class ActiveSupport::Cache::MemoryStore

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 Phusion Passenger or puma clustered mode), 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.

Constants

PER_ENTRY_OVERHEAD

Public Class Methods

new(options = nil) click to toggle source

Calls superclass method ActiveSupport::Cache::Store.new

# File lib/active_support/cache/memory_store.rb, line 20
def initialize(options = nil)
  options ||= {}
  super(options)
  @data = {}
  @key_access = {}
  @max_size = options[:size] || 32.megabytes
  @max_prune_time = options[:max_prune_time] || 2
  @cache_size = 0
  @monitor = Monitor.new
  @pruning = false
end

Public Instance Methods

cleanup(options = nil) click to toggle source

Preemptively iterates through all stored keys and removes the ones which have expired.

# File lib/active_support/cache/memory_store.rb, line 42
def cleanup(options = nil)
  options = merged_options(options)
  instrument(:cleanup, size: @data.size) do
    keys = synchronize { @data.keys }
    keys.each do |key|
      entry = @data[key]
      delete_entry(key, options) if entry && entry.expired?
    end
  end
end

clear(options = nil) click to toggle source

Delete all data stored in a given cache store.

# File lib/active_support/cache/memory_store.rb, line 33
def clear(options = nil)
  synchronize do
    @data.clear
    @key_access.clear
    @cache_size = 0
  end
end

decrement(name, amount = 1, options = nil) click to toggle source

Decrement an integer value in the cache.

# File lib/active_support/cache/memory_store.rb, line 84
def decrement(name, amount = 1, options = nil)
  modify_value(name, -amount, options)
end

delete_matched(matcher, options = nil) click to toggle source

Deletes cache entries if the cache key matches a given pattern.

# File lib/active_support/cache/memory_store.rb, line 89
def delete_matched(matcher, options = nil)
  options = merged_options(options)
  instrument(:delete_matched, matcher.inspect) do
    matcher = key_matcher(matcher, options)
    keys = synchronize { @data.keys }
    keys.each do |key|
      delete_entry(key, options) if key.match(matcher)
    end
  end
end

increment(name, amount = 1, options = nil) click to toggle source

Increment an integer value in the cache.

# File lib/active_support/cache/memory_store.rb, line 79
def increment(name, amount = 1, options = nil)
  modify_value(name, amount, options)
end

prune(target_size, max_time = nil) click to toggle source

To ensure entries fit within the specified memory prune the cache by removing the least recently accessed entries.

# File lib/active_support/cache/memory_store.rb, line 55
def prune(target_size, max_time = nil)
  return if pruning?
  @pruning = true
  begin
    start_time = Time.now
    cleanup
    instrument(:prune, target_size, from: @cache_size) do
      keys = synchronize { @key_access.keys.sort { |a, b| @key_access[a].to_f <=> @key_access[b].to_f } }
      keys.each do |key|
        delete_entry(key, options)
        return if @cache_size <= target_size || (max_time && Time.now - start_time > max_time)
      end
    end
  ensure
    @pruning = false
  end
end

pruning?() click to toggle source

Returns true if the cache is currently being pruned.

# File lib/active_support/cache/memory_store.rb, line 74
def pruning?
  @pruning
end