I have the last version of plugin (v1.26.67).
The table wpftsi_index have 650K rows
The table wpftsi_vectors have 34M (millions) rows
I use mysql8 on a server with 12 core and 64GB of memory.
When the user make a search with more then 2 or 3 terms the db server hang.
There's a way to simplify the JOIN query and avoid the LEFT JOIN for each search term?

Something like:
where (w1.word like "matisse%" OR w1.word like "picasso%")

Now the plugin make a LEFT JOIN for each search term:
LEFT JOIN ( select .... where (w1.word like "matisse%") group by ds1.id order by NULL ) t1 on t1.id = tbase.id
LEFT JOIN ( select ... where (w1.word like "picasso%") group by ds1.id order by NULL ) t2 on t2.id = tbase.id
where ....

Thanks.
Giovanni.