From 51d9b9a821a8f3f11fc5f52321df6ee05e4e1327 Mon Sep 17 00:00:00 2001 From: Simeon Simeonov Date: Sat, 20 Jul 2013 23:08:06 -0400 Subject: [Fixes #11512] improves cache size calculation in ActiveSupport::Cache::MemoryStore Previously, the cache size of `ActiveSupport::Cache::MemoryStore` was calculated as the sum of the size of its entries, ignoring the size of keys and any data structure overhead. This could lead to the calculated cache size sometimes being 10-100x smaller than the memory used, e.g., in the case of small values. The size of a key/entry pair is now calculated via `#cached_size`: def cached_size(key, entry) key.to_s.bytesize + entry.size + PER_ENTRY_OVERHEAD end The value of `PER_ENTRY_OVERHEAD` is 240 bytes based on an [empirical estimation](https://gist.github.com/ssimeonov/6047200) for 64-bit MRI on 1.9.3 and 2.0. Fixes GH#11512 https://github.com/rails/rails/issues/11512 --- activesupport/test/caching_test.rb | 28 ++++++++++++++++++++++++++-- 1 file changed, 26 insertions(+), 2 deletions(-) (limited to 'activesupport/test') diff --git a/activesupport/test/caching_test.rb b/activesupport/test/caching_test.rb index d2382f0f5b..df570d485a 100644 --- a/activesupport/test/caching_test.rb +++ b/activesupport/test/caching_test.rb @@ -713,8 +713,8 @@ end class MemoryStoreTest < ActiveSupport::TestCase def setup - @record_size = ActiveSupport::Cache::Entry.new("aaaaaaaaaa").size - @cache = ActiveSupport::Cache.lookup_store(:memory_store, :expires_in => 60, :size => @record_size * 10) + @record_size = ActiveSupport::Cache.lookup_store(:memory_store).send(:cached_size, 1, ActiveSupport::Cache::Entry.new("aaaaaaaaaa")) + @cache = ActiveSupport::Cache.lookup_store(:memory_store, :expires_in => 60, :size => @record_size * 10 + 1) end include CacheStoreBehavior @@ -764,6 +764,30 @@ class MemoryStoreTest < ActiveSupport::TestCase assert !@cache.exist?(1), "no entry" end + def test_prune_size_on_write_based_on_key_length + @cache.write(1, "aaaaaaaaaa") && sleep(0.001) + @cache.write(2, "bbbbbbbbbb") && sleep(0.001) + @cache.write(3, "cccccccccc") && sleep(0.001) + @cache.write(4, "dddddddddd") && sleep(0.001) + @cache.write(5, "eeeeeeeeee") && sleep(0.001) + @cache.write(6, "ffffffffff") && sleep(0.001) + @cache.write(7, "gggggggggg") && sleep(0.001) + @cache.write(8, "hhhhhhhhhh") && sleep(0.001) + @cache.write(9, "iiiiiiiiii") && sleep(0.001) + long_key = '*' * 2 * @record_size + @cache.write(long_key, "llllllllll") + assert @cache.exist?(long_key) + assert @cache.exist?(9) + assert @cache.exist?(8) + assert @cache.exist?(7) + assert @cache.exist?(6) + assert !@cache.exist?(5), "no entry" + assert !@cache.exist?(4), "no entry" + assert !@cache.exist?(3), "no entry" + assert !@cache.exist?(2), "no entry" + assert !@cache.exist?(1), "no entry" + end + def test_pruning_is_capped_at_a_max_time def @cache.delete_entry (*args) sleep(0.01) -- cgit v1.2.3