sequel_example.rb

require 'sequel'
require 'pg'

db_config = {
  adapter:          'postgres',
  host:             'localhost',
  database:         'asdf',
  max_connections:  10,
}

DB = Sequel.postgres(db_config)

# Migration
DB.create_table! :postgres_sequel_models do
  primary_key :id
  String :name, null: false, unique: true
  Integer :idx
end

# Model
class PostgresSequelModel < Sequel::Model
end
PSM = PostgresSequelModel

10.times.map do
  Thread.new do
    DB.transaction(rollback: :always) do
      PSM.new(name: 'name').save
      sleep 1
    end
  end
end.each(&:join)