Certain SQL commands and settings were found to be major performance problems with CTools' Oracle. These were:
- validating the db connection with a simple SQL statement
- setting the default transaction isolation level
(Note: doing a rollback after each connection use, and setting the auto-commit each time to the default value were also a problem and have been fixed already in the TRUNK)
Changes were put in CTools to address this, but the kernel db configuration was not structured to allow these changes to be applied to the TRUNK, so that the OOTB Sakai supports HSQLDB with these settings, and for Oracle, we can disable them as needed in the sakai.properties files.
Change the kernel db configuration to allow this, and recommend the Oracle settings (here, and in the various distributed properties files and examples).