Object Cache + Query Batching — Enterprise Performance

Field Forge integrates with WordPress’s object cache API (wp_cache_*) for fast field value lookups, plus provides a batch_load() API for eliminating N+1 query problems on large sites. Combined with custom table storage, this makes Field Forge the fastest WordPress custom fields plugin on high-traffic sites.

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WordPress object cache basics

WordPress’s wp_cache_* functions provide a caching layer that sits between your code and the database. By default, WordPress uses a per-request in-memory cache (cleared at the end of each request). With a persistent object cache backend like Redis or Memcached, the cache survives between requests — subsequent pageviews hit the cache instead of the database.

On a high-traffic site with Redis:

• First pageview: fetches from database, stores in Redis
• Second pageview (same data): hits Redis, skips database entirely
• Third pageview: hits Redis
• …

For read-heavy workloads, this is a 10–100x performance improvement.

Field Forge and object cache

Every field value read in Field Forge goes through the object cache:

// Inside Field Forge's get_field() implementation (simplified)
$cached = wp_cache_get($cache_key, 'fieldforge');
if ($cached !== false) {
    return $cached;
}

$value = $this->fetch_from_database($post_id, $field_name);
wp_cache_set($cache_key, $value, 'fieldforge', 3600);
return $value;

• Cache key format — fieldforge:{post_id}:{field_name}
• Cache group — fieldforge (separate from other plugins)
• Expiration — 1 hour default, configurable via filter
• Cache miss handling — falls through to database query, then caches result

Cache invalidation

When a field value is updated or deleted, Field Forge automatically invalidates the relevant cache entries:

// Inside update_field() (simplified)
$this->save_to_database($post_id, $field_name, $value);
wp_cache_delete("fieldforge:{$post_id}:{$field_name}", 'fieldforge');

Invalidation is:

• Immediate — on save, the old cache entry is deleted
• Precise — only the specific field’s cache is invalidated, not the whole post’s
• Hooked — plugins can add custom invalidation logic via fieldforge/cache/invalidate hook

Supported cache backends

Field Forge works with any WordPress object cache backend:

Redis

Most common for managed WordPress hosting. Free plugins: “Redis Object Cache” or “W3 Total Cache” with Redis enabled. Provides persistent caching across requests.

Memcached

Older but still supported. Plugins: “Memcached” or “W3 Total Cache.”

APCu

Single-server caching that’s faster than Redis/Memcached for lower-traffic sites (no network hop). Plugins: “APCu Object Cache.”

Default in-memory cache

If no persistent object cache backend is installed, Field Forge falls back to WordPress’s default in-request cache. Caching still happens within a single pageview, but not between requests. Works everywhere, zero configuration.

Batch loading

For archive pages and list views where you’re rendering many posts at once, Field Forge provides a batch_load() API that fetches custom fields for multiple posts in a single SQL query:

$post_ids = [1, 2, 3, 4, 5, 6, 7, 8, 9, 10];
FieldForge::batch_load($post_ids);

// All subsequent get_field() calls on these post IDs hit the cache
foreach ($post_ids as $id) {
    $hero_title = get_field('hero_title', $id);  // Cache hit
    $hero_image = get_field('hero_image', $id);  // Cache hit
}

Without batch_load(), the above would fire 20 separate SQL queries (10 posts × 2 fields each). With batch loading, it’s 1 query.

Automatic preloading

Field Forge hooks into WordPress’s the_posts filter to run batch loading automatically on any query that returns multiple posts:

// Field Forge's internal hook
add_filter('the_posts', function($posts) {
    if (!empty($posts)) {
        $post_ids = wp_list_pluck($posts, 'ID');
        FieldForge::batch_load($post_ids);
    }
    return $posts;
});

Archive pages, search results, category listings, and REST API list endpoints all benefit automatically. No code changes needed in your theme.

Explicit batch loading for custom queries

For WP_Query calls in custom templates, you can explicitly batch-load after the query:

$query = new WP_Query([
    'post_type' => 'product',
    'posts_per_page' => 30,
    'category_name' => 'featured',
]);

// Batch load custom fields for all 30 products in one query
if ($query->have_posts()) {
    $post_ids = wp_list_pluck($query->posts, 'ID');
    FieldForge::batch_load($post_ids);
}

// Now rendering the loop is cache-hit only
while ($query->have_posts()) : $query->the_post();
    $price = get_field('price');        // Cache hit
    $sku = get_field('sku');            // Cache hit
    $features = get_field('features');  // Cache hit
endwhile;

Performance comparison

On a test site with 10,000 posts, 15 custom fields per post:

Without object cache

With Redis object cache (warm cache)

With Redis object cache + batch_load on cold cache

The combination of object cache and batch loading is dramatic on high-traffic sites.

Monitoring cache performance

Field Forge provides WP-CLI commands for monitoring cache performance:

# Show cache stats
wp fieldforge cache stats

# Output:
# Cache hits:    94.3%
# Cache misses:  5.7%
# Avg hit time:  0.2ms
# Avg miss time: 8ms

For sites where cache hit rate is low (below 80%), investigate:

• Is the persistent cache backend actually running?
• Is cache invalidation too aggressive (clearing on every save)?
• Are post types / field groups configured correctly?

Filter customization

Change cache expiration

add_filter('fieldforge/cache/expiration', function($seconds) {
    return DAY_IN_SECONDS;  // Cache for 24 hours
});

Disable caching for specific field groups

add_filter('fieldforge/cache/should_cache', function($should_cache, $field_group) {
    if ($field_group === 'frequently-changing-group') {
        return false;
    }
    return $should_cache;
}, 10, 2);

Custom invalidation logic

add_action('fieldforge/cache/invalidate', function($post_id, $field_name) {
    // Also invalidate related data
    wp_cache_delete("my_custom_cache:{$post_id}", 'my_plugin');
}, 10, 2);

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Object cache integration and batch loading are in every version of Field Forge, including the free one.