplished with:

sonnerie -d /path/to/data/ compact --major

And a minor compaction:

sonnerie -d /path/to/data/ compact

Compacting doesn't block readers or writers, but only one can happen at any given moment, so a lock is placed to prevent multiple concurrent compactions.

Compactions are atomic, so you can cancel it (with ^C) at any time.

You can compact and filter

In case some data in the database needs to be removed, you can use compact with the --gegnum option. Gegnum means "through" in Icelandic.

This command removes records that start with bad-objects:

compact --major --gegnum 'grep -v ^bad-objects'

Do a normal compaction, but also count records:

compact --major --gegnum 'pv -l'

The --gegnum runs its command inside a /bin/sh, so pipelines work. Filter out bad objects AND modify the names of other objects:

compact --major --gegnum 'grep -v ^bad-objects | sed "s/^old-name/new-name/"'

You can also see a preview of its output by piping your command into | tee /dev/stderr.

Note that the rows come as "key\ttimestamp\tformat\tvalue"

By default, gegnum compactions run in a "safe" mode. This is safer but very slow, as each key must be verified on insertion to make sure the datatypes are homogenous. Use the --unsafe-nocheck option to disable the feature.

You can also "read | filter | add" into a different database, but gegnum allows you to modify an existing database which is useful for online maintenance on a database that gets concurrent updates.

sonnerie-serve

A server is provided so that you can conveniently read and write to the database via HTTP.

Run sonnerie-serve -d /path/to/database/ -l 0.0.0.0:5555 and then you may make PUT and GET requests:

  • Read the named series:

    curl http://localhost:5555/fibonacci

  • Read series by wildcard:

    curl http://localhost:5555/fib%

  • Output human-readable timestamps:

    curl http://localhost:5555/fib%?human

  • Add more data:

    curl -X PUT http://localhost:5555/ --data-binary 'fibonacci 2020-01-07T00:00:00 u 13'

(200 OK means that the transaction was committed)

Unlike sonnerie add, sonnerie-serve allows unsorted input.

Note that because sonnerie mmaps its files, sonnerie-serve will show huge values for its virtual memory usage (VIRT in top), but actual memory utilization will be reasonable.

You may continue to read and modify your sonnerie database by the command line or even via another concurrently-running sonnerie-serves.

sonnerie-serve is always "unsafe unchecked", meaning that if the format you specify is not the same as the existing value for that key, you will get corruptions.

An alternate approach is to use "sshfs" to mount the database remotely. This approach is very performant because only compressed data goes through the network and the server doesn't need to do any of the decompressing. Avoid nfs because compactions will cause files to get deleted, and then the client will get an IO error, as NFS cannot track files that are closed on the server.

Sonnerie's API

Sonnerie can be used as a Rust library so you can read and write databases directly, but the API is incomplete and poorly documented, for now.

Sonnerie is used in production

Sonnerie is used by e.ventures Management LLC with a >100GiB database and 10s of billions of rows.

Performance

An approximate average lookup time for a random key is around 100ms on an SSD and much slower on a busy rotational media device. Sequential access (i.e., reading the whole database in lexicographical order) is somewhere around 2k keys/sec and 1M records/sec, very much depending on the data itself.

Copyright

Sonnerie was implemented by Charles Samuels at e.ventures Management LLC.