module Sequel::Plugins::PgXminOptimisticLocking

  1. lib/sequel/plugins/pg_xmin_optimistic_locking.rb

By default, the plugin allows using the xmin= setter method to either increase or decrease the lock value. To prevent increases, which could potentially be used to skip an update when it update should be made, you can use the :prevent_increase plugin argument:

plugin :pg_xmin_optimistic_locking, prevent_increase: true

This plugin may not work with the class_table_inheritance plugin.

This plugin relies on the instance_filters plugin.

Methods

Public Class

  1. apply
  2. configure

Constants

WILDCARD = LiteralString.new('*').freeze  

Public Class methods

apply(model, prevent_increase: false)

Define the xmin column accessor

[show source] 
   # File lib/sequel/plugins/pg_xmin_optimistic_locking.rb
39 def self.apply(model, prevent_increase: false)
40   model.instance_exec do
41     plugin(:optimistic_locking_base)
42     @lock_column = :xmin
43     def_column_accessor(:xmin)
44   end
45 end
configure(model, prevent_increase: false)

Update the dataset to append the xmin column if it is usable and there is a dataset for the model.

[show source] 
   # File lib/sequel/plugins/pg_xmin_optimistic_locking.rb
49 def self.configure(model, prevent_increase: false)
50   model.instance_exec do
51     set_dataset(@dataset) if @dataset
52     # SEQUEL6: Make prevent_increase true by default
53     prevent_lock_column_increase! if prevent_increase
54   end
55 end