diff options
Diffstat (limited to 'activerecord/lib/active_record')
| -rw-r--r-- | activerecord/lib/active_record/integration.rb | 8 | ||||
| -rw-r--r-- | activerecord/lib/active_record/relation.rb | 51 |
2 files changed, 44 insertions, 15 deletions
diff --git a/activerecord/lib/active_record/integration.rb b/activerecord/lib/active_record/integration.rb index b769541e95..c745bc1330 100644 --- a/activerecord/lib/active_record/integration.rb +++ b/activerecord/lib/active_record/integration.rb @@ -22,6 +22,14 @@ module ActiveRecord # # This is +true+, by default on Rails 5.2 and above. class_attribute :cache_versioning, instance_writer: false, default: false + + ## + # :singleton-method: + # Indicates whether to use a stable #cache_key method that is accompanied + # by a changing version in the #cache_version method on collections. + # + # This is +false+, by default until Rails 6.1. + class_attribute :collection_cache_versioning, instance_writer: false, default: false end # Returns a +String+, which Action Pack uses for constructing a URL to this diff --git a/activerecord/lib/active_record/relation.rb b/activerecord/lib/active_record/relation.rb index cd62b0b881..8eb71e6454 100644 --- a/activerecord/lib/active_record/relation.rb +++ b/activerecord/lib/active_record/relation.rb @@ -291,27 +291,23 @@ module ActiveRecord limit_value ? records.many? : size > 1 end - # Returns a cache key that can be used to identify the records fetched by - # this query. The cache key is built with a fingerprint of the sql query, - # the number of records matched by the query and a timestamp of the last - # updated record. When a new record comes to match the query, or any of - # the existing records is updated or deleted, the cache key changes. + # Returns a stable cache key that can be used to identify this query. + # The cache key is built with a fingerprint of the SQL query. # - # Product.where("name like ?", "%Cosmic Encounter%").cache_key - # # => "products/query-1850ab3d302391b85b8693e941286659-1-20150714212553907087000" + # Product.where("name like ?", "%Cosmic Encounter%").cache_key + # # => "products/query-1850ab3d302391b85b8693e941286659" # - # If the collection is loaded, the method will iterate through the records - # to generate the timestamp, otherwise it will trigger one SQL query like: + # If ActiveRecord::Base.collection_cache_versioning is turned off, as it was + # in Rails 6.0 and earlier, the cache key will also include a version. # - # SELECT COUNT(*), MAX("products"."updated_at") FROM "products" WHERE (name like '%Cosmic Encounter%') + # ActiveRecord::Base.collection_cache_versioning = false + # Product.where("name like ?", "%Cosmic Encounter%").cache_key + # # => "products/query-1850ab3d302391b85b8693e941286659-1-20150714212553907087000" # # You can also pass a custom timestamp column to fetch the timestamp of the # last updated record. # # Product.where("name like ?", "%Game%").cache_key(:last_reviewed_at) - # - # You can customize the strategy to generate the key on a per model basis - # overriding ActiveRecord::Base#collection_cache_key. def cache_key(timestamp_column = :updated_at) @cache_keys ||= {} @cache_keys[timestamp_column] ||= @klass.collection_cache_key(self, timestamp_column) @@ -321,6 +317,31 @@ module ActiveRecord query_signature = ActiveSupport::Digest.hexdigest(to_sql) key = "#{klass.model_name.cache_key}/query-#{query_signature}" + if cache_version(timestamp_column) + key + else + "#{key}-#{compute_cache_version(timestamp_column)}" + end + end + + # Returns a cache version that can be used together with the cache key to form + # a recyclable caching scheme. The cache version is built with the number of records + # matching the query, and the timestamp of the last updated record. When a new record + # comes to match the query, or any of the existing records is updated or deleted, + # the cache version changes. + # + # If the collection is loaded, the method will iterate through the records + # to generate the timestamp, otherwise it will trigger one SQL query like: + # + # SELECT COUNT(*), MAX("products"."updated_at") FROM "products" WHERE (name like '%Cosmic Encounter%') + def cache_version(timestamp_column = :updated_at) + if collection_cache_versioning + @cache_versions ||= {} + @cache_versions[timestamp_column] ||= compute_cache_version(timestamp_column) + end + end + + def compute_cache_version(timestamp_column) # :nodoc: if loaded? || distinct_value size = records.size if size > 0 @@ -356,9 +377,9 @@ module ActiveRecord end if timestamp - "#{key}-#{size}-#{timestamp.utc.to_s(cache_timestamp_format)}" + "#{size}-#{timestamp.utc.to_s(cache_timestamp_format)}" else - "#{key}-#{size}" + "#{size}" end end |