Database index `fs_storage_path_prefix` is not created with Postgresql

⚠️ This issue respects the following points: ⚠️

• This is a bug, not a question or a configuration/webserver/proxy issue.
• This issue is not already reported on Github (I've searched it).
• Nextcloud Server is up to date. See Maintenance and Release Schedule for supported versions.
• Nextcloud Server is running on 64bit capable CPU, PHP and OS.
• I agree to follow Nextcloud's Code of Conduct.

Bug description

About PostgreSQL support.

Considering this line of code : https://github.com/nextcloud/server/blob/master/core/Command/Db/AddMissingIndices.php#L175

When installing Nextcloud, database index is not created with postgresql database to avoid any later issues (according this commit: https://github.com/nextcloud/server/commit/695326534c18749f36e9172e7b7345824213ee60

According to our research, the missing index is in the oc_filecache table.

With MySQL/Mariadb in database, the index is indeed created by Nextcloud and is called fs_storage_path_prefix. But he is
therefore not created with PostgreSQL

We think that performance issue could occur specially when Cronjob is running with huge database.

Could Nextcloud consider solving this annoying issue ?

The commit talks about extra parameters in dbal driver, could we have any explanations about ?

Expected behavior

Expect to have database index created.

Nextcloud Server version

25

Database engine version

PostgreSQL

Start in core/Command/Db/AddMissingIndices.php around line 175 and review commit 695326534c18749f36e9172e7b7345824213ee60. Compare how the fs_storage_path_prefix index is handled for MySQL/MariaDB and PostgreSQL on the oc_filecache table. Done means PostgreSQL installations create the index without the later issues described by the commit.