Artem lykhvar

WAL-G PITR

This gist summarises a way to simulate point-in-time recovery (PITR) using WAL-G. Most of the material is adapted from Creston's tutorial.

Setup

First we initialize a database cluster

pg_ctl init -D cluster

How do I round to 2 decimals?

In python, you have floats and decimals that can be rounded. If you care about the accuracy of rounding, use decimal type. If you use floats, you will have issues with accuracy.

All the examples use demical types, except for the original value, which is automatically casted as a float.

To set the context of what we are working with, let's start with an original value.

Original Value

Common Options

-#, --progress-bar Make curl display a simple progress bar instead of the more informational standard meter.

-b, --cookie <name=data> Supply cookie with request. If no =, then specifies the cookie file to use (see -c).

-c, --cookie-jar <file name> File to save response cookies to.

	-- show running queries (pre 9.2)
	SELECT procpid, age(clock_timestamp(), query_start), usename, current_query
	FROM pg_stat_activity
	WHERE current_query != '<IDLE>' AND current_query NOT ILIKE '%pg_stat_activity%'
	ORDER BY query_start desc;

	-- show running queries (9.2)
	SELECT pid, age(clock_timestamp(), query_start), usename, query
	FROM pg_stat_activity
	WHERE query != '<IDLE>' AND query NOT ILIKE '%pg_stat_activity%'

	# List unique values in a DataFrame column
	# h/t @makmanalp for the updated syntax!
	df['Column Name'].unique()

	# Convert Series datatype to numeric (will error if column has non-numeric values)
	# h/t @makmanalp
	pd.to_numeric(df['Column Name'])

	# Convert Series datatype to numeric, changing non-numeric values to NaN
	# h/t @makmanalp for the updated syntax!

	var arr = {
	max: function(array) {
	return Math.max.apply(null, array);
	},

	min: function(array) {
	return Math.min.apply(null, array);
	},

	range: function(array) {

	# this forces dpkg not to call sync() after package extraction and speeds up install
	RUN echo "force-unsafe-io" > /etc/dpkg/dpkg.cfg.d/02apt-speedup
	# we don't need and apt cache in a container
	RUN echo "Acquire::http {No-Cache=True;};" > /etc/apt/apt.conf.d/no-cache

	<!doctype html>
	<title>Site Maintenance</title>
	<style>
	body { text-align: center; padding: 150px; }
	h1 { font-size: 50px; }
	body { font: 20px Helvetica, sans-serif; color: #333; }
	article { display: block; text-align: left; width: 650px; margin: 0 auto; }
	a { color: #dc8100; text-decoration: none; }
	a:hover { color: #333; text-decoration: none; }
	</style>

	import xml.etree.cElementTree as ET
	from shapely.geometry import mapping, Polygon
	import fiona
	import os

	input_filename = "villages.osm"
	output_filename = "villages.shp"

	# Parse the XML from the OSM file
	tree = ET.ElementTree(file=input_filename)