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.
Unlike other Cache
store implementations, MemoryStore
does not compress values by default. MemoryStore
does not benefit from compression as much as other Store
implementations, as it does not send data over a network. However, when compression is enabled, it still pays the full cost of compression in terms of cpu use.
MemoryStore
is thread-safe.
Constants
- DEFAULT_CODER
- PER_ENTRY_OVERHEAD
Public Class Methods
ActiveSupport::Cache::Store::new
# File lib/active_support/cache/memory_store.rb, line 44 def initialize(options = nil) options ||= {} # Disable compression by default. options[:compress] ||= false super(options) @data = {} @max_size = options[:size] || 32.megabytes @max_prune_time = options[:max_prune_time] || 2 @cache_size = 0 @monitor = Monitor.new @pruning = false end
Advertise cache versioning support.
# File lib/active_support/cache/memory_store.rb, line 58 def self.supports_cache_versioning? true end
Public Instance Methods
Preemptively iterates through all stored keys and removes the ones which have expired.
# File lib/active_support/cache/memory_store.rb, line 71 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 lib/active_support/cache/memory_store.rb, line 63 def clear(options = nil) synchronize do @data.clear @cache_size = 0 end end
Decrement an integer value in the cache.
# File lib/active_support/cache/memory_store.rb, line 113 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 lib/active_support/cache/memory_store.rb, line 118 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 lib/active_support/cache/memory_store.rb, line 108 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 lib/active_support/cache/memory_store.rb, line 84 def prune(target_size, max_time = nil) return if pruning? @pruning = true begin start_time = Concurrent.monotonic_time cleanup instrument(:prune, target_size, from: @cache_size) do keys = synchronize { @data.keys } keys.each do |key| delete_entry(key, **options) return if @cache_size <= target_size || (max_time && Concurrent.monotonic_time - start_time > max_time) end end ensure @pruning = false end end
Returns true if the cache is currently being pruned.
# File lib/active_support/cache/memory_store.rb, line 103 def pruning? @pruning end
Private Instance Methods
# File lib/active_support/cache/memory_store.rb, line 142 def cached_size(key, payload) key.to_s.bytesize + payload.bytesize + PER_ENTRY_OVERHEAD end
# File lib/active_support/cache/memory_store.rb, line 175 def delete_entry(key, **options) synchronize do payload = @data.delete(key) @cache_size -= cached_size(key, payload) if payload !!payload end end
# File lib/active_support/cache/memory_store.rb, line 183 def modify_value(name, amount, options) options = merged_options(options) synchronize do if num = read(name, options) num = num.to_i + amount write(name, num, options) num end end end
# File lib/active_support/cache/memory_store.rb, line 146 def read_entry(key, **options) entry = nil synchronize do payload = @data.delete(key) if payload @data[key] = payload entry = deserialize_entry(payload) end end entry end
# File lib/active_support/cache/memory_store.rb, line 158 def write_entry(key, entry, **options) payload = serialize_entry(entry) synchronize do return false if options[:unless_exist] && @data.key?(key) old_payload = @data[key] if old_payload @cache_size -= (old_payload.bytesize - payload.bytesize) else @cache_size += cached_size(key, payload) end @data[key] = payload prune(@max_size * 0.75, @max_prune_time) if @cache_size > @max_size true end end