Database schema issue missing index 'id' (not unique (id))

[ScottVerbeek]

Database PostgreSQL 14.0.

root@2886180ea26f:/var/www/vanilla-401# php admin/cli/check_database_schema.php 
-------------------------------------------------------------------------------
block_grade_me
 * Missing index 'id' (not unique (id)). 
CREATE INDEX mdl_blocgradme_id_ix ON mdl_block_grade_me (id);
-------------------------------------------------------------------------------

Inspecting the table mdl_block_grade_me with psql (PostgreSQL interactive terminal) we see that a index does actually already exist, however instead of the expected name mdl_blocgradme_id_ix it is actually called mdl_blocgradme_id3_ix.

vanilla-401=# \dS+ mdl_block_grade_me
                                                                   Table "public.mdl_block_grade_me"
     Column     |          Type          | Collation | Nullable |                    Default                     | Storage  | Compression | Stats target | Description 
----------------+------------------------+-----------+----------+------------------------------------------------+----------+-------------+--------------+-------------
 id             | bigint                 |           | not null | nextval('mdl_block_grade_me_id_seq'::regclass) | plain    |             |              | 
 itemname       | character varying(255) |           |          |                                                | extended |             |              | 
 itemtype       | character varying(30)  |           | not null | ''::character varying                          | extended |             |              | 
 itemmodule     | character varying(30)  |           |          |                                                | extended |             |              | 
 iteminstance   | bigint                 |           |          |                                                | plain    |             |              | 
 itemsortorder  | bigint                 |           | not null | 0                                              | plain    |             |              | 
 courseid       | bigint                 |           | not null | 0                                              | plain    |             |              | 
 coursename     | character varying(255) |           | not null | ''::character varying                          | extended |             |              | 
 coursemoduleid | bigint                 |           | not null | 0                                              | plain    |             |              | 
Indexes:
    "mdl_blocgradme_id_pk" PRIMARY KEY, btree (id)
    "mdl_blocgradme_cou2_ix" btree (coursemoduleid)
    "mdl_blocgradme_cou_ix" btree (courseid)
    "mdl_blocgradme_couite_ix" btree (courseid, itemmodule)
    "mdl_blocgradme_id3_ix" btree (id)                         <-- NOTE:  The missing index
    "mdl_blocgradme_ite_ix" btree (itemsortorder)
Access method: heap

[ScottVerbeek]

At this point the index appear redundant. db/install.xml specifies a foreign key, however postgres creates a index instead of a constraint (foreign key).

Given this, then the primary key would suffice and the index mdl_blocgradme_id3_ix can be removed. Alternatively the mdl_blocgradme_id_pk is removed and the index mdl_blocgradme_id3_ix is extended to be unique.