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A redis clone in Python 3 to disprove some falsehoods about performance.


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pydis is an experiment to disprove some of the falsehoods about performance and optimisation regarding software and interpreted languages in particular.

Below you will find a Redis clone, pydis, written in ~250 lines of idiomatic Python code, providing a subset of redis' functionality for which there are official benchmarks.

Briefly, pydis is ~50% as fast as Redis measured in number operations per second.

P.S. This is not a criticism of Redis, which is a brilliant project and a system-level software that powers thousands of infrastructures. It just happened to be one of the fastest software I could imagine and clone the same day.


I have used the following libraries written in C for performance:

  • uvloop

    uvloop is a fast, drop-in replacement of the built-in asyncio event loop. uvloop is implemented in Cython and uses libuv under the hood. >

  • hiredis

    Python extension that wraps protocol parsing code in hiredis.



redis-benchmark -q -t set,get,incr,lpush,rpush,lpop,rpop,sadd,hset,spop,lrange,mset -n 100000 -P 5 
  • 100,000 requests in total per command.
  • Requests are pipelined in groups of 5.

The Bar Graph

Benchmark pydis redis Ratio
SET 271,947 467,361 0.582
GET 274,283 467,237 0.587
INCR 213,409 478,669 0.446
LPUSH 216,082 381,033 0.567
RPUSH 231,143 399,238 0.579
LPOP 248,527 384,332 0.647
RPOP 241,144 429,971 0.561
SADD 219,475 434,257 0.505
HSET 220,178 377,637 0.583
SPOP 288,068 477,705 0.603
LRANGE (100) 26,170 96,254 0.272
LRANGE (300) 9,163 24,768 0.370
LRANGE (500) 5,771 19,351 0.298
LRANGE (600) 4,705 13,869 0.339
MSET 125,215 195,121 0.642

Host System

  • Ubuntu 20.04
  • Python 3.8.5 (GCC 9.3.0)
  • Redis 5.0.7 malloc=jemalloc-5.2.1 bits=64 build=636cde3b5c7a3923


Contributions are very welcome, given that they fall into one of the following categories:

  • Those that improve the performance.
    • The aim of this exercise is to prove that interpreted languages can be just as fast as C. So whilst using a faster parser in C with Python bindings is okay, rewriting pydis in Cython is not.
    • I will accept "minor" deviations from idioms only if the performance gains are worth it; stick to idiomatic Python otherwise!
  • Those to achieve feature parity with Redis for which there are official benchmarks.
    • We are not trying to develop a full-featured Redis clone here so please do not implement commands for which there are no official benchmarks.
  • Those that fix formatting etc.
    • Please do not invent your own style, use PEP 8.


A redis clone in Python 3 to disprove some falsehoods about performance.








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