thorvn

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

int main() {
  int n = 3;
  int m = 3;
  int a[3][3] = { 0 };

  a[1][1] = 5;
  int x = 5;

thorvn

  def measure(no_gc = true, &block)
    if no_gc
      GC.disable
    else
      GC.start
    end
    memory_before = `ps -o rss= -p #{Process.pid}`.to_i/1024
    gc_stat_before = GC.stat
    time = Benchmark.realtime do
      yield

thorvn

#!/bin/sh 

# store start date to a variable
imeron=`date`

echo "Import started: OK"
dumpfile="/home/bob/bobiras.sql"

ddl="set names utf8; "
ddl="$ddl set global net_buffer_length=1000000;"

thorvn

Install apache + passenger

https://www.phusionpassenger.com/library/install/apache/install/oss/xenial/

thorvn

sizes = [10, 50, 100, 1000]

sizes.each do |size|
  array = size.times.map { |i| rand(size) }
  threshold = size / 2

  Benchmark.bmbm(2) do |x|
    x.report("select #{size}") do
      array.select { |item| item > threshold }
        .each { |item| item * item }

thorvn

Change password

ALTER USER 'root'@'localhost' IDENTIFIED WITH mysql_native_password BY '';

thorvn

filename = 'flowdata_201803052230.sql'

INSERT_MATCHER = 'INSERT INTO'
file = 1
counter = 1

File.open(filename, 'r').each do |line|
  next unless line.include? INSERT_MATCHER

  File.open(file.to_s + '.sql', 'a+') { |file| file.write("\n" + line) }

thorvn

Emacs dependencies

sudo apt-get install build-essential texinfo libx11-dev libxpm-dev libjpeg-dev libpng-dev libgif-dev libtiff-dev libgtk2.0-dev libncurses-dev libxpm-dev automake autoconf

Build emacs

mkdir emacs
cd emacs

thorvn

class A
  protected
  def protected_a
    puts "Protected A"
  end

  private
  def private_a
    puts "Private A"
  end

thorvn

1. Hạn chế việc sử dụng if else lồng nhau. Ở đầu function nên return các case sai sau đó mới viết logic cho function

2. Khi viết SQL không được nối chuỗi mà phải sử dụng param truyền vào câu truy vấn.

3. Sử dụng Active record hoặc Arel over raw queries

Example:

    # unless ids.blank?
    #   sql = "DELETE FROM links WHERE links.user_id = #{user_id.to_s} AND links.id IN (#{ids.to_s})"
    #   connection.execute(sql)
    # end
 return if ids.blank?