Merge pull request #22444 from kamipo/connection_options_is_only_needed_for_mysql_adapter

`connection_options` is only needed for `MysqlAdapter`

activerecord/lib/active_record/connection_adapters/abstract_mysql_adapter.rb

@@ -144,7 +144,7 @@ def attributes_for_hash
       # FIXME: Make the first parameter more similar for the two adapters
       def initialize(connection, logger, connection_options, config)
         super(connection, logger)
-        @connection_options, @config = connection_options, config
+        @config = config
         @quoted_column_names, @quoted_table_names = {}, {}
 
         @visitor = Arel::Visitors::MySQL.new self

activerecord/lib/active_record/connection_adapters/mysql2_adapter.rb

@@ -16,8 +16,7 @@ def mysql2_connection(config)
       end
 
       client = Mysql2::Client.new(config)
-      options = [config[:host], config[:username], config[:password], config[:database], config[:port], config[:socket], 0]
-      ConnectionAdapters::Mysql2Adapter.new(client, logger, options, config)
+      ConnectionAdapters::Mysql2Adapter.new(client, logger, nil, config)
     rescue Mysql2::Error => error
       if error.message.include?("Unknown database")
         raise ActiveRecord::NoDatabaseError

activerecord/lib/active_record/connection_adapters/mysql_adapter.rb

@@ -82,6 +82,7 @@ def initialize(connection, logger, connection_options, config)
         super
         @statements = StatementPool.new(self.class.type_cast_config_to_integer(config.fetch(:statement_limit) { 1000 }))
         @client_encoding = nil
+        @connection_options = connection_options
         connect
       end