josiahcarlson

"""
one_bit_difference.py

Written September / October 2023 by Josiah Carlson - josiah.carlson@gmail.com
Released into the public domain. Please include this authorship note / reference
to this GIST if you use / derive this software. Thank you.

Been thinking about this algorithm for about 17 years, haven't seen it around.
I might not know the proper literature search to find relevant references, or if
this was already done.

josiahcarlson

$ time docker-compose run redis-server numactl -N 1 -l /usr/src/redis/src/redis-benchmark --crc 512000000 --csv --combine
algorithm,buffer,performance,crc64_matches
crc_1byte,512000000,400,1
crcspeed,512000000,1354,1
crcdual,512000000,2129,1
crctri,512000000,2243,1
crc_1byte,312000000,401,1
crcspeed,312000000,1352,1
crcdual,312000000,2090,1
crctri,312000000,2213,1

josiahcarlson

'''
This this was retyped from https://www.twitch.tv/videos/459202303 for notes and
then updated by the author of rom, me, Josiah Carlson


Notes:
* For created_at, or any default, if it is "callable", it will be called at
  entity creation/instantiation. In the demo in the video, we see:
    created_at = rom.DateTime(default=datetime.datetime.now())

josiahcarlson

This is my reply to Alex Mills: http://www.binpress.com/tutorial/introduction-to-rate-limiting-with-redis/155

Yes, with threads, processes, or an async reactor. That said...

$ redis-benchmark -n 2000000 -c 20 -q
[snip]
SET: 115141.05 requests per second
GET: 134048.27 requests per second
INCR: 180505.41 requests per second
LPUSH: 176056.33 requests per second

josiahcarlson

-- keys: key dest
-- argv: score member [score member ...]
-- e.g. keys: "data:test:1:2" "data-sum:test:1:2"
--      argv: 10 a 15 b
 
local key = KEYS[1]
local dest = KEYS[2]
local sum = tonumber(redis.call('get', dest)) or 0
 
for i=1, #ARGV, 2 do

josiahcarlson

'''
Released into the public domain.

This code will append 2 bytes to the end of a key to force the key to a specific Redis slot.
'''


from collections import defaultdict
from itertools import imap
import struct

josiahcarlson

'''
rate_limit2.py

Copyright 2014, Josiah Carlson - josiah.carlson@gmail.com
Released under the MIT license

This module intends to show how to perform standard and sliding-window rate
limits as a companion to the two articles posted on Binpress entitled
"Introduction to rate limiting with Redis", parts 1 and 2:

josiahcarlson

'''
result_multiplex.py

Copyright 2014 Josiah Carlson
Released as LGPL 2 or 3, your choice.


Problem:
You have a task processor that writes the results of tasks to a specified key

josiahcarlson

'''
rate_limit.py

Written May 7-8, 2014 by Josiah Carlson
Released under the MIT license.

Offers a simple interface for offering rate limiting on a per second, minute,
hour, and day basis. Useful for offering varying rate limits depending on user
behavior. Sliding window based limits offer per minute, hour, and day limits

josiahcarlson

'''
follow_file.py
Written April 13, 2014 by Josiah Carlson

Released under the MIT license.

This could likely be made more efficient with the use of the pyinotify library,
and some of the module-level constants could be tuned for better performance,
depending on your platform.