Module: Switchman::ActiveRecord::StatementCache

Defined in:
lib/switchman/active_record/statement_cache.rb

Defined Under Namespace

Modules: BindMap, ClassMethods

Instance Method Summary collapse

Instance Method Details

#execute(*args, &block) ⇒ Object

since the StatememtCache is only implemented for basic relations in AR::Base#find, AR::Base#find_by and AR::Association#get_records, we can make some assumptions about the shard source (e.g. infer from the primary key or use the current shard)



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# File 'lib/switchman/active_record/statement_cache.rb', line 28

def execute(*args, &block)
  params, connection = args
  klass = @klass
  target_shard = nil
  if (primary_index = bind_map.primary_value_index)
    primary_value = params[primary_index]
    target_shard = Shard.local_id_for(primary_value)[1]
  end
  current_shard = Shard.current(klass.connection_class_for_self)
  target_shard ||= current_shard

  bind_values = bind_map.bind(params, current_shard, target_shard)

  target_shard.activate(klass.connection_class_for_self) do
    sql = qualified_query_builder(target_shard, klass).sql_for(bind_values, connection)
    klass.find_by_sql(sql, bind_values, &block)
  end
end

#initialize(arel, bind_map, klass = nil) ⇒ Object 



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# File 'lib/switchman/active_record/statement_cache.rb', line 16

def initialize(arel, bind_map, klass = nil)
  @arel = arel
  @bind_map = bind_map
  @klass = klass
  @qualified_query_builders = {}
end

#qualified_query_builder(shard, klass) ⇒ Object 



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# File 'lib/switchman/active_record/statement_cache.rb', line 47

def qualified_query_builder(shard, klass)
  @qualified_query_builders[shard.id] ||= klass.connection.cacheable_query(self.class, @arel).first
end