YanhaoYang

  def template_digest    
    tmpl = lookup_context.find(action_name, _prefixes)
    ActionView::Digestor.digest(name: tmpl.virtual_path, finder: lookup_context)
  end

YanhaoYang

    server {
      listen       80;
      server_name  [domain name];
 
      root   [Rails root]/public;

      location @passenger {
        passenger_enabled on;
        passenger_app_env production;
      }

YanhaoYang

#!/usr/bin/env bash

if [ -n "$1" ];
then

  ssh_config=$(mktemp -t ssh_config)
  vagrant ssh-config > "$ssh_config"
  scp -F "$ssh_config" $@

else

YanhaoYang

module Sidekiq
  module Middleware
    module Server
      class TaggedLogger

        def call(worker, item, queue)
          tag = "#{worker.class.to_s} #{SecureRandom.hex(12)}"
          ::Rails.logger.tagged(tag) do
            job_info = "Start at #{Time.now.to_default_s}: #{item.inspect}"
            ::Rails.logger.info(job_info)

YanhaoYang

module Concerns
  module Transactions
    extend ActiveSupport::Concern

    def transaction_begin
      ActiveRecord::Base.connection.begin_db_transaction
      ActiveRecord::Base.connection.increment_open_transactions
      render nothing: true
    end

YanhaoYang

# main logic
def hi
  'hi'
end

# rspec tests
require 'rspec'
describe "hi" do

  it "says 'hi'" do

YanhaoYang

*/2  *  *  *  *  if [[ `pmset -g batt | awk -F'[^0-9]*' '{ print $3 }'` -lt 20 ]];then say "Battery low";fi

YanhaoYang

• Show active connections

  • SELECT * FROM pg_stat_activity;
  • ps aux | grep postgres | wc -l (roughly, when you cannot connect to it)

• Show @max_connections@

  • In psql: SHOW max_connections; (SHOW ALL;)

• SQL: SELECT * FROM pg_settings WHERE name = 'max_connections';

YanhaoYang

# 16 GB shared memory
$ sysctl -w kernel.shmmax=17179869184
# A page is almost always 4096 bytes except in unusual kernel configurations with "huge pages" (use getconf PAGE_SIZE to verify).
$ sysctl -w kernel.shmall=4194304

To preserve the settings between reboots, in /etc/sysctl.conf:
kernel.shmmax=17179869184
kernel.shmall=4194304

YanhaoYang

Date.parse

1.8.7: parse(str='-4712-01-01', comp=false, sg=ITALY)
1.9.3: parse(string='-4712-01-01T00:00:00+00:00'[, comp=true[, start=ITALY]])

Note: the default values of comp are different.

Enumerator#next