现代化内存存储：用于替代Redis和Memcached 它提供了高性能和可扩展的内存存储解决方案，适用于各种应用场景

<p align="center"> <a href="https://dragonflydb.io"> <img src="/.github/images/logo-full.svg" width="284" border="0" alt="Dragonfly"> </a> </p> [](https://github.com/dragonflydb/dragonfly/actions/workflows/ci.yml) [](https://twitter.com/dragonflydbio) Other languages: [简体中文](README.zh-CN.md) [日本語](README.ja-JP.md) [한국어](README.ko-KR.md) [Website](https://www.dragonflydb.io/) • [Docs](https://dragonflydb.io/docs) • [Quick Start](https://www.dragonflydb.io/docs/getting-started) • [Community Discord](https://discord.gg/HsPjXGVH85) • [GitHub Discussions](https://github.com/dragonflydb/dragonfly/discussions) | [GitHub Issues](https://github.com/dragonflydb/dragonfly/issues) | [Contributing](https://github.com/dragonflydb/dragonfly/blob/main/CONTRIBUTING.md)| [Dragonfly Cloud](https://www.dragonflydb.io/cloud) ## The world's most efficient in-memory data store Dragonfly is an in-memory data store built for modern application workloads. Fully compatible with Redis and Memcached APIs, Dragonfly requires no code changes to adopt. Compared to legacy in-memory datastores, Dragonfly delivers 25X more throughput, higher cache hit rates with lower tail latency, and can run on up to 80% less resources for the same sized workload. ## Contents - [Benchmarks](#benchmarks) - [Quick start](https://github.com/dragonflydb/dragonfly/tree/main/docs/quick-start) - [Configuration](#configuration) - [Roadmap and status](#roadmap-status) - [Design decisions](#design-decisions) - [Background](#background) ## <a name="benchmarks"><a/>Benchmarks We first compare Dragonfly with Redis on `m5.large` instance which is commonly used to run Redis due to its single-threaded architecture. The benchmark program runs from another load-test instance (c5n) in the same AZ using `memtier_benchmark -c 20 --test-time 100 -t 4 -d 256 --distinct-client-seed` Dragonfly shows a comparable performance: 1. SETs (`--ratio 1:0`): | Redis | DF | | -----------------------------------------|----------------------------------------| | QPS: 159K, P99.9: 1.16ms, P99: 0.82ms | QPS:173K, P99.9: 1.26ms, P99: 0.9ms | | | | 2. GETs (`--ratio 0:1`): | Redis | DF | | ----------------------------------------|----------------------------------------| | QPS: 194K, P99.9: 0.8ms, P99: 0.65ms | QPS: 191K, P99.9: 0.95ms, P99: 0.8ms | The benchmark above shows that the algorithmic layer inside DF that allows it to scale vertically does not take a large toll when running single-threaded. However, if we take a bit stronger instance (m5.xlarge), the gap between DF and Redis starts growing. (`memtier_benchmark -c 20 --test-time 100 -t 6 -d 256 --distinct-client-seed`): 1. SETs (`--ratio 1:0`): | Redis | DF | | ----------------------------------------|----------------------------------------| | QPS: 190K, P99.9: 2.45ms, P99: 0.97ms | QPS: 279K , P99.9: 1.95ms, P99: 1.48 | 2. GETs (`--ratio 0:1`): | Redis | DF | | ----------------------------------------|----------------------------------------| | QPS: 220K, P99.9: 0.98ms , P99: 0.8ms | QPS: 305K, P99.9: 1.03ms, P99: 0.87ms | Dragonfly throughput capacity continues to grow with instance size, while single-threaded Redis is bottlenecked on CPU and reaches local maxima in terms of performance. <img src="http://static.dragonflydb.io/repo-assets/aws-throughput.svg" width="80%" border="0"/> If we compare Dragonfly and Redis on the most network-capable instance c6gn.16xlarge, Dragonfly showed a 25X increase in throughput compared to Redis single process, crossing 3.8M QPS. Dragonfly's 99th percentile latency metrics at its peak throughput: | op | r6g | c6gn | c7g | |-------|-------|-------|-------| | set | 0.8ms | 1ms | 1ms | | get | 0.9ms | 0.9ms | 0.8ms | | setex | 0.9ms | 1.1ms | 1.3ms | *All benchmarks were performed using `memtier_benchmark` (see below) with number of threads tuned per server and instance type. `memtier` was run on a separate c6gn.16xlarge machine. We set the expiry time to 500 for the SETEX benchmark to ensure it would survive the end of the test.* ```bash memtier_benchmark --ratio ... -t <threads> -c 30 -n 200000 --distinct-client-seed -d 256 \ --expiry-range=... ``` In pipeline mode `--pipeline=30`, Dragonfly reaches **10M QPS** for SET and **15M QPS** for GET operations. ### Dragonfly vs. Memcached We compared Dragonfly with Memcached on a c6gn.16xlarge instance on AWS. With a comparable latency, Dragonfly throughput outperformed Memcached throughput in both write and read workloads. Dragonfly demonstrated better latency in write workloads due to contention on the [write path in Memcached](docs/memcached_benchmark.md). #### SET benchmark | Server | QPS(thousands qps) | latency 99% | 99.9% | |:---------:|:------------------:|:-----------:|:-------:| | Dragonfly | 🟩 3844 |🟩 0.9ms | 🟩 2.4ms | | Memcached | 806 | 1.6ms | 3.2ms | #### GET benchmark | Server | QPS(thousands qps) | latency 99% | 99.9% | |-----------|:------------------:|:-----------:|:-------:| | Dragonfly | 🟩 3717 | 1ms | 2.4ms | | Memcached | 2100 | 🟩 0.34ms | 🟩 0.6ms | Memcached exhibited lower latency for the read benchmark, but also lower throughput. ### Memory efficiency To test memory efficiency, we filled Dragonfly and Redis with ~5GB of data using the `debug populate 5000000 key 1024` command, sent update traffic with `memtier`, and kicked off the snapshotting with the `bgsave` command. This figure demonstrates how each server behaved in terms of memory efficiency. <img src="http://static.dragonflydb.io/repo-assets/bgsave-memusage.svg" width="70%" border="0"/> Dragonfly was 30% more memory efficient than Redis in the idle state and did not show any visible increase in memory use during the snapshot phase. At peak, Redis memory use increased to almost 3X that of Dragonfly. Dragonfly finished the snapshot faster, within a few seconds. For more info about memory efficiency in Dragonfly, see our [Dashtable doc](/docs/dashtable.md). ## <a name="configuration"><a/>Configuration Dragonfly supports common Redis arguments where applicable. For example, you can run: `dragonfly --requirepass=foo --bind localhost`. Dragonfly currently supports the following Redis-specific arguments: * `port`: Redis connection port (`default: 6379`). * `bind`: Use `localhost` to only allow localhost connections or a public IP address to allow connections **to that IP** address (i.e. from outside too). Use `0.0.0.0` to allow all IPv4. * `requirepass`: The password for AUTH authentication (`default: ""`). * `maxmemory`: Limit on maximum memory (in human-readable bytes) used by the database (`default: 0`). A `maxmemory` value of `0` means the program will automatically determine its maximum memory usage. * `dir`: Dragonfly Docker uses the `/data` folder for snapshotting by default, the CLI uses `""`. You can use the `-v` Docker option to map it to your host folder. * `dbfilename`: The filename to save and load the database (`default: dump`). There are also some Dragonfly-specific arguments: * `memcached_port`: The port to enable Memcached-compatible API on (`default: disabled`). * `keys_output_limit`: Maximum number of returned keys in `keys` command (`default: 8192`). Note that `keys` is a dangerous command. We truncate its result to avoid a blowup in memory