Add back cache for internal queries

Author: wpolicarpo

lib/active_record/connection_adapters/sqlserver/schema_statements.rb

@@ -415,15 +415,13 @@ def column_definitions(table_name)
             ci[:default_function] = begin
               default = ci[:default_value]
               if default.nil? && view_exists
-                default = uncached do
-                  select_value %{
-                    SELECT c.COLUMN_DEFAULT
-                    FROM #{database}.INFORMATION_SCHEMA.COLUMNS c
-                    WHERE
-                      c.TABLE_NAME = '#{view_tblnm}'
-                      AND c.COLUMN_NAME = '#{views_real_column_name(table_name, ci[:name])}'
-                  }.squish, 'SCHEMA'
-                end
+                default = select_value %{
+                  SELECT c.COLUMN_DEFAULT
+                  FROM #{database}.INFORMATION_SCHEMA.COLUMNS c
+                  WHERE
+                    c.TABLE_NAME = '#{view_tblnm}'
+                    AND c.COLUMN_NAME = '#{views_real_column_name(table_name, ci[:name])}'
+                }.squish, 'SCHEMA'
               end
               case default
               when nil
@@ -442,7 +440,7 @@ def column_definitions(table_name)
                        else ci[:type]
                        end
                 value = default.match(/\A\((.*)\)\Z/m)[1]
-                value = uncached { select_value("SELECT CAST(#{value} AS #{type}) AS value3", 'SCHEMA') }
+                value = select_value("SELECT CAST(#{value} AS #{type}) AS value", 'SCHEMA')
                 [value, nil]
               end
             end

test/cases/helper_sqlserver.rb

@@ -2,6 +2,7 @@
 require 'bundler/setup'
 Bundler.require :default, :development
 require 'pry'
+require 'support/core_ext/query_cache'
 require 'support/minitest_sqlserver'
 require 'support/test_in_memory_oltp'
 require 'cases/helper'

test/support/core_ext/query_cache.rb

@@ -0,0 +1,29 @@
+require 'active_record/connection_adapters/sqlserver_adapter'
+
+module SqlIgnoredCache
+  extend ActiveSupport::Concern
+
+  IGNORED_SQL = [
+    /INFORMATION_SCHEMA\.(TABLES|VIEWS|COLUMNS|KEY_COLUMN_USAGE)/im,
+    /SELECT @@version/,
+    /SELECT @@TRANCOUNT/,
+    /(BEGIN|COMMIT|ROLLBACK|SAVE) TRANSACTION/,
+    /SELECT CAST\(.* AS .*\) AS value/,
+    /SELECT DATABASEPROPERTYEX/im
+  ]
+
+  # We don't want to coerce every ActiveRecord test that relies on `query_cache`
+  # just because we do more queries than the other adapters.
+  #
+  # Removing internal queries from the cache will make AR tests pass without
+  # compromising cache outside tests.
+  def cache_sql(sql, name, binds)
+    result = super
+    @query_cache.delete_if { |k, v| k =~ Regexp.union(IGNORED_SQL) }
+    result
+  end
+end
+
+ActiveSupport.on_load(:active_record) do
+  ActiveRecord::ConnectionAdapters::SQLServerAdapter.prepend(SqlIgnoredCache)
+end