If the "debug.sql_explain: true" is enabled i.e. in:
| config/default/config.yml
 | 
| # # phpBB's config file (This line is needed because of the packager) | 
| parameters: | 
| debug.load_time: true | 
| debug.sql_explain: true | 
| debug.memory: true | 
| debug.show_errors: true | 
| debug.exceptions: true | 
and you do a normal search with one or more search results, the result page shows in title:
Search found 0 match: test
The variable $total_match_count is allways 0
Proof:
| config/default/config.yml
 | 
| # # phpBB's config file (This line is needed because of the packager) | 
| parameters: | 
| debug.load_time: true | 
| # debug.sql_explain: true | 
| debug.memory: true | 
| debug.show_errors: true | 
| debug.exceptions: true | 
Search result title:
Search found 144 match: test
phpBB 3.3.4
PHP 7.4.9 / 7.4.12
- is related to
- 
                    PHPBB-16902 Improve search results count for MySQL -         
- Unverified Fix
 
-         
- 
                    PHPBB-16622 Search function, if enabled debug.sql_explain and run server mysql 5.6 -         
- Closed
 
-         

