Class: SafePgMigrations::Helpers::BatchOver

Inherits:
Object
  • Object
show all
Defined in:
lib/safe-pg-migrations/helpers/batch_over.rb

Overview

This helper class allows to iterate over records in batches, in a similar way to ActiveRecord’s ‘in_batches` method with the :use_ranges option, which was introduced in ActiveRecord 7.1, see:

- https://api.rubyonrails.org/classes/ActiveRecord/Batches.html#method-i-in_batches
- https://github.com/rails/rails/blob/v7.1.0/activerecord/CHANGELOG.md
- https://github.com/rails/rails/pull/45414
- https://github.com/rails/rails/commit/620f24782977b8e53e06cf0e2c905a591936e990

In ActiveRecord 8.1, ‘in_baches(use_ranges: true)` was optimized further to use less cpu, memory, and bandwidth, see:

- https://github.com/rails/rails/releases/tag/v8.1.0
- https://github.com/rails/rails/pull/51243
- https://github.com/rails/rails/commit/c097bf6c24443323da8fe64030dd963951121dea

If using ActiveRecord 8.1 or later, it’s recommended to use the built-in method, e.g.

User.in_batches(of: 100, use_ranges: true).each { |batch| ... }

Otherwise, this helper can be used as a fallback:

SafePgMigrations::Helpers::BatchOver.new(User, of: 100).each_batch { |batch| ... }

Instance Method Summary collapse

Constructor Details

#initialize(model, of: SafePgMigrations.config.backfill_batch_size) ⇒ BatchOver

Returns a new instance of BatchOver.



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# File 'lib/safe-pg-migrations/helpers/batch_over.rb', line 31

def initialize(model, of: SafePgMigrations.config.backfill_batch_size)
  @model = model
  @of = of

  @current_range = nil
end

Instance Method Details

#each_batch ⇒ Object 



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# File 'lib/safe-pg-migrations/helpers/batch_over.rb', line 38

def each_batch
  yield scope.where(primary_key => @current_range) while next_batch
end