class ActiveSupport::Cache::MemoryStore
A
cache store implementation which stores everything into memory in the same process. If you're running multiple Ruby on Quails
server processes (which is the case if you're using Phusion Passenger or puma clustered mode), then this means that Quails
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
ActiveSupport::Cache::Store::new
# File activesupport/lib/active_support/cache/memory_store.rb, line 21 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
Preemptively iterates through all stored keys and removes the ones which have expired.
# File activesupport/lib/active_support/cache/memory_store.rb, line 43 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
Delete all data stored in a given cache store.
# File activesupport/lib/active_support/cache/memory_store.rb, line 34 def clear(options = nil) synchronize do @data.clear @key_access.clear @cache_size = 0 end end
Decrement an integer value in the cache.
# File activesupport/lib/active_support/cache/memory_store.rb, line 85 def decrement(name, amount = 1, options = nil) modify_value(name, -amount, options) end
Deletes cache entries if the cache key matches a given pattern.
# File activesupport/lib/active_support/cache/memory_store.rb, line 90 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 an integer value in the cache.
# File activesupport/lib/active_support/cache/memory_store.rb, line 80 def increment(name, amount = 1, options = nil) modify_value(name, amount, options) 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 56 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
Returns true if the cache is currently being pruned.
# File activesupport/lib/active_support/cache/memory_store.rb, line 75 def pruning? @pruning end
Private Instance Methods
# File activesupport/lib/active_support/cache/memory_store.rb, line 115 def cached_size(key, entry) key.to_s.bytesize + entry.size + PER_ENTRY_OVERHEAD end
# File activesupport/lib/active_support/cache/memory_store.rb, line 148 def delete_entry(key, options) synchronize do @key_access.delete(key) entry = @data.delete(key) @cache_size -= cached_size(key, entry) if entry !!entry end end
# File activesupport/lib/active_support/cache/memory_store.rb, line 157 def modify_value(name, amount, options) synchronize do options = merged_options(options) if num = read(name, options) num = num.to_i + amount write(name, num, options) num end end end
# File activesupport/lib/active_support/cache/memory_store.rb, line 119 def read_entry(key, options) entry = @data[key] synchronize do if entry @key_access[key] = Time.now.to_f else @key_access.delete(key) end end entry end
# File activesupport/lib/active_support/cache/memory_store.rb, line 131 def write_entry(key, entry, options) entry.dup_value! synchronize do old_entry = @data[key] return false if @data.key?(key) && options[:unless_exist] if old_entry @cache_size -= (old_entry.size - entry.size) else @cache_size += cached_size(key, entry) end @key_access[key] = Time.now.to_f @data[key] = entry prune(@max_size * 0.75, @max_prune_time) if @cache_size > @max_size true end end