MemSharp 1.0.0

MemSharp

A fast, embeddable in-memory database for .NET. Sharded key/value storage with seven value types, TTLs, pub/sub, a SQL-like keyspace query layer, snapshot and append-only persistence, and a RESP server — with no package dependencies at all.

By Gravicode Studios, led by Kang Fadhil.

dotnet add package MemSharp

Embedded

using MemSharp;

using var db = new MemDb();

db.Set("symbol:BTC", "68350.25");
db.Set("session:9f2", "kang", TimeSpan.FromMinutes(30));

db.SortedSetAdd("book:BTC:bids", "bid-1", 68_349.75);
var best = db.SortedSetRangeByRank("book:BTC:bids", 0, 9, descending: true);

db.StreamAdd("trades", ["symbol", "BTC", "qty", "0.5"], maxLength: 100_000);
db.TimeSeriesAdd("px:BTC", 68_350.25);

Query the keyspace

One table, keys, whose rows are your keys — with key, type, size, ttl and value columns.

var big = db.ExecuteSql(
    "SELECT key, size FROM keys WHERE key LIKE 'order:%' AND size > 100 ORDER BY size DESC LIMIT 10");

// or LINQ, straight over memory
var expiring = db.Query()
    .Where(k => k.ExpiresAt is not null)
    .OrderBy(k => k.ExpiresAt)
    .Take(20);

Persistence

Snapshots and an append-only log compose: the snapshot is the base image, the log covers everything written since.

using var db = new MemDb(new MemDbOptions
{
    // Snapshot on a timer and after a write threshold, plus a log for crash durability.
    Persistence = PersistenceOptions.Durable("trading.msnap"),
});

db.Save();                 // one-time, synchronous
await db.SaveAsync();      // in the background

PersistenceOptions.ManualSnapshot(path) saves only when asked; PersistenceOptions.AutomaticSnapshot(path) saves on a schedule; the default is memory-only.

Serve it over TCP

The wire protocol is RESP2, so redis-cli and the standard Redis client libraries work for the commands MemSharp implements. Official clients for Python, Go and Node.js ship in the repository.

using var db = new MemDb();
await using var server = new MemServer(db, new MemServerOptions { Port = 6380 });
await server.StartAsync();

MemSharp has no authentication, so the server binds loopback by default. Binding beyond it is a deliberate act.

Command-line tools

dotnet tool install -g MemSharp.Cli

memsharp repl                          # interactive shell
memsharp serve --data trading.msnap    # host a server
memsharp bench                         # throughput and latency percentiles
memsharp demo                          # guided tour, with the code for each result

Performance, and how it compares to Redis

Measured with redis-benchmark — Redis's own C client — driving both servers on one machine. MemSharp speaks RESP2, so redis-cli and redis-benchmark work against it unmodified.

Redis is 1.2-1.65x faster on single-command round-trips; MemSharp is 1.05-1.28x faster pipelined. Embedded there is no comparison to make, and that is the point: Redis is a mature, clustered, authenticated server and MemSharp does not replace it. If you talk to a database over a network, use Redis. Use MemSharp to put a fast, typed, queryable store inside a .NET process.

Full tables and methodology are in the repository.

Value types

Documentation

Full documentation, benchmark figures and an Avalonia trading demo are in the repository.

MIT licensed.