Vasiliy Zyablitsev zyablitsev

PostgreSQL DATE, TIMESTAMP, and INTERVAL cheat sheet

Working with DATE, TIMESTAMP, and INTERVAL in PostgreSQL can be confusing. In this article I will go over the three date/time related data types, and the two most useful date/time functions: DATE_PART and DATE_TRUNC. Finally, I will provide some real life examples of how these types and functions can be used within queries.

Types

PostgreSQL Date/Time Documentation

DATE

The DATE type contains the year, month, and day of a date. It is not possible to do any type of time related functions on a DATE without first converting it to a TIMESTAMP. Subtracting two DATE values from one another results in an INT representing the # of days between.

TIMESTAMP

The TIMESTAMP type contains a year, month, day, hour, minute, second, and microsecond. This is the type that I most often use.

How to run FreeBSD 13.0-BETA1 for ARM64 in QEMU on Apple Silicon Mac (MacBook Pro M1, etc)

This guide was adapted from https://gist.github.com/niw/e4313b9c14e968764a52375da41b4278#running-ubuntu-server-for-arm64

Running FreeBSD 13.0-BETA1 for ARM64

Install Xcode from App Store or install Command Line Tools on your Mac running on Apple Silicon.

Unfortunately, the Cisco AnyConnect client for Mac conflicts with Pow. And by "conflicts", I mean it causes a grey-screen-of-death kernel panic anytime you connect to the VPN and Pow is installed.

As an alternative, there is OpenConnect, a command-line client for Cisco's AnyConnect SSL VPN.

Here's how to get it set up on Mac OS X:

OpenConnect can be installed via homebrew:
```
 brew update
```

brew install openconnect

Securing traffic to upstream servers with client certificates

Info: https://www.nginx.com/resources/admin-guide/nginx-https-upstreams/

Creating and Signing Your Certs

Source: http://nategood.com/client-side-certificate-authentication-in-ngi

This is SSL, so you'll need an cert-key pair for you/the server, the api users/the client and a CA pair. You will be the CA in this case (usually a role played by VeriSign, thawte, GoDaddy, etc.), signing your client's certs. There are plenty of tutorials out there on creating and signing certificates, so I'll leave the details on this to someone else and just quickly show a sample here to give a complete tutorial. NOTE: This is just a quick sample of creating certs and not intended for production.

Never touch your local /etc/hosts file in OS X again

NOTE this has been done properly by a guy here: https://www.stevenrombauts.be/2018/01/use-dnsmasq-instead-of-etc-hosts/

You should go and do that now, ignore all of this.

To setup your computer to work with *.dev domains, e.g. project.dev, awesome.dev and so on, without having to add to your hosts file each time.

	# Stop service
	Get-Service CmService \| Stop-Service -Force

	# Disable the Sandbox feature
	Disable-WindowsOptionalFeature –FeatureName "Containers-DisposableClientVM" -Online

	# Clear the Zygotes and Sandboxes folders
	foreach($dir in @("Sandboxes","Zygotes")){
	Get-ChildItem "$env:ProgramData\Microsoft\Windows\Containers\$dir" \| ForEach-Object {
	Remove-Item -Path $_ -Recurse -Force -Verbose

	package main

	import (
	"bytes"
	"crypto/rand"
	"crypto/rsa"
	"crypto/tls"
	"crypto/x509"
	"crypto/x509/pkix"
	"encoding/pem"

	package main

	import (
	"crypto/rand"
	"crypto/rsa"
	"crypto/x509"
	"crypto/x509/pkix"
	"encoding/pem"
	"fmt"
	"math/big"

	# Make sure you grab the latest version
	curl -OL https://github.com/google/protobuf/releases/download/v3.5.1/protoc-3.5.1-linux-x86_64.zip

	# Unzip
	unzip protoc-3.5.1-linux-x86_64.zip -d protoc3

	# Move protoc to /usr/local/bin/
	sudo mv protoc3/bin/* /usr/local/bin/

	# Move protoc3/include to /usr/local/include/

	#install new versions of gcc and g++
	sudo apt-get install gcc-4.8 g++-4.8

	#remove existing alternatives
	sudo update-alternatives --remove-all gcc
	sudo update-alternatives --remove-all g++

	#add new and old version to update-alternatives db
	sudo update-alternatives --install /usr/bin/gcc gcc /usr/bin/gcc-4.6 60 --slave /usr/bin/g++ g++ /usr/bin/g++-4.6
	sudo update-alternatives --install /usr/bin/gcc gcc /usr/bin/gcc-4.8 40 --slave /usr/bin/g++ g++ /usr/bin/g++-4.8