igora100

O, mighty and great Mikko !!!
I did it with your help!
It turned out such a request:

	$stringQ = "SELECT * FROM $wpdb->term_relationships tr ";
	$stringQ .= " LEFT JOIN {$wpdb->term_taxonomy} tt ON (tr.term_taxonomy_id=tt.term_taxonomy_id AND tt.taxonomy='product_cat') " ;
	$stringQ .= " LEFT JOIN {$wpdb->terms} t ON (t.term_id=tt.term_id) " ;
	$stringQ .=	" WHERE tr.object_id IN ( " . implode( ',', $arr_find_ID ) . " )";

At the output, I get an array of objects:

[10] => stdClass Object
        (
            [object_id] => 442247
            [term_taxonomy_id] => 23517
            [term_order] => 0
            [term_id] => 23517
            [taxonomy] => product_cat
            [description] => 
            [parent] => 23515
            [count] => 398
            [name] => Смартфоны
            [slug] => smartfony
            [term_group] => 0
        )

Next, I summarize the objects by term_id and everything is ready!
The full time on the whole processing cycle (from the time of the formation of the found objects of the objects before the output of the formed table with the number of items found in each category) with 500 products found. It takes 0.01sec, which is very good and right 40 times faster!!! than using get_the_terms ()

Relevanssi doesn’t know which posts are in which category; it doesn’t need to. If you use a category filter in the search, the filtering is done in the database.

Many thanks, Mikko !
In this case, relavsis still works with its cashe, but does an additional request in the database or not?

get all the categories for those posts directly from the wp_term_relationships database table

Thanks, I’ll try.

Oh….
At the entrance of the relavanssi_compile_search_args () function, everything is fine!
Here we have:

WP_Query Object
(
    [query] => Array
        (
            [s] => камера
            [post_type] => product
            [product_cat] => bytovaya-tehnika
        )

    [query_vars] => Array
        (
            [s] => камера
            [post_type] => product
            [product_cat] => bytovaya-tehnika
...

            [tax_query] => Array
                (
                    [relation] => AND
                    [0] => Array
                        (
                            [taxonomy] => product_visibility
                            [field] => term_taxonomy_id
                            [terms] => Array
                                (
                                    [0] => 6
                                )

                            [operator] => NOT IN
                        )

                )
.....
            [taxonomy] => product_cat
            [term] => bytovaya-tehnika
        )

    [tax_query] => WP_Tax_Query Object
        (
            [queries] => Array
                (
                    [relation] => AND
                    [0] => Array
                        (
                            [taxonomy] => product_visibility
                            [terms] => Array
                                (
                                    [0] => 6
                                )

                            [field] => term_taxonomy_id
                            [operator] => NOT IN
                            [include_children] => 1
                        )

                    [1] => Array
                        (
                            [taxonomy] => product_cat
                            [terms] => Array
                                (
                                    [0] => bytovaya-tehnika
                                )

                            [field] => slug
                            [operator] => IN
                            [include_children] => 1
                        )

                )

            [relation] => AND
            [table_aliases:protected] => Array
                (
                    [0] => wp_term_relationships
                )

            [queried_terms] => Array
                (
                    [product_cat] => Array
                        (
                            [terms] => Array
                                (
                                    [0] => bytovaya-tehnika
                                )

                            [field] => slug
                        )

                )

            [primary_table] => wp_posts
            [primary_id_column] => ID
        )

.....
)

But I have in $query->query_vars['tax_query'] something is, I do not know where it is ….. and it affects the result, because Next, in the relavanssi_compile_search_args () functions, it is from $query->query_vars['tax_query'], and not from $query->tax_query, where I’m fine.

Is 6 the correct taxonomy ID number?

NO!. Coorect = 23166

Or is that some other taxonomy (like WooCommerce stock status)?

Seems to be yes.

It turns out the plugin does not receive additional selection criteria?
Tell me which function of which plugin file it happens, I will try to “catch” this moment.