class ActiveRecord::Batches::BatchEnumerator

Attributes

finish[R]

The primary key value at which the BatchEnumerator ends, inclusive of the value.

relation[R]

The relation from which the BatchEnumerator yields batches.

start[R]

The primary key value from which the BatchEnumerator starts, inclusive of the value.

Public Instance Methods

batch_size() click to toggle source

The size of the batches yielded by the BatchEnumerator.

# File lib/active_record/relation/batches/batch_enumerator.rb, line 28
def batch_size
  @of
end
delete_all() click to toggle source

Deletes records in batches. Returns the total number of rows affected.

Person.in_batches.delete_all

See Relation#delete_all for details of how each batch is deleted.

# File lib/active_record/relation/batches/batch_enumerator.rb, line 66
def delete_all
  sum(&:delete_all)
end
destroy_all() click to toggle source

Destroys records in batches. Returns the total number of rows affected.

Person.where("age < 10").in_batches.destroy_all

See Relation#destroy_all for details of how each batch is destroyed.

# File lib/active_record/relation/batches/batch_enumerator.rb, line 97
def destroy_all
  sum do |relation|
    relation.destroy_all.count(&:destroyed?)
  end
end
each(&block) click to toggle source

Yields an ActiveRecord::Relation object for each batch of records.

Person.in_batches.each do |relation|
  relation.update_all(awesome: true)
end
# File lib/active_record/relation/batches/batch_enumerator.rb, line 108
def each(&block)
  enum = @relation.to_enum(:in_batches, of: @of, start: @start, finish: @finish, load: false, cursor: @cursor, order: @order, use_ranges: @use_ranges)
  return enum.each(&block) if block_given?
  enum
end
each_record(&block) click to toggle source

Looping through a collection of records from the database (using the all method, for example) is very inefficient since it will try to instantiate all the objects at once.

In that case, batch processing methods allow you to work with the records in batches, thereby greatly reducing memory consumption.

Person.in_batches.each_record do |person|
  person.do_awesome_stuff
end

Person.where("age > 21").in_batches(of: 10).each_record do |person|
  person.party_all_night!
end

If you do not provide a block to each_record, it will return an Enumerator for chaining with other methods:

Person.in_batches.each_record.with_index do |person, index|
  person.award_trophy(index + 1)
end
# File lib/active_record/relation/batches/batch_enumerator.rb, line 53
def each_record(&block)
  return to_enum(:each_record) unless block_given?

  @relation.to_enum(:in_batches, of: @of, start: @start, finish: @finish, load: true, cursor: @cursor, order: @order).each do |relation|
    relation.records.each(&block)
  end
end
touch_all(...) click to toggle source

Touches records in batches. Returns the total number of rows affected.

Person.in_batches.touch_all

See Relation#touch_all for details of how each batch is touched.

# File lib/active_record/relation/batches/batch_enumerator.rb, line 86
def touch_all(...)
  sum do |relation|
    relation.touch_all(...)
  end
end
update_all(updates) click to toggle source

Updates records in batches. Returns the total number of rows affected.

Person.in_batches.update_all("age = age + 1")

See Relation#update_all for details of how each batch is updated.

# File lib/active_record/relation/batches/batch_enumerator.rb, line 75
def update_all(updates)
  sum do |relation|
    relation.update_all(updates)
  end
end