Issues with Duplicate Keys and Indexes during OJS Upgrade 3.3.0.15 to latest

Description of the problem: I am attempting to upgrade Open Journal Systems (OJS) 3.3.0.15 to 3.4.0.5 but continually encounter errors related to duplicate keys and indexes. Specifically, the errors are as follows:

  1. Duplicate key ‘review_form_responses_unique’:

SQLSTATE[42000]: Syntax error or access violation: 1061 Duplicate key name ‘review_form_responses_unique’


2. Duplicate key 'review_round_files_unique':

SQLSTATE[42000]: Syntax error or access violation: 1061 Duplicate key name ‘review_round_files_unique’


3. Duplicate key 'review_files_unique':

SQLSTATE[42000]: Syntax error or access violation: 1061 Duplicate key name ‘review_files_unique’


What I have already tried:

I attempted to delete the problematic indexes using SQL commands such as:

ALTER TABLE review_form_responses DROP INDEX review_form_responses_unique;
ALTER TABLE review_round_files DROP INDEX review_round_files_unique;
ALTER TABLE review_files DROP INDEX review_files_unique;


Despite deleting these indexes, they are recreated during the upgrade process, causing the same errors to reoccur.

Request for Assistance:

1. Permanent deletion or correction of the duplicate keys so that they are not recreated during the upgrade.
2. Guidance on properly setting up the database to ensure the upgrade proceeds without errors.
3. Any additional steps I should take to ensure the database is in a correct state before performing the upgrade.

Thank you in advance for your help!