A cache store implementation which stores everything into memory in the same process. If you’re running multiple Ruby on Rails server processes (which is the case if you’re using mongrel_cluster or Phusion Passenger), then this means that Rails server process instances won’t be able to share cache data with each other and this may not be the most appropriate cache in that scenario.
This cache has a bounded size specified by the :size options to the initializer (default is 32Mb). When the cache exceeds the allotted size, a cleanup will occur which tries to prune the cache down to three quarters of the maximum size by removing the least recently used entries.
MemoryStore is thread-safe.
# File activesupport/lib/active_support/cache/memory_store.rb, line 19 19: def initialize(options = nil) 20: options ||= {} 21: super(options) 22: @data = {} 23: @key_access = {} 24: @max_size = options[:size] || 32.megabytes 25: @max_prune_time = options[:max_prune_time] || 2 26: @cache_size = 0 27: @monitor = Monitor.new 28: @pruning = false 29: end
# File activesupport/lib/active_support/cache/memory_store.rb, line 39 39: def cleanup(options = nil) 40: options = merged_options(options) 41: instrument(:cleanup, :size => @data.size) do 42: keys = synchronize{ @data.keys } 43: keys.each do |key| 44: entry = @data[key] 45: delete_entry(key, options) if entry && entry.expired? 46: end 47: end 48: end
Decrement an integer value in the cache.
# File activesupport/lib/active_support/cache/memory_store.rb, line 90 90: def decrement(name, amount = 1, options = nil) 91: synchronize do 92: options = merged_options(options) 93: if num = read(name, options) 94: num = num.to_i - amount 95: write(name, num, options) 96: num 97: else 98: nil 99: end 100: end 101: end
# File activesupport/lib/active_support/cache/memory_store.rb, line 103 103: def delete_matched(matcher, options = nil) 104: options = merged_options(options) 105: instrument(:delete_matched, matcher.inspect) do 106: matcher = key_matcher(matcher, options) 107: keys = synchronize { @data.keys } 108: keys.each do |key| 109: delete_entry(key, options) if key.match(matcher) 110: end 111: end 112: end
Increment an integer value in the cache.
# File activesupport/lib/active_support/cache/memory_store.rb, line 76 76: def increment(name, amount = 1, options = nil) 77: synchronize do 78: options = merged_options(options) 79: if num = read(name, options) 80: num = num.to_i + amount 81: write(name, num, options) 82: num 83: else 84: nil 85: end 86: end 87: end
To ensure entries fit within the specified memory prune the cache by removing the least recently accessed entries.
# File activesupport/lib/active_support/cache/memory_store.rb, line 52 52: def prune(target_size, max_time = nil) 53: return if pruning? 54: @pruning = true 55: begin 56: start_time = Time.now 57: cleanup 58: instrument(:prune, target_size, :from => @cache_size) do 59: keys = synchronize{ @key_access.keys.sort{|a,b| @key_access[a].to_f <=> @key_access[b].to_f} } 60: keys.each do |key| 61: delete_entry(key, options) 62: return if @cache_size <= target_size || (max_time && Time.now - start_time > max_time) 63: end 64: end 65: ensure 66: @pruning = false 67: end 68: end