Module: ActiveRecord::OnDemand::DeleteAllByPk::ClassMethods

Defined in:
lib/ar-ondemand/delete_all_by_pk.rb

Instance Method Summary collapse

Instance Method Details

#delete_all_by_pk(options = {}) ⇒ Object

Use this instead of delete_all to perform a delete using the PK of the table, which prevents a complete table scan that locks it Based on find_in_batches function



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# File 'lib/ar-ondemand/delete_all_by_pk.rb', line 11

def delete_all_by_pk(options = {})
  relation = self

  # TODO Clean this up after dropping support for Rails 3
  if ActiveRecord::VERSION::MAJOR == 3
    relation = self.scoped unless respond_to? :arel
  else
    relation = self.all unless respond_to? :arel
  end

  unless relation.arel.orders.blank? && relation.arel.taken.blank?
    ::ActiveRecord::Base.logger.warn("Scoped order and limit are ignored, it's forced to be batch order and batch size")
  end

  start = options.delete(:start)
  batch_size = options.delete(:batch_size)

  relation = relation.reorder(batch_order_delete_all_by_pk).limit(batch_size) if batch_size
  records = query_delete_all_by_pk(start ? relation.where(relation.table[primary_key].gteq(start)) : relation)
  deleted = 0

  while records.any?
    records_size = records.size
    primary_key_offset = records.last

    deleted += self.unscoped.where(id: records).delete_all

    break if batch_size.nil? || records_size < batch_size

    records = query_delete_all_by_pk relation.where(relation.table[primary_key].gt(primary_key_offset))
  end

  deleted
end