Unable to upgrade Confluence with Oracle having several databases on the same db server

Problem

Confluence upgrade from 7.4.1 to 7.13.2 fails if the DB server already has another database with Confluence

Steps to Reproduce

Steps to Reproduce

1. Create two databases test1 and test2 on the same Oracle server.
2. Install Confluence 7.4.1 using test1 database
3. Install a separate instance of Confluence 7.4.1 using test2 database
4. Upgrade the second instance to Confluence 7.13.2

Expected Results

The upgrade finishes successfully.

Actual Results

2021-11-18 08:51:56,566 ERROR [main] [atlassian.confluence.plugin.PluginFrameworkContextListener] launchUpgrades Upgrade failed, application will not start: Upgrade task com.atlassian.confluence.upgrade.upgradetask.DenormalisedSpacePermissionsUpgradeTask@4478a4ff failed during the SCHEMA_UPGRADE phase due to: StatementCallback; uncategorized SQLException for SQL [DROP INDEX denormalised_space_edit_permissions_denorm_space_sid_idx]; SQL state [72000]; error code [2429]; ORA-02429: cannot drop index used for enforcement of unique/primary key
; nested exception is java.sql.SQLException: ORA-02429: cannot drop index used for enforcement of unique/primary key

Workaround

Remove primary key and index from DENORMALISED tables from test2 database:

ALTER TABLE "test2"."DENORMALISED_STATE" DROP PRIMARY KEY;
ALTER TABLE "test2"."DENORMALISED_CONTENT" DROP PRIMARY KEY;
ALTER TABLE "test2"."DENORMALISED_SID" DROP PRIMARY KEY;
ALTER TABLE "test2"."DENORMALISED_SPACE_VIEW_PERMISSIONS" DROP PRIMARY KEY;
ALTER TABLE "test2"."DENORMALISED_SPACE_EDIT_PERMISSIONS" DROP PRIMARY KEY;
ALTER TABLE "test2"."DENORMALISED_CONTENT_VIEW_PERMISSIONS" DROP PRIMARY KEY;

DROP INDEX "test2"."DENORM_CONTENT_SPACE_ID_IDX";
DROP INDEX "test2"."DENORM_CONTENT_PARENT_ID_IDX";
DROP INDEX "test2"."DENORMALISED_SID_NAME_TYPE_UNIQ_IDX";
DROP INDEX "test2"."DENORMALISED_SPACE_VIEW_PERMISSIONS_DENORM_SPACE_SID_IDX";
DROP INDEX "test2"."DENORMALISED_SPACE_EDIT_PERMISSIONS_DENORM_SPACE_SID_IDX";
DROP INDEX "test2"."DENORMALISED_CONTENT_VIEW_PERMISSIONS_DENORM_CONTENT_SID_IDX";

Notes