Describe the bug
I recently upgraded to PostgreSQL 14 backend (Update: This issue also applies to PostgreSQL 12 backend). When I access FreshRSS's "Manage users" configuration page, FreshRSS will automatically send a query

SELECT
pg_total_relation_size('"username_category"')
pg_total_relation_size('"username_feed"')
pg_total_relation_size('"username_entry"')
pg_total_relation_size('"username_entrytmp"')
pg_total_relation_size('"username_tag"')
pg_total_relation_size('"username_entrytag"')

to the database to retrieve database sizes. However, this SQL statement seems to contain syntax errors.

From PostgreSQL 14's log output:

2022-05-19 09:59:39.366 UTC [220] ERROR:  syntax error at or near "(" at character 76
2022-05-19 09:59:39.366 UTC [220] STATEMENT:  SELECT
     pg_total_relation_size('"username_category"')
     pg_total_relation_size('"username_feed"')

...

near "(" at character 76 indicates the second "(". Seems like there are missing "+" operators between the PostgreSQL functions.

To Reproduce
Steps to reproduce the behavior:

1. Deploy and Initialize FreshRSS with a PostgreSQL 14 database using Docker
2. Log in to FreshRSS WebUI as an administrator
3. Navigate to Settings - Manage users
4. Monitor the log of the PostgreSQL 14.3 database

Expected behavior
A successful SQL query returns the size of relations.

Screenshots
The failed SQL query results in zero "Database size":

Environment information (please complete the following information):

• Device: N.A.
• OS: Debian 11.3
• Browser: Firefox 100
• FreshRSS version: 1.19.2
• Database version: PostgreSQL 14.3 ( official PostgreSQL docker image library/postgres:14 )
• PHP version: PHP 7.4.25 (in freshrss/freshrss official Docker image)
• Installation type: Docker ( freshrss/freshrss )

Additional context

Related code (DatabaseDAOPGSQL) seems to be here:

but I don't know why the "+" are missing in the database's log.