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author | Nahum Wild <nahum.wild@gmail.com> | 2009-01-15 21:28:10 -0600 |
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committer | Joshua Peek <josh@joshpeek.com> | 2009-01-15 21:29:32 -0600 |
commit | a53ad5bba37199047ba20194933e122bf6b0252f (patch) | |
tree | 65766ed28fb8518f706b39a688c974a1fed6519b /activesupport/lib/active_support/cache | |
parent | 7a0e7c7270548138a333bc39aab5aec80580174b (diff) | |
download | rails-a53ad5bba37199047ba20194933e122bf6b0252f.tar.gz rails-a53ad5bba37199047ba20194933e122bf6b0252f.tar.bz2 rails-a53ad5bba37199047ba20194933e122bf6b0252f.zip |
Added in a local per request cache to MemCacheStore. It acts as a buffer to stop unneccessary requests being sent through to memcache [#1653 state:resolved]
Signed-off-by: Joshua Peek <josh@joshpeek.com>
Diffstat (limited to 'activesupport/lib/active_support/cache')
-rw-r--r-- | activesupport/lib/active_support/cache/mem_cache_store.rb | 65 |
1 files changed, 61 insertions, 4 deletions
diff --git a/activesupport/lib/active_support/cache/mem_cache_store.rb b/activesupport/lib/active_support/cache/mem_cache_store.rb index f9a7fb1440..eed9faac6d 100644 --- a/activesupport/lib/active_support/cache/mem_cache_store.rb +++ b/activesupport/lib/active_support/cache/mem_cache_store.rb @@ -13,6 +13,7 @@ module ActiveSupport # server goes down, then MemCacheStore will ignore it until it goes back # online. # - Time-based expiry support. See #write and the +:expires_in+ option. + # - Per-request in memory cache for all communication with the MemCache server(s). class MemCacheStore < Store module Response # :nodoc: STORED = "STORED\r\n" @@ -22,6 +23,24 @@ module ActiveSupport DELETED = "DELETED\r\n" end + # this allows caching of the fact that there is nothing in the remote cache + NULL = 'mem_cache_store:null' + + THREAD_LOCAL_KEY = :mem_cache_store_cache + + class LocalCache + def initialize(app) + @app = app + end + + def call(env) + Thread.current[THREAD_LOCAL_KEY] = MemoryStore.new + @app.call(env) + ensure + Thread.current[THREAD_LOCAL_KEY] = nil + end + end + attr_reader :addresses # Creates a new MemCacheStore object, with the given memcached server @@ -42,7 +61,18 @@ module ActiveSupport def read(key, options = nil) # :nodoc: super - @data.get(key, raw?(options)) + + value = local_cache && local_cache.read(key) + if value == NULL + nil + elsif value.nil? + value = @data.get(key, raw?(options)) + local_cache.write(key, value || NULL) if local_cache + value + else + # forcing the value to be immutable + value.dup + end rescue MemCache::MemCacheError => e logger.error("MemCacheError (#{e}): #{e.message}") nil @@ -61,6 +91,7 @@ module ActiveSupport # memcache-client will break the connection if you send it an integer # in raw mode, so we convert it to a string to be sure it continues working. value = value.to_s if raw?(options) + local_cache.write(key, value || NULL) if local_cache response = @data.send(method, key, value, expires_in(options), raw?(options)) response == Response::STORED rescue MemCache::MemCacheError => e @@ -70,6 +101,7 @@ module ActiveSupport def delete(key, options = nil) # :nodoc: super + local_cache.write(key, NULL) if local_cache response = @data.delete(key, expires_in(options)) response == Response::DELETED rescue MemCache::MemCacheError => e @@ -80,14 +112,27 @@ module ActiveSupport def exist?(key, options = nil) # :nodoc: # Doesn't call super, cause exist? in memcache is in fact a read # But who cares? Reading is very fast anyway - !read(key, options).nil? + # Local cache is checked first, if it doesn't know then memcache itself is read from + value = local_cache.read(key) if local_cache + if value == NULL + false + elsif value + true + else + !read(key, options).nil? + end end def increment(key, amount = 1) # :nodoc: log("incrementing", key, amount) response = @data.incr(key, amount) - response == Response::NOT_FOUND ? nil : response + unless response == Response::NOT_FOUND + local_cache.write(key, response.to_s) if local_cache + response + else + nil + end rescue MemCache::MemCacheError nil end @@ -96,17 +141,25 @@ module ActiveSupport log("decrement", key, amount) response = @data.decr(key, amount) - response == Response::NOT_FOUND ? nil : response + unless response == Response::NOT_FOUND + local_cache.write(key, response.to_s) if local_cache + response + else + nil + end rescue MemCache::MemCacheError nil end def delete_matched(matcher, options = nil) # :nodoc: + # don't do any local caching at present, just pass + # through and let the error happen super raise "Not supported by Memcache" end def clear + local_cache.clear if local_cache @data.flush_all end @@ -115,6 +168,10 @@ module ActiveSupport end private + def local_cache + Thread.current[THREAD_LOCAL_KEY] + end + def expires_in(options) (options && options[:expires_in]) || 0 end |