Chaitanya Sharma phoenix24

A few show tricks to find slow queries in mongodb

Enable profiling

First, you have to enable profiling

> db.setProfilingLevel(1)

Now let it run for a while. It collects the slow queries ( > 100ms) into a capped collections, so queries go in and if it's full, old queries go out, so don't be surprised that it's a moving target...

ANNOUNCEMENT

I have moved this over to the Tech Interview Cheat Sheet Repo and has been expanded and even has code challenges you can run and practice against!

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tldr: go build only produces an executable for main packages. Check the package name of your main file is main.

I am an idiot. Its only through mistakes that you learn tho. I have recently been running into issues with my new golang projects. ONLY the new ones. Whenever I try to make a new project, it would always have issues. The biggest issue is the fact that "go build" would not produce an executable without "-o main.exe" as arguments. When an executable was produced, if I ran it I got

$ ./main.exe
./main.exe: line 1: syntax error near unexpected token \`newline\'
./main.exe: line 1: \`!<arch>\'

	(function() {
	// Notes from http://news.ycombinator.com/item?id=1952531
	var notes = {
	"suspended cymbal":"zk",
	"snare":"bschk",
	"brush":"pv",
	"bass":"bk",
	"flam1":"tk",
	"roll tap":"vk",
	"flam2":"kt",

	ctrl-z
	bg

	touch /tmp/stdout
	touch /tmp/stderr
	gdb -p $!

	# In GDB
	p dup2(open("/tmp/stdout", 1), 1)
	p dup2(open("/tmp/stderr", 1), 2)

	package typedactorrefs

	import akka.actor._
	import akka.pattern.AskSupport
	import akka.util.Timeout
	import scala.concurrent.Future
	import typedactorrefs.Server.ServerMessage
	import scala.concurrent.duration._
	import typedactorrefs.Server.GetModule
	import typedactorrefs.Server.Module

	#!/usr/bin/env python
	"""
	Use byzanz to create a GIF screencast of a specific window.

	Required tools:
	sudo apt-get install byzanz x11-utils xdotool

	A tip: use an extra-long duration (-d 100), record your shot, and use
	gimp to shorten the duration of the last frame. You need to rename the layer
	from "Frame 123 (100000 ms) (combine)" to "Frame 123 (1000 ms) (combine)".

	// Include gulp
	var gulp = require('gulp');

	// Include Our Plugins
	var sass = require('gulp-sass');
	var concat = require('gulp-concat');
	var uglify = require('gulp-uglify');
	var rename = require('gulp-rename');
	var autoprefixer = require('gulp-autoprefixer');
	var minifycss = require('gulp-minify-css');

	-Xmx10g
	m2.xlarge (4 virtual cores)

	Both Jetty and Netty execute the same code--generate 8k of random bits and compute a sha1, returning it over the wire.

	INTERNAL (Benchmark tool runs on same machine)
	--------

	Jetty:

	/**
	* Settings
	*/

	var settings = {
	scripts: true, // Turn on/off script tasks
	polyfills: true, // Turn on/off polyfill tasks
	styles: false, // Turn on/off style tasks
	svgs: false, // Turn on/off SVG tasks
	static: false, // Turn on/off static file copying