Rajan Ponnappan vrajanap

PSQL

Magic words:

psql -U postgres

Some interesting flags (to see all, use -h or --help depending on your psql version):

-E: will describe the underlaying queries of the \ commands (cool for learning!)
-l: psql will list all databases and then exit (useful if the user you connect with doesn't has a default database, like at AWS RDS)

Turning PostgreSQL into a queue serving 10,000 jobs per second

RDBMS-based job queues have been criticized recently for being unable to handle heavy loads. And they deserve it, to some extent, because the queries used to safely lock a job have been pretty hairy. SELECT FOR UPDATE followed by an UPDATE works fine at first, but then you add more workers, and each is trying to SELECT FOR UPDATE the same row (and maybe throwing NOWAIT in there, then catching the errors and retrying), and things slow down.

On top of that, they have to actually update the row to mark it as locked, so the rest of your workers are sitting there waiting while one of them propagates its lock to disk (and the disks of however many servers you're replicating to). QueueClassic got some mileage out of the novel idea of randomly picking a row near the front of the queue to lock, but I can't still seem to get more than an an extra few hundred jobs per second out of it under heavy load.

So, many developers have started going straight t

This is not intended to be comprehensive or authoritative, just free online resources I've found valuable while learning more about Erlang.

Joe Armstrong's Swedish Institute of Computer Science homepage (Wayback Machine)

https://web.archive.org/web/20070429181654/http://www.sics.se/~joe/

Similar lists

Each of these commands will run an ad hoc http static server in your current (or specified) directory, available at http://localhost:8000. Use this power wisely.

Discussion on reddit.

Python 2.x

$ python -m SimpleHTTPServer 8000

	###
	###
	### UPDATE: For Win 11, I recommend using this tool in place of this script:
	### https://christitus.com/windows-tool/
	### https://github.com/ChrisTitusTech/winutil
	### https://www.youtube.com/watch?v=6UQZ5oQg8XA
	### iwr -useb https://christitus.com/win \| iex
	###
	### OR take a look at
	### https://github.com/HotCakeX/Harden-Windows-Security

	# See list of docker virtual machines on the local box
	$ docker-machine ls
	NAME ACTIVE URL STATE URL SWARM DOCKER ERRORS
	default * virtualbox Running tcp://192.168.99.100:2376 v1.9.1

	# Note the host URL 192.168.99.100 - it will be used later!

	# Build an image from current folder under given image name
	$ docker build -t gleb/demo-app .

	package main

	import "fmt"

	var enums []string

	type Enum int

	func (e Enum) String() string {
	return enums[int(e)]

	rm -f out
	mkfifo out
	trap "rm -f out" EXIT
	while true
	do
	cat out \| nc -w1 -l 1500 > >( # parse the netcat output, to build the answer redirected to the pipe "out".
	export REQUEST=
	while read line
	do
	line=$(echo "$line" \| tr -d '[\r\n]')

	# set prefix to control-f
	set -g prefix C-f

	#unbind system defined prefix
	unbind C-b

	# helps in faster key repetition
	set -sg escape-time 0

	# start session number from 1 rather than 0

	-- 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%'