🇻🇳 vinhjaxt

Optimizing postgresql table for more than 100K inserts per second

Create UNLOGGED table. This reduces the amount of data written to persistent storage by up to 2x.
Set WITH (autovacuum_enabled=false) on the table. This saves CPU time and IO bandwidth on useless vacuuming of the table (since we never DELETE or UPDATE the table).
Insert rows with COPY FROM STDIN. This is the fastest possible approach to insert rows into table.
Minimize the number of indexes in the table, since they slow down inserts. Usually an index on time timestamp with time zone is enough.
Add synchronous_commit = off to postgresql.conf.
Use table inheritance for fast removal of old data:

I was tired of Chrome eating all my laptop resources so I decided to put some limit to it with cgroup.

As I was using Ubuntu 12.04 with support for cgroup, I installed the package cgroup-bin and add the following group to the file /etc/cgconfig.conf:

group browsers {
    cpu {
#       Set the relative share of CPU resources equal to 25%
        cpu.shares = "256";
 }

Moved to git-repository: https://github.com/denji/awesome-http-benchmark

Tools

Located in alphabetical order (not prefer)

ab – slow and single threaded, written in C
apib – most of the features of ApacheBench (ab), also designed as a more modern replacement, written in C
autocannon – fast HTTP/1.1 benchmarking tool written in Node.js
baloo – Expressive end-to-end HTTP API testing made easy, written in Go (golang)

Better local require() paths for Node.js

Problem

When the directory structure of your Node.js application (not library!) has some depth, you end up with a lot of annoying relative paths in your require calls like:

const Article = require('../../../../app/models/article');

Those suck for maintenance and they're ugly.

	# Redis Cheatsheet
	# All the commands you need to know


	redis-server /path/redis.conf # start redis with the related configuration file
	redis-cli # opens a redis prompt


	# Strings.

	## IPv6 Tests
	http://[::ffff:169.254.169.254]
	http://[0:0:0:0:0:ffff:169.254.169.254]

	## AWS
	# Amazon Web Services (No Header Required)
	# from http://docs.aws.amazon.com/AWSEC2/latest/UserGuide/ec2-instance-metadata.html#instancedata-data-categories
	http://169.254.169.254/latest/meta-data/iam/security-credentials/dummy
	http://169.254.169.254/latest/user-data
	http://169.254.169.254/latest/user-data/iam/security-credentials/[ROLE NAME]

	#include "ets_sys.h"
	#include "driver/uart.h"
	#include "osapi.h"
	#include "mqtt.h"
	#include "wifi.h"
	#include "config.h"
	#include "debug.h"
	#include "gpio.h"
	#include "user_interface.h"

	#!/bin/sh
	DIR="tmp_"$$
	JAR=`echo $1 \| tr '.' ' ' \| awk '{ print $1 }'`
	rm -rf $JAR.jar
	mkdir $DIR
	cp $1 $DIR
	cd $DIR
	echo "** Compiling java file..."
	javac -d . -g $1
	echo "** Creating temporary jar..."

	// Converts an ArrayBuffer directly to base64, without any intermediate 'convert to string then
	// use window.btoa' step. According to my tests, this appears to be a faster approach:
	// http://jsperf.com/encoding-xhr-image-data/5

	/*
	MIT LICENSE

	Copyright 2011 Jon Leighton

	Permission is hereby granted, free of charge, to any person obtaining a copy of this software and associated documentation files (the "Software"), to deal in the Software without restriction, including without limitation the rights to use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of the Software, and to permit persons to whom the Software is furnished to do so, subject to the following conditions: