How to avoid a duplicate query from using wp_nav_menu?

Question

My theme need to render 2 menus in homepage. The rest pages only need one. As result is only homepage got duplicate query warning. After tracking down, I found out this was cause by wp_nav_menu. How do I avoid this problem?

Here is the screenshot of my duplication warning:

SELECT t.*, tt.*
FROM wp_terms AS t
INNER JOIN wp_term_taxonomy AS tt
ON t.term_id = tt.term_id
WHERE t.term_id = 163

And its caller:

1. Lucidy\header()
   wp-content/themes/lucidy/engines/linker.php:86
2. Lucidy\render()
   wp-content/themes/lucidy/engines/linker.php:79
3. Lucidy\load()
   wp-content/themes/lucidy/engines/linker.php:48
4. wp_nav_menu()
   wp-includes/nav-menu-template.php:120
5. wp_get_nav_menu_object()
   wp-includes/nav-menu.php:26
6. get_term()
   wp-includes/taxonomy.php:834
7. WP_Term::get_instance()
   wp-includes/class-wp-term.php:131

According to debugger, potential troublemakers are get_term_link and get_term_field. However, I can be very sure that I don't directly use them. It must be called from the wp_nav_menu. The wp_nav_menu is the main suspect because in other page, such as archive page or singular page, I couldn't find any duplication warning.

Is this the core bug? Anyway, how do I avoid it? My theme has been slow recently (up to 0.30s~0.60s rendering time for homepage) so I would like to optimize it very much.

[Update 5-Otc] Sorry, I forgot to share my menu info. I actually has 3 menu locations and 2 of them are placed in homepage. At homepage I use wp_nav_menu 2 times.

I register those in functions.php:

register_nav_menus([
    'menu_col' => __('Menu Column', 'lucidy'),
    'menu_list' => __('Menu List', 'lucidy'),
    'menu_bar' => __('Menu Bar', 'lucidy')
]);

Answer 1

You'd avoid it by creating another menu and menu location. You can do this with a widget area or whatever. Then only call the menu if the page is the home page with is_home() or is_front_page() if it is a page.

Here's from twenty seventeen as an example.

register_nav_menus(
    array(
        'top'    => __( 'Top Menu', 'twentyseventeen' ),
        'social' => __( 'Social Links Menu', 'twentyseventeen' ),
    )
);

and then it's called like:

<?php if ( has_nav_menu( 'top' ) ) : ?>
    <div class="navigation-top">
        <div class="wrap">
            <?php get_template_part( 'template-parts/navigation/navigation', 'top' ); ?>
        </div>

You can pretty much put whatever you want in widget areas though. I use them just incase I wanna stick something else there.

In your situation, menu is the "correct" way to do it though.