class AddQuotedPosts < ActiveRecord::Migration def change create_table :quoted_posts do |t| t.integer :post_id, null: false t.integer :quoted_post_id, null: false t.timestamps end add_index :quoted_posts, [:post_id, :quoted_post_id], unique: true add_index :quoted_posts, [:quoted_post_id, :post_id], unique: true # NOTE this can be done in pg but too much of a headache id = 0 while id = backfill_batch(id, 1000); end end def backfill_batch(start_id, batch_size) results = execute < #{start_id} ORDER BY id LIMIT #{batch_size} SQL max_id = nil results.each do |row| post_id, max_id = row["id"].to_i doc = Nokogiri::HTML.fragment(row["cooked"]) uniq = {} doc.css("aside.quote[data-topic]").each do |a| topic_id = a['data-topic'].to_i post_number = a['data-post'].to_i next if uniq[[topic_id, post_number]] uniq[[topic_id, post_number]] = true execute "INSERT INTO quoted_posts(post_id, quoted_post_id, created_at, updated_at) SELECT #{post_id}, id, created_at, updated_at FROM posts WHERE post_number = #{post_number} AND topic_id = #{topic_id}" end end max_id end end