[Rails5] Avoid un-needed collation dumps.

Author: metaskills

lib/active_record/connection_adapters/sqlserver/database_statements.rb

@@ -80,15 +80,15 @@ def release_savepoint(name = current_savepoint_name)
         end
 
         def case_sensitive_comparison(table, attribute, column, value)
-          if !value.nil? && column.collation && !column.case_sensitive?
+          if value && value.acts_like?(:string)
             table[attribute].eq(Arel::Nodes::Bin.new(Arel::Nodes::BindParam.new))
           else
             super
           end
         end
 
         def can_perform_case_insensitive_comparison_for?(column)
-          column.case_sensitive?
+          column.type == :string
         end
         private :can_perform_case_insensitive_comparison_for?
 

lib/active_record/connection_adapters/sqlserver/database_tasks.rb

@@ -24,10 +24,9 @@ def charset
         end
 
         def collation
-          select_value "SELECT DATABASEPROPERTYEX(DB_NAME(), 'Collation')"
+          @collation ||= select_value "SELECT DATABASEPROPERTYEX(DB_NAME(), 'Collation')"
         end
 
-
         private
 
         def create_database_options(options={})

lib/active_record/connection_adapters/sqlserver/schema_dumper.rb

@@ -0,0 +1,16 @@
+module ActiveRecord
+  module ConnectionAdapters
+    module SQLServer
+      module SchemaDumper
+
+        private
+
+        def schema_collation(column)
+          return unless column.collation
+          column.collation if column.collation != collation
+        end
+
+      end
+    end
+  end
+end

lib/active_record/connection_adapters/sqlserver/schema_statements.rb

@@ -301,10 +301,7 @@ def column_definitions(table_name)
             columns.NUMERIC_SCALE AS numeric_scale,
             columns.NUMERIC_PRECISION AS numeric_precision,
             columns.DATETIME_PRECISION AS datetime_precision,
-            CASE
-              WHEN columns.COLLATION_NAME <> DATABASEPROPERTYEX(DB_NAME(), 'Collation') THEN columns.COLLATION_NAME
-              ELSE NULL
-            END AS [collation],
+            columns.COLLATION_NAME AS [collation],
             columns.ordinal_position,
             CASE
               WHEN columns.DATA_TYPE IN ('nchar','nvarchar','char','varchar') THEN columns.CHARACTER_MAXIMUM_LENGTH

lib/active_record/connection_adapters/sqlserver_adapter.rb

@@ -14,6 +14,7 @@
 require 'active_record/connection_adapters/sqlserver/transaction'
 require 'active_record/connection_adapters/sqlserver/errors'
 require 'active_record/connection_adapters/sqlserver/schema_creation'
+require 'active_record/connection_adapters/sqlserver/schema_dumper'
 require 'active_record/connection_adapters/sqlserver/schema_statements'
 require 'active_record/connection_adapters/sqlserver/sql_type_metadata'
 require 'active_record/connection_adapters/sqlserver/showplan'
@@ -32,6 +33,7 @@ class SQLServerAdapter < AbstractAdapter
               SQLServer::Quoting,
               SQLServer::DatabaseStatements,
               SQLServer::Showplan,
+              SQLServer::SchemaDumper,
               SQLServer::SchemaStatements,
               SQLServer::DatabaseLimits,
               SQLServer::DatabaseTasks
@@ -169,14 +171,19 @@ def reconnect!
 
       def disconnect!
         super
-        @spid = nil
         case @connection_options[:mode]
         when :dblib
           @connection.close rescue nil
         end
         @connection = nil
       end
 
+      def clear_cache!
+        super
+        @spid = nil
+        @collation = nil
+      end
+
       def reset!
         reset_transaction
         do_execute 'IF @@TRANCOUNT > 0 ROLLBACK TRANSACTION'

lib/active_record/connection_adapters/sqlserver_column.rb

@@ -20,7 +20,7 @@ def is_utf8?
       end
 
       def case_sensitive?
-        collation && !collation.match(/_CI/)
+        collation && collation.match(/_CS/)
       end
 
     end

test/support/sql_counter_sqlserver.rb

@@ -17,7 +17,8 @@ def capture_sql_ss
       /SELECT @@version/,
       /SELECT @@TRANCOUNT/,
       /(BEGIN|COMMIT|ROLLBACK|SAVE) TRANSACTION/,
-      /SELECT CAST\(.* AS .*\) AS value/
+      /SELECT CAST\(.* AS .*\) AS value/,
+      /SELECT DATABASEPROPERTYEX/im
     ]
 
     sqlcounter = ObjectSpace.each_object(ActiveRecord::SQLCounter).to_a.first