vasanthk

System Design Cheatsheet

Picking the right architecture = Picking the right battles + Managing trade-offs

Basic Steps

1. Clarify and agree on the scope of the system

• User cases (description of sequences of events that, taken together, lead to a system doing something useful)
  • Who is going to use it?
  • How are they going to use it?

dypsilon

Backend Development

• node.js
  • Installation paths: use one of these techniques to install node and npm without having to sudo.
  • Node.js HOWTO: Install Node+NPM as user (not root) under Unix OSes
  • Felix's Node.js Guide
  • Creating a REST API using Node.js, Express, and MongoDB
  • Node Cellar Sample Application with Backbone.js, Twitter Bootstrap, Node.js, Express, and MongoDB
  • JavaScript Event Loop
• Node.js for PHP programmers

dypsilon

Frontend Development

Attention: the list was moved to

https://github.com/dypsilon/frontend-dev-bookmarks

This page is not maintained anymore, please update your bookmarks.

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rgreenjr

-- 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%' 

jboner

Latency Comparison Numbers (~2012)
----------------------------------
L1 cache reference                           0.5 ns
Branch mispredict                            5   ns
L2 cache reference                           7   ns                      14x L1 cache
Mutex lock/unlock                           25   ns
Main memory reference                      100   ns                      20x L2 cache, 200x L1 cache
Compress 1K bytes with Zippy             3,000   ns        3 us
Send 1K bytes over 1 Gbps network       10,000   ns       10 us
Read 4K randomly from SSD*             150,000   ns      150 us          ~1GB/sec SSD

mxcl

<?xml version="1.0" encoding="UTF-8"?>
<scheme name="Colbalt" version="1" parent_scheme="Default">
  <option name="LINE_SPACING" value="1.1" />
  <option name="EDITOR_FONT_SIZE" value="12" />
  <option name="EDITOR_FONT_NAME" value="Monaco" />
  <colors>
    <option name="CARET_COLOR" value="ffffff" />
    <option name="CARET_ROW_COLOR" value="133d61" />
    <option name="FOLDING_TREE_COLOR" value="466a8a" />
    <option name="INDENT_GUIDE" value="123b5f" />