alecco

from dtest import Tester, debug
from cassandra import ConsistencyLevel

class LWTExample(Tester):
    def test_lwt(self):
        cluster = self.cluster
        cluster.populate(4)
        cluster.start(wait_other_notice=True, wait_for_binary_proto=True)
        node = cluster.nodelist()[0]
        session = self.patient_cql_connection(node)

alecco

-- Note: example given is for SQLite but can be adapted to other SQL

-- This is a fast query to sample random rows
-- It gets a list of existing row identifiers (rowids),
-- materializes, sorts, and picks 10.
SELECT * FROM test
    WHERE rowid IN
        (SELECT rowid FROM test
            ORDER BY random() LIMIT 10);

alecco

# What if n nodes are assigned a random tick wait (of 1 to 10)
# to wait to become candidates when the previous leader is down?
# What is the chance of 2 candidates having the same random
# wait (birthday paradox) AND this wait to be the shortest wait.
# What's the amount of nodes with ~90% chance of dueling candidates?
# Answer: 36ish
# Based on:
# https://codecalamity.com/the-birthday-paradox-the-proof-is-in-the-python/
from random import randint
import matplotlib.pyplot as plt

alecco

# What if n nodes are assigned a random tick wait (of 1 to 10)
# to wait to become candidates when the previous leader is down?
# What is the chance of 2 candidates having the same random
# wait (birthday paradox) AND this wait to be the shortest wait.
# What's the amount of nodes with ~90% chance of dueling candidates?
# Answer: 36ish
# Based on:
# https://codecalamity.com/the-birthday-paradox-the-proof-is-in-the-python/
from random import randint
import matplotlib.pyplot as plt

alecco

# What if n nodes are assigned a random tick wait (of 1 to 10)
# to wait to become candidates when the previous leader is down?
# What is the chance of 2 candidates having the same random
# wait (birthday paradox) AND this wait to be the shortest wait.
# What's the amount of nodes with ~XX% chance of dueling candidates?
# Based on:
# https://codecalamity.com/the-birthday-paradox-the-proof-is-in-the-python/
#
# For power distribution
#

alecco

// g++ -lfmt exponential.cc -o exponential && ./exponential <lambda>
//
// Using lambda 0.3
//  01:  1% 00189 - ***
//  02:  2% 00275 - *****
//  03:  3% 00330 - ******
//  04:  4% 00430 - ********
//  05:  6% 00613 - ************
//  06:  8% 00839 - ****************
//  07: 11% 01104 - **********************

alecco

# https://www.redhat.com/sysadmin/podman-inside-container
# https://fedoramagazine.org/podman-with-capabilities-on-fedora/
# https://wiki.debian.org/CrossCompiling

# XXX need to run as root as debootstrap needs mknod privilege
sudo podman pull debian:stable-slim
sudo podman run -it --cap-add=all --privileged debian:stable-slim

# set -o vi
# cat >> /etc/apt/sources.list

alecco

cmake_minimum_required(VERSION 3.20)

project(YOUR_PROJECT_NAME LANGUAGES CXX CUDA)

# you might want C++17
set(CMAKE_CUDA_STANDARD 20)               # C++20
set(CMAKE_CUDA_STANDARD_REQUIRED ON)
set(CMAKE_CXX_EXTENSIONS OFF)
set(CMAKE_EXPORT_COMPILE_COMMANDS ON)     # generate compile_commands.json