DavidGoussev / iowait.txt

Created October 15, 2018 16:06 — forked from haridsv/iowait.txt

Mirroring https://blog.pregos.info/wp-content/uploads/2010/09/iowait.txt

	What exactly is "iowait"?

	To summarize it in one sentence, 'iowait' is the percentage
	of time the CPU is idle AND there is at least one I/O
	in progress.

	Each CPU can be in one of four states: user, sys, idle, iowait.
	Performance tools such as vmstat, iostat, sar, etc. print
	out these four states as a percentage. The sar tool can
	print out the states on a per CPU basis (-P flag) but most

DavidGoussev / psql-with-gzip-cheatsheet.sh

Created August 24, 2017 23:46 — forked from brock/psql-with-gzip-cheatsheet.sh

Exporting and Importing Postgres Databases using gzip

	# This is just a cheat sheet:

	# On production
	sudo -u postgres pg_dump database \| gzip -9 > database.sql.gz

	# On local
	scp -C production:~/database.sql.gz
	dropdb database && createdb database
	gunzip < database.sql.gz \| psql database

DavidGoussev / psql-with-gzip-cheatsheet.sh

Created August 24, 2017 23:46 — forked from brock/psql-with-gzip-cheatsheet.sh

Exporting and Importing Postgres Databases using gzip

	# This is just a cheat sheet:

	# On production
	sudo -u postgres pg_dump database \| gzip -9 > database.sql.gz

	# On local
	scp -C production:~/database.sql.gz
	dropdb database && createdb database
	gunzip < database.sql.gz \| psql database

DavidGoussev / pg_extract.sh

Created July 28, 2017 18:18 — forked from brock/pg_extract.sh

Extract all databases (or one by name) from a sql file created by pg_dumpall

	#!/bin/bash
	# extract all postgres databases from a sql file created by pg_dumpall
	# this script outputs one .sql file for each database in the original .sql file
	# unless you pass the name of a database in the dump

	if [ $# -lt 1 ]
	then
	echo "Usage: $0 <postgresql sql dump> [dbname]" >&2
	exit 1
	fi

DavidGoussev / pg_stat_statements

Last active July 6, 2017 21:44 — forked from troyk/pg_stat_statements

enable postgres pg_stat_statements

	1) see re: increasing shmmax http://stackoverflow.com/a/10629164/1283020

	2) add to postgresql.conf:
	shared_preload_libraries = 'pg_stat_statements' # (change requires restart)
	136 pg_stat_statements.max = 1000
	137 pg_stat_statements.track = all

	3) restart postgres

	4) check it out in psql

DavidGoussev / postgres_config.md

Created April 4, 2017 23:25 — forked from rgreenjr/postgres_config.md

PostgreSQL Configuration Optimization

Memory

Only four values really matter:

shared-buffers: below 2GB: set it to 20% of full memory; below 32GB: 25% of your full memory.

DavidGoussev / postgresql_upgrade.sh

Created April 4, 2017 23:24 — forked from rgreenjr/postgresql_upgrade.sh

PostgreSQL Upgrading

	# Taken from http://robots.thoughtbot.com/post/33706558963/migrating-data-from-an-upgraded-postgres
	#
	# Note: these steps assume installation with Homebrew.

	# Initialize a new database, adding a .new suffix to the directory that Homebrew recommends.

	initdb /usr/local/var/postgres.new -E utf8

	# Run the upgrade script, providing the correct paths for the various flags.

DavidGoussev / postgres_queries_and_commands.sql

Created April 4, 2017 23:23 — forked from rgreenjr/postgres_queries_and_commands.sql

Useful PostgreSQL Queries and Commands

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

DavidGoussev / nodejs_contributing.js

Created January 17, 2017 03:54

nodejs contributing

DavidGoussev / ransomNoteProblem.js

Created August 12, 2016 04:26 — forked from clarketm/ransomNoteProblem.js

Ransom Note Problem (JavaScript)

	function isRansomNotePossible(newsArticle, ransomNote) {
	var availableChars = {};

	for (var r = 0; r < newsArticle.length; r++) {
	var asciiCode = newsArticle.charCodeAt(r);
	availableChars[asciiCode] = (availableChars[asciiCode] \|\| 0) + 1
	}

	for (var r = 0; r < ransomNote.length; r++) {
	var asciiCode = ransomNote.charCodeAt(r);

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