Global search '*' causes loads of aborted connections... I mean
2020-08-15 2:53:58 140273206434560 [Warning] Aborted connection 45219 to db: 'db_webqtl' user: 'webqtlout' host: '127.0.0.1' (CLOSE_CONNECTION)
generating 6Mb of log file info.
In fact, every row in the table has a SQL query that does not close the connection properly.
The new xapian search does not use the SQL database at all. Therefore issue may be closed.