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Useful PostgreSQL Queries & Commands

All sizes in MB, change /1024/1024 to /1024/1024/1024 for GB.

Databases sizes

Without system databases

select
datname as database,
(pg_database_size(datname)/1024/1024) as size

Initialize a new site

with npx @docusaurus/init@latest init website classic

Configure your site

i18n: {
    defaultLocale: 'en',
    locales: ['en', 'it'],
    localeConfigs: {
      en: {

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London

Setup RAIDZ on Ubuntu Server 20.04 LTS

In this walkthrough we'll be using 4 brand new Seagate IronWolf Pro 10TB 7200rpm 256MB hard drives to setup a ZFS storage pool (RAIDZ 10).

1. ZFS

If you don't have ZFS already installed go ahead and run

sudo apt install zfsutils-linux

2. Disk Identifier & Sector sizes

Before we do anything with the drives we need the disk identifier and sector size for each drive for step 3.

	#!/usr/bin/env bash

	CIPHERS='ALL:eNULL'
	DELAY=${2:-0.1}
	SERVER=${1:?usage: $0 <host:port> [delay, default is ${DELAY}s] [ciphers, default is ${CIPHERS}]}
	MAXLEN=$(openssl ciphers "$CIPHERS" \| sed -e 's/:/\n/g' \| awk '{ if ( length > L ) { L=length} }END{ print L}')

	echo Using $(openssl version).

	declare -A TLSMAP=( [tls1_1]=cipher [tls1_2]=cipher [tls1_3]=ciphersuites )

	@Inherited
	@InterceptorBinding
	@Retention(RetentionPolicy.RUNTIME)
	@Target({ElementType.METHOD,ElementType.TYPE})
	public @interface Lock {
	LockType value() default LockType.WRITE;
	}

	-- 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%'

	#!/bin/bash
	# from https://chromium.woolyss.com/
	# and https://gist.github.com/addyosmani/5336747
	# and https://chromium.googlesource.com/chromium/src/+/lkgr/headless/README.md
	sudo apt-get update
	sudo apt-get install software-properties-common
	sudo add-apt-repository ppa:canonical-chromium-builds/stage
	sudo apt-get update
	sudo apt-get install chromium-browser
	chromium-browser --headless --no-sandbox http://example.org/

	import React, { ComponentProps } from 'react'
	import { ScrollView } from 'react-native'
	import { useDraggableScroll } from './use-draggable-scroll'

	export const DraggableScrollView = React.forwardRef<
	ScrollView,
	ComponentProps<typeof ScrollView>
	>(function DraggableScrollView(props, ref) {
	const { refs } = useDraggableScroll<ScrollView>({
	outerRef: ref,

	CREATE DATABASE company_db;
	USE company_db;
	-- CREATE TABLES
	CREATE TABLE employee(
	emp_id INT PRIMARY KEY,
	first_name VARCHAR(20),
	last_name VARCHAR(20),
	birth_date DATE,
	sex VARCHAR(1),
	salary INT,