Module: ActiveRecord::ConnectionAdapters::QueryCache

Included in:
AbstractAdapter
Defined in:
activerecord/lib/active_record/connection_adapters/abstract/query_cache.rb

Instance Attribute Summary collapse

Class Method Summary collapse

Instance Method Summary collapse

Instance Attribute Details

#query_cacheObject (readonly)

Returns the value of attribute query_cache


21
22
23
# File 'activerecord/lib/active_record/connection_adapters/abstract/query_cache.rb', line 21

def query_cache
  @query_cache
end

#query_cache_enabledObject (readonly)

Returns the value of attribute query_cache_enabled


21
22
23
# File 'activerecord/lib/active_record/connection_adapters/abstract/query_cache.rb', line 21

def query_cache_enabled
  @query_cache_enabled
end

Class Method Details

.dirties_query_cache(base, *method_names) ⇒ Object


9
10
11
12
13
14
15
16
17
18
# 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 <<-end_code, __FILE__, __LINE__ + 1
      def #{method_name}(*)                         # def update_with_query_dirty(*)
        clear_query_cache if @query_cache_enabled   #   clear_query_cache if @query_cache_enabled
        super                                       #   super
      end                                           # end
    end_code
  end
end

.included(base) ⇒ Object

:nodoc:


5
6
7
# File 'activerecord/lib/active_record/connection_adapters/abstract/query_cache.rb', line 5

def included(base) #:nodoc:
  dirties_query_cache base, :insert, :update, :delete
end

Instance Method Details

#cacheObject

Enable the query cache within the block.


30
31
32
33
34
35
36
# 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
  clear_query_cache
  @query_cache_enabled = old
end

#clear_query_cacheObject

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.


60
61
62
# File 'activerecord/lib/active_record/connection_adapters/abstract/query_cache.rb', line 60

def clear_query_cache
  @query_cache.clear
end

#disable_query_cache!Object


42
43
44
# 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!Object


38
39
40
# File 'activerecord/lib/active_record/connection_adapters/abstract/query_cache.rb', line 38

def enable_query_cache!
  @query_cache_enabled = true
end

#initializeObject


23
24
25
26
27
# 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

#select_all(arel, name = nil, binds = []) ⇒ Object


64
65
66
67
68
69
70
71
# 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)
    sql = to_sql(arel, binds)
    cache_sql(sql, binds) { super(sql, name, binds) }
  else
    super
  end
end

#uncachedObject

Disable the query cache within the block.


47
48
49
50
51
52
# 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