Module: ActiveRecord::ConnectionAdapters::QueryCache

### Home Classes Methods

### In Files

- lib/active_record/connection_adapters/abstract/query_cache.rb

### Methods

- ::dirties_query_cache
- ::included
- #cache
- #clear_query_cache
- #select_all
- #uncached

### Files

- README.rdoc

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# ActiveRecord::ConnectionAdapters::QueryCache

### Attributes

query_cache[R]
query_cache_enabled[R]

### Public Class Methods

dirties_query_cache(base, *method_names) click to toggle source

    # File lib/active_record/connection_adapters/abstract/query_cache.rb, line 11
    def dirties_query_cache(base, *method_names)
      method_names.each do |method_name|
        base.class_eval               def #{method_name}(*)                         # def update_with_query_dirty(*args)                clear_query_cache if @query_cache_enabled   #   clear_query_cache if @query_cache_enabled                super                                       #   update_without_query_dirty(*args)              end                                           # end, __FILE__, __LINE__ + 1
      end
    end

included(base) click to toggle source

    # File lib/active_record/connection_adapters/abstract/query_cache.rb, line 7
    def included(base)
      dirties_query_cache base, :insert, :update, :delete
    end

### Public Instance Methods

cache() click to toggle source

Enable the query cache within the block.

    # File lib/active_record/connection_adapters/abstract/query_cache.rb, line 26
    def cache
      old, @query_cache_enabled = @query_cache_enabled, true
      yield
    ensure
      clear_query_cache
      @query_cache_enabled = old
    end

clear_query_cache() click to toggle 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 lib/active_record/connection_adapters/abstract/query_cache.rb, line 48
    def clear_query_cache
      @query_cache.clear
    end

select_all(*args) click to toggle source

    # File lib/active_record/connection_adapters/abstract/query_cache.rb, line 52
    def select_all(*args)
      if @query_cache_enabled
        cache_sql(args.first) { super }
      else
        super
      end
    end

uncached() click to toggle source

Disable the query cache within the block.

    # File lib/active_record/connection_adapters/abstract/query_cache.rb, line 35
    def uncached
      old, @query_cache_enabled = @query_cache_enabled, false
      yield
    ensure
      @query_cache_enabled = old
    end

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