kenn

Local Domains for Development

tl;dr

Install dnsmasq to make all .test domains point to localhost on your Mac.

Why and how to set up .test domain on your Mac

When we work on a local machine for development, we usually point to localhost:3000 in the browser. But using that domain for everything comes with some downsides when you work on multiple projects.

kenn

import { useRevalidator } from '@remix-run/react'
import { useEffect } from 'react'

// Rendering will ensure all page loaders are revalidated according to a given
// frequency
export const Poller = ({ seconds }) => {
  usePolling(seconds)

  return null
}

kenn

def scroll_merge(klass, source_names, target_name, batch_size = 100):
    Qdrant.recreate(target_name) # reset target collection

    def generator(source_name):
        offset = None

        while True:
            # Scroll https://qdrant.tech/documentation/points/#scroll-points
            # https://github.com/qdrant/qdrant-client/blob/master/qdrant_client/qdrant_client.py#L412
            result = Qdrant.client.scroll(

kenn

#!/usr/bin/env ruby

#------------------------------------------------------------------------------
# Aggregate Print useful information from /proc/[pid]/smaps
#
# pss  - Roughly the amount of memory that is "really" being used by the pid
# swap - Amount of swap this process is currently using
#
# Reference:
#  http://www.mjmwired.net/kernel/Documentation/filesystems/proc.txt#361

kenn

CPU Price Performance: DigitalOcean vs Linode

On DigitalOcean, as you go up the plan, you get higher per-core price as well.

https://www.digitalocean.com/pricing

$5 1 core     - $5/core
$10 1 core - $10/core

kenn

SELECT * FROM
  (SELECT id FROM sort_keys ORDER BY sort_key) INNER JOIN main_table ON sort_keys.id = main_table.id
WHERE ... OFFSET 0 LIMIT 10

kenn

require 'digest'

a = (0..100000).map{|i| Digest::SHA1.hexdigest(i.to_s).hex }
a.map.with_index{|i,idx| i > a[idx-1] }.group_by{|i| i }.map{|k,v| [k,v.size] }

# => [[true, 499235], [false, 500766]]

kenn

# Undo require 'active_support/core_ext/object/to_json'
require 'yajl'
[Object, Array, Hash].each do |klass|
  klass.class_eval <<-RUBY, __FILE__, __LINE__
    def jsonize(options = nil)
      ::Yajl::Encoder.encode(self)
    end
  RUBY
end

kenn

E, [2013-04-22T15:04:52.652797 #8734] ERROR -- : listen loop error: closed stream (IOError)
E, [2013-04-22T15:04:52.652852 #8734] ERROR -- : /usr/local/rvm/gems/ruby-2.0.0-p0/gems/unicorn-4.6.2/lib/unicorn/http_server.rb:652:in `select'
E, [2013-04-22T15:04:52.652886 #8734] ERROR -- : /usr/local/rvm/gems/ruby-2.0.0-p0/gems/unicorn-4.6.2/lib/unicorn/http_server.rb:652:in `worker_loop'
E, [2013-04-22T15:04:52.652918 #8734] ERROR -- : /usr/local/rvm/gems/ruby-2.0.0-p0/gems/newrelic_rpm-3.6.0.83/lib/new_relic/agent/instrumentation/unicorn_instrumentation.rb:22:in `call'
E, [2013-04-22T15:04:52.652950 #8734] ERROR -- : /usr/local/rvm/gems/ruby-2.0.0-p0/gems/newrelic_rpm-3.6.0.83/lib/new_relic/agent/instrumentation/unicorn_instrumentation.rb:22:in `block (4 levels) in <top (required)>'
E, [2013-04-22T15:04:52.652981 #8734] ERROR -- : /usr/local/rvm/gems/ruby-2.0.0-p0/gems/unicorn-4.6.2/lib/unicorn/http_server.rb:500:in `spawn_missing_workers'
E, [2013-04-22T15:04:52.653013 #8734] ERROR -- : /usr/local/rvm/gems/ruby

kenn

# hdparm -tf /dev/xvda

/dev/xvda:
 Timing buffered disk reads: 714 MB in  3.01 seconds = 237.55 MB/sec

# bonnie++ -b -u root

Version  1.96       ------Sequential Output------ --Sequential Input- --Random-
Concurrency   1     -Per Chr- --Block-- -Rewrite- -Per Chr- --Block-- --Seeks--
Machine        Size K/sec %CP K/sec %CP K/sec %CP K/sec %CP K/sec %CP  /sec %CP