matanper

import boto3
import os
import time
from subprocess import Popen, PIPE
import pyarrow.parquet as pq
import pickle
import hashlib


TSDB_CPUS = 8

cevian

CREATE EXTENSION IF NOT EXISTS "uuid-ossp";
CREATE EXTENSION IF NOT EXISTS timescaledb CASCADE;

CREATE OR REPLACE FUNCTION uuid_timestamp(uuid UUID) RETURNS TIMESTAMPTZ AS $$
DECLARE
  bytes bytea;
BEGIN
  bytes := uuid_send(uuid);
  if  (get_byte(bytes, 6) >> 4)::int2 != 1 then
    RAISE EXCEPTION 'UUID version is not 1';

cpursley

PostgreSQL is Enough

• Simplify: move code into database functions
• Just Use Postgres for Everything
• PostgreSQL is the worlds’ best database
• Postgres is eating the database world
• Hacker News discussion

Background and Cron Jobs

fxi

use_bpm 30

define :chorda do |root, type|
  case type
  when "major"
    [root, root+4, root+7]
  when "minor"
    [root, root+3, root+7]
  end
end

jonatas

-- First set the numbers of hypertables you'd like to test
\set hypertables_count 100
-- Hypertable configuration with the chunk time interval for every hypertable
\set chunk_time_interval '''1 hour'''
-- How much data you'd like to append for every append_data call
\set append_interval '''1 day'''
-- How many devices would you like to simulate in parallel
\set number_of_devices '''1'''
-- When the data starts
\set start_date '''2000-01-01'''

clarkbw

class ActionsHypertable < ActiveRecord::Migration[7.0]
  def change
    @table_name = 'actions'
    @time_column = 'created_at'
    reversible do |dir|
      dir.up do
        execute <<-SQL
          SELECT create_hypertable('#{@table_name}', '#{@time_column}', if_not_exists => TRUE, migrate_data => TRUE);
        SQL
      end

jonatas

DROP TABLE ticks CASCADE;
DROP TABLE ohlc_1s CASCADE;
CREATE TABLE ticks ( time TIMESTAMP NOT NULL, symbol varchar, price decimal, volume int);
CREATE TABLE ohlc_1s ( time TIMESTAMP NOT NULL, symbol varchar, o decimal, h decimal, l decimal, c decimal, v int);
SELECT create_hypertable('ticks', 'time');
SELECT create_hypertable('ohlc_1s', 'time');

CREATE OR REPLACE FUNCTION feed_ohlc_1s() RETURNS trigger AS
$BODY$
DECLARE

jonatas

source 'https://rubygems.org'

gem "activerecord", "~> 6.1"
gem "composite_primary_keys", "~> 6.0"
gem "pg", "~> 1.2"
gem 'pry'

tatianamac

Speaker Rider

by Tatiana Mac

Last updated 14 April 2021

What is a speaker rider?

As speaking comes with immense privilege, I have crafted a speaker rider to set expectations and boundaries around my engagement. I am grateful to all the conference organisers who have brilliantly hosted me. I would love to continue to exercise this privilege to speak at conferences, and use this privilege to make the landscape more accessible and beneficial to tech's most historically excluded and marginalised communities.

Considerations

😫 I provide a lot of explanations for those of you who never had to consider these things. Most thoughtful conferences I've attended check most of these boxes intrinsically, particularly when conference runners are experienced speakers. They get it.

patrickpissurno

-- This code is based on my other Gist "Simple linear regression in Javascript" (https://gist.github.com/patrickpissurno/ea0dc4039f075fbaf398619761bd9044)
-- There might be a more efficient way to do this in SQL

-- This function is resposible for computing the weights for the ax + b equation
CREATE OR REPLACE FUNCTION linear_regression(x_array decimal(15,2)[], y_array decimal(15,2)[]) RETURNS decimal(15,2)[] AS $$
	DECLARE
		slope decimal(15,2);
		intercept decimal(15,2);
		
		n integer;