chitchcock

Stevey's Google Platforms Rant

I was at Amazon for about six and a half years, and now I've been at Google for that long. One thing that struck me immediately about the two companies -- an impression that has been reinforced almost daily -- is that Amazon does everything wrong, and Google does everything right. Sure, it's a sweeping generalization, but a surprisingly accurate one. It's pretty crazy. There are probably a hundred or even two hundred different ways you can compare the two companies, and Google is superior in all but three of them, if I recall correctly. I actually did a spreadsheet at one point but Legal wouldn't let me show it to anyone, even though recruiting loved it.

I mean, just to give you a very brief taste: Amazon's recruiting process is fundamentally flawed by having teams hire for themselves, so their hiring bar is incredibly inconsistent across teams, despite various efforts they've made to level it out. And their operations are a mess; they don't real

jhowarth

class SessionsController < Devise::SessionsController
  
  def create
    resource = warden.authenticate!(:scope => resource_name, :recall => :failure)
    return sign_in_and_redirect(resource_name, resource)
  end
  
  def sign_in_and_redirect(resource_or_scope, resource=nil)
    scope = Devise::Mapping.find_scope!(resource_or_scope)
    resource ||= resource_or_scope

scottlowe

class Article < ActiveRecord::Base
  validates :title, :body, :presence => true

  # Note that ActiveRecord ARel from() doesn't appear to accommodate "?"
  # param placeholder, hence the need for manual parameter sanitization
  def self.tsearch_query(search_terms, limit = query_limit)
    words = sanitize(search_terms.scan(/\w+/) * "|")

    Article.from("articles, to_tsquery('pg_catalog.english', #{words}) as q").
      where("tsv @@ q").order("ts_rank_cd(tsv, q) DESC").limit(limit)

hgmnz

Types of index scans

Indexes

Sequential Scan:

• Read every row in the table
• No reading of index. Reading from indexes is also expensive.

peter

-- Order by one indexed column (FAST)
newsdesk_production=# explain analyze select * from pressreleases order by published_at DESC limit 100;
                                                                                   QUERY PLAN                                                                                    
---------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
 Limit  (cost=0.00..249.91 rows=100 width=1207) (actual time=26.070..716.453 rows=100 loops=1)
   ->  Index Scan Backward using pressreleases_published_at_index on pressreleases  (cost=0.00..964766.62 rows=386042 width=1207) (actual time=26.067..716.343 rows=100 loops=1)
 Total runtime: 716.709 ms
(3 rows)

- Order by two separately indexed columns (SLOW)