W3cubDocs

module ActiveRecord::ConnectionAdapters::QueryCache

Attributes

query_cache[R]

query_cache_enabled[R]

Public Class Methods

dirties_query_cache(base, *method_names) Show source

# File activerecord/lib/active_record/connection_adapters/abstract/query_cache.rb, line 9
        def dirties_query_cache(base, *method_names)
          method_names.each do |method_name|
            base.class_eval "              def #{method_name}(*)
                clear_query_cache if @query_cache_enabled
                super
              end
", __FILE__, __LINE__ + 1
          end
        end

new(*) Show source

Calls superclass method

# File activerecord/lib/active_record/connection_adapters/abstract/query_cache.rb, line 23
def initialize(*)
  super
  @query_cache         = Hash.new { |h,sql| h[sql] = {} }
  @query_cache_enabled = false
end

Public Instance Methods

cache() { || ... } Show source

Enable the query cache within the block.

# File activerecord/lib/active_record/connection_adapters/abstract/query_cache.rb, line 30
def cache
  old, @query_cache_enabled = @query_cache_enabled, true
  yield
ensure
  @query_cache_enabled = old
  clear_query_cache unless @query_cache_enabled
end

clear_query_cache() Show source

Clears the query cache.

One reason you may wish to call this method explicitly is between queries that ask the database to randomize results. Otherwise the cache would see the same SQL query and repeatedly return the same result each time, silently undermining the randomness you were expecting.

# File activerecord/lib/active_record/connection_adapters/abstract/query_cache.rb, line 60
def clear_query_cache
  @query_cache.clear
end

disable_query_cache!() Show source

# File activerecord/lib/active_record/connection_adapters/abstract/query_cache.rb, line 42
def disable_query_cache!
  @query_cache_enabled = false
end

enable_query_cache!() Show source

# File activerecord/lib/active_record/connection_adapters/abstract/query_cache.rb, line 38
def enable_query_cache!
  @query_cache_enabled = true
end

select_all(arel, name = nil, binds = []) Show source

Calls superclass method

# File activerecord/lib/active_record/connection_adapters/abstract/query_cache.rb, line 64
def select_all(arel, name = nil, binds = [])
  if @query_cache_enabled && !locked?(arel)
    arel, binds = binds_from_relation arel, binds
    sql = to_sql(arel, binds)
    cache_sql(sql, binds) { super(sql, name, binds) }
  else
    super
  end
end

uncached() { || ... } Show source

Disable the query cache within the block.

# File activerecord/lib/active_record/connection_adapters/abstract/query_cache.rb, line 47
def uncached
  old, @query_cache_enabled = @query_cache_enabled, false
  yield
ensure
  @query_cache_enabled = old
end