Temporary Tablespaces created in Primary is missing in the Standby Database

You created a temporary tablespace in the Primary database, but it did not get created on Standby . [Release 9.2 to 12.2]

New tempfiles are not added automatically in the Physical Standby database because no redo is generated.

Tempfiles in the Standby are only used when your Standby is opened in read-only mode.

When you add tempfiles in the Primary database, new tempfiles are not added
automatically on the Physical Standby database because no redo is generated.

The tempfile auto-creation only kicks in when the Standby controlfile already contains the tempfile name.

You need to open the Physical Standby database in read-only mode.

This allows you to add a temporary file.

    SQL> alter database open read only.
    SQL> alter tablespace temp add tempfile '<name>' size ..