Default exception handler: DDL sql execution error Debug: ORA-01408: such column list already indexed

CREATE UNIQUE INDEX m_badgback_useext2_uix ON m_badge_backpack (CASE WHEN externalbackpackid IS NOT NULL THEN userid ELSE NULL END, CASE WHEN externalbackpackid IS NOT NULL THEN externalbackpackid ELSE NULL END)

Error code: ddlexecuteerror

* line 492 of /lib/dml/moodle_database.php: ddl_change_structure_exception thrown

* line 277 of /lib/dml/oci_native_moodle_database.php: call to moodle_database->query_end()

* line 896 of /lib/dml/oci_native_moodle_database.php: call to oci_native_moodle_database->query_end()

* line 77 of /lib/ddl/database_manager.php: call to oci_native_moodle_database->change_database_structure()

* line 758 of /lib/ddl/database_manager.php: call to database_manager->execute_sql_arr()

* line 2263 of /lib/db/upgrade.php: call to database_manager->add_key()

* line 1875 of /lib/upgradelib.php: call to xmldb_main_upgrade()

* line 196 of /admin/cli/upgrade.php: call to upgrade_core()

!!! DDL sql execution error !!!

!! ORA-01408: such column list already indexed

CREATE UNIQUE INDEX m_badgback_useext2_uix ON m_badge_backpack (CASE WHEN externalbackpackid IS NOT NULL THEN userid ELSE NULL END, CASE WHEN externalbackpackid IS NOT NULL THEN externalbackpackid ELSE NULL END)

Error code: ddlexecuteerror !!

!! Stack trace: * line 492 of /lib/dml/moodle_database.php: ddl_change_structure_exception thrown

* line 277 of /lib/dml/oci_native_moodle_database.php: call to moodle_database->query_end()

* line 896 of /lib/dml/oci_native_moodle_database.php: call to oci_native_moodle_database->query_end()

* line 77 of /lib/ddl/database_manager.php: call to oci_native_moodle_database->change_database_structure()

* line 758 of /lib/ddl/database_manager.php: call to database_manager->execute_sql_arr()

* line 2263 of /lib/db/upgrade.php: call to database_manager->add_key()

* line 1875 of /lib/upgradelib.php: call to xmldb_main_upgrade()

* line 196 of /admin/cli/upgrade.php: call to upgrade_core()

 !!