It is not necessary to store QueryCache in a thread local since the cache is local to the connection object which is managed by the connection pool

1 files changed, 14 insertions, 27 deletions

diff --git a/activerecord/lib/active_record/connection_adapters/abstract/query_cache.rb b/activerecord/lib/active_record/connection_adapters/abstract/query_cache.rb
index 8543bbf872..950bd72101 100644
--- a/activerecord/lib/active_record/connection_adapters/abstract/query_cache.rb
+++ b/activerecord/lib/active_record/connection_adapters/abstract/query_cache.rb
@@ -15,7 +15,7 @@ module ActiveRecord
           method_names.each do |method_name|
             base.class_eval <<-end_code, __FILE__, __LINE__
               def #{method_name}_with_query_dirty(*args)
-                clear_query_cache if query_cache_enabled
+                clear_query_cache if @query_cache_enabled
                 #{method_name}_without_query_dirty(*args)
               end
 
@@ -25,37 +25,24 @@ module ActiveRecord
         end
       end
 
-      def query_cache_enabled
-        Thread.current['query_cache_enabled']
-      end
-
-      def query_cache_enabled=(flag)
-        Thread.current['query_cache_enabled'] = flag
-      end
-
-      def query_cache
-        Thread.current["query_cache_for_#{@config[:database]}"] ||= {}
-      end
-
-      def query_cache=(cache)
-        Thread.current["query_cache_for_#{@config[:database]}"] = cache
-      end
+      attr_reader :query_cache, :query_cache_enabled
 
       # Enable the query cache within the block.
       def cache
-        old, self.query_cache_enabled = query_cache_enabled, true
+        old, @query_cache_enabled = @query_cache_enabled, true
+        @query_cache ||= {}
         yield
       ensure
         clear_query_cache
-        self.query_cache_enabled = old
+        @query_cache_enabled = old
       end
 
       # Disable the query cache within the block.
       def uncached
-        old, self.query_cache_enabled = query_cache_enabled, false
+        old, @query_cache_enabled = @query_cache_enabled, false
         yield
       ensure
-        self.query_cache_enabled = old
+        @query_cache_enabled = old
       end
 
       # Clears the query cache.
@@ -65,11 +52,11 @@ module ActiveRecord
       # the same SQL query and repeatedly return the same result each time, silently
       # undermining the randomness you were expecting.
       def clear_query_cache
-        query_cache.clear if query_cache
+        @query_cache.clear if @query_cache
       end
 
       def select_all_with_query_cache(*args)
-        if query_cache_enabled
+        if @query_cache_enabled
           cache_sql(args.first) { select_all_without_query_cache(*args) }
         else
           select_all_without_query_cache(*args)
@@ -77,8 +64,8 @@ module ActiveRecord
       end
 
       def columns_with_query_cache(*args)
-        if query_cache_enabled
-          query_cache["SHOW FIELDS FROM #{args.first}"] ||= columns_without_query_cache(*args)
+        if @query_cache_enabled
+          @query_cache["SHOW FIELDS FROM #{args.first}"] ||= columns_without_query_cache(*args)
         else
           columns_without_query_cache(*args)
         end
@@ -87,11 +74,11 @@ module ActiveRecord
       private
         def cache_sql(sql)
           result =
-            if query_cache.has_key?(sql)
+            if @query_cache.has_key?(sql)
               log_info(sql, "CACHE", 0.0)
-              query_cache[sql]
+              @query_cache[sql]
             else
-              query_cache[sql] = yield
+              @query_cache[sql] = yield
             end
 
           if Array === result