postgres segfault

segfault.rb

require 'active_record'
require 'parallel'
ActiveRecord::Base.establish_connection(adapter: 'postgresql', pool: 25, username: 'postgres', host: 'localhost', database: 'postgres')
ActiveRecord::Base.connection.execute "DROP DATABASE IF EXISTS segfault"
ActiveRecord::Base.connection.execute "CREATE DATABASE segfault"
ActiveRecord::Base.establish_connection(adapter: 'postgresql', pool: 25, username: 'postgres', host: 'localhost', database: 'segfault')
ActiveRecord::Base.connection.execute <<-SQL
CREATE TABLE test_data(
  tracker_id  integer not null,
  created_at timestamp,
  processed boolean
);
SQL

(Date.new(2015,1,1) ..Date.new(2015,1,3)).each do |date|
  s= Time.now
pref = date.to_s.gsub('-','_')
ActiveRecord::Base.connection.execute <<-SQL
CREATE TABLE test_data_#{pref} (
  CHECK ( date("created_at") = '#{date}')
)
INHERITS (test_data)
SQL

ActiveRecord::Base.connection.execute <<-SQL
INSERT INTO test_data_#{pref} (tracker_id, created_at, processed)
SELECT i%10000, '#{date}'::date + (i % 86400) * INTERVAL '1 s', false
FROM generate_series(1, 1e6::integer) i
SQL
ActiveRecord::Base.connection.execute <<-SQL
CREATE INDEX tracker_id_and_created_at#{pref} ON test_data_#{pref} (tracker_id, created_at)
SQL
puts "done #{date} in #{Time.now - s}"
end

puts "test starting waiting to segfault...."
tracker_up = 200
updates = (1..1e6).select{|i| i%10_00 == tracker_up}.map{|i| Date.new(2015,1,2) + (i%86400).seconds}
Parallel.each_with_index(updates, in_threads: 6) do |time, idx|
  ActiveRecord::Base.connection_pool.with_connection do |con|
    if idx == 0
      con.execute <<-SQL
        CREATE TEMPORARY TABLE outtbl ON COMMIT DROP AS
          WITH affected AS (
            UPDATE test_data t SET processed = true
            WHERE tracker_id BETWEEN #{tracker_up - 100} AND #{tracker_up + 100}
            AND NOT processed
            RETURNING
              date(t.created_at) as date, tracker_id, created_at
          )
          SELECT * FROM affected
      SQL
    end
    con.execute <<-SQL
      UPDATE test_data SET tracker_id = 400
      WHERE tracker_id = #{tracker_up}
      and created_at = '#{time}'
      and date(created_at) = '#{time.to_date}'
    SQL
  end
end

run with

$ gem install activerecord
$ gem install pg
$ gem install parallel
$ ruby segfault.rb