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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

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const parseAddr = (addr) => {
    const sepList = ['省', '市', '市', '县', '区', '街道', '乡', '镇']
    const res = []

    let rest = addr
    for (let sep of sepList) {
        let m = rest.split(sep, 2)
        let current
        if (m.length > 1) {
            current = m[0] + sep

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fcuntion() {
  var text = encodeURIComponent(window.getSelection().toString() || window.document.title);
  var url = encodeURIComponent(window.location.href);
  var dstUrl = 'https://twitter.com/intent/tweet?url=' + url +   '&text=' + text;
  var windowName = 'Tweet Intent';
  var features = 'width=600,height=350,left=600,top=200';

  window.open(dstUrl, windowName, features);
};

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create schema shard_1;  
create sequence shard_1.global_id_sequence;

CREATE OR REPLACE FUNCTION shard_1.id_generator(OUT result bigint) AS $$  
DECLARE  
    our_epoch bigint := 1314220021721;
    seq_id bigint;
    now_millis bigint;
    -- the id of this DB shard, must be set for each
    -- schema shard you have - you could pass this as a parameter too

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Scaling your API with rate limiters

The following are examples of the four types rate limiters discussed in the accompanying blog post. In the examples below I've used pseudocode-like Ruby, so if you're unfamiliar with Ruby you should be able to easily translate this approach to other languages. Complete examples in Ruby are also provided later in this gist.

In most cases you'll want all these examples to be classes, but I've used simple functions here to keep the code samples brief.

Request rate limiter

This uses a basic token bucket algorithm and relies on the fact that Redis scripts execute atomically. No other operations can run between fetching the count and writing the new count.

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local ffi = require("ffi")

-- cut from https://github.com/facebook/rocksdb/blob/e59cb2a19b2971707d75552ae517586ca0785a6a/include/rocksdb/c.h
ffi.cdef[[
/* Exported types */

typedef struct rocksdb_t                 rocksdb_t;
typedef struct rocksdb_backup_engine_t   rocksdb_backup_engine_t;
typedef struct rocksdb_backup_engine_info_t   rocksdb_backup_engine_info_t;
typedef struct rocksdb_restore_options_t rocksdb_restore_options_t;

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from cffi import FFI

ffi = FFI()


# copied from https://github.com/google/leveldb/blob/master/include/leveldb/c.h
ffi.cdef("""
/* Exported types */

typedef struct leveldb_t               leveldb_t;

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Hello World In Python 10 Ways

1. general

print('Hello World')

2. sys stdout

import sys

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// demo_cpu.c

#include <stdbool.h>
#include <stdint.h>
#include <stdio.h>
#include <stdlib.h>

#define ISROM(a) ((a) < 16)
#define ISRAM(a) ((a) >= 16 && (a) < 20)

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Homebrew build logs for gcc on macOS 10.13.3
Build date: 2018-03-07 09:59:22