Options, Meta APIs: Introduce `prime_options()` to load multiple options with a single database request.

WordPress's `get_option()` function generally relies on making individual database requests for each option, however with the majority of options (in most cases) being autoloaded, i.e. fetched once with a single database request and then stored in (memory) cache.

As part of a greater effort to reduce the amount of options that are unnecessarily autoloaded, this changeset introduces an alternative way to retrieve multiple options in a performant manner, with a single database request. This provides a reasonable alternative for e.g. plugins that use several options which only need to be loaded in a few specific screens.

Specifically, this changeset introduces the following functions:
* `prime_options( $options )` is the foundation to load multiple specific options with a single database request. Only options that aren't already cached (in `alloptions` or an individual cache) are retrieved from the database.
* `prime_options_by_group( $option_group )` is a convenience wrapper function for the above which allows to prime all options of a specific option group (as configured via `register_setting()`).
* `get_options( $options )` is another wrapper function which first primes the requested options and then returns them in an associative array, calling `get_option()` for each of them.

Props mukesh27, joemcgill, costdev, olliejones.
Fixes #58962.

Built from https://develop.svn.wordpress.org/trunk@56445


git-svn-id: http://core.svn.wordpress.org/trunk@55957 1a063a9b-81f0-0310-95a4-ce76da25c4cd

wp-includes/option.php

@@ -253,6 +253,117 @@ function get_option( $option, $default_value = false ) {
 	return apply_filters( "option_{$option}", maybe_unserialize( $value ), $option );
 }
 
+/**
+ * Primes specific options into the cache with a single database query.
+ *
+ * Only options that do not already exist in cache will be primed.
+ *
+ * @since 6.4.0
+ *
+ * @global wpdb $wpdb WordPress database abstraction object.
+ *
+ * @param array $options An array of option names to be primed.
+ */
+function prime_options( $options ) {
+	$alloptions     = wp_load_alloptions();
+	$cached_options = wp_cache_get_multiple( $options, 'options' );
+
+	// Filter options that are not in the cache.
+	$options_to_prime = array();
+	foreach ( $options as $option ) {
+		if ( ( ! isset( $cached_options[ $option ] ) || ! $cached_options[ $option ] ) && ! isset( $alloptions[ $option ] ) ) {
+			$options_to_prime[] = $option;
+		}
+	}
+
+	// Bail early if there are no options to be primed.
+	if ( empty( $options_to_prime ) ) {
+		return;
+	}
+
+	global $wpdb;
+	$results = $wpdb->get_results(
+		$wpdb->prepare(
+			sprintf(
+				"SELECT option_name, option_value FROM $wpdb->options WHERE option_name IN (%s)",
+				implode( ',', array_fill( 0, count( $options_to_prime ), '%s' ) )
+			),
+			$options_to_prime
+		)
+	);
+
+	$options_found = array();
+	foreach ( $results as $result ) {
+		$options_found[ $result->option_name ] = maybe_unserialize( $result->option_value );
+	}
+	wp_cache_set_multiple( $options_found, 'options' );
+
+	// If all options were found, no need to update `notoptions` cache.
+	if ( count( $options_found ) === count( $options_to_prime ) ) {
+		return;
+	}
+
+	$options_not_found = array_diff( $options_to_prime, array_keys( $options_found ) );
+
+	$notoptions = wp_cache_get( 'notoptions', 'options' );
+
+	if ( ! is_array( $notoptions ) ) {
+		$notoptions = array();
+	}
+
+	// Add the options that were not found to the cache.
+	$update_notoptions = false;
+	foreach ( $options_not_found as $option_name ) {
+		if ( ! isset( $notoptions[ $option_name ] ) ) {
+			$notoptions[ $option_name ] = true;
+			$update_notoptions          = true;
+		}
+	}
+
+	// Only update the cache if it was modified.
+	if ( $update_notoptions ) {
+		wp_cache_set( 'notoptions', $notoptions, 'options' );
+	}
+}
+
+/**
+ * Primes all options registered with a specific option group.
+ *
+ * @since 6.4.0
+ *
+ * @global array $new_allowed_options
+ *
+ * @param string $option_group The option group to prime options for.
+ */
+function prime_options_by_group( $option_group ) {
+	global $new_allowed_options;
+
+	if ( isset( $new_allowed_options[ $option_group ] ) ) {
+		prime_options( $new_allowed_options[ $option_group ] );
+	}
+}
+
+/**
+ * Retrieves multiple options.
+ *
+ * Options are primed as necessary first in order to use a single database query at most.
+ *
+ * @since 6.4.0
+ *
+ * @param array $options An array of option names to retrieve.
+ * @return array An array of key-value pairs for the requested options.
+ */
+function get_options( $options ) {
+	prime_options( $options );
+
+	$result = array();
+	foreach ( $options as $option ) {
+		$result[ $option ] = get_option( $option );
+	}
+
+	return $result;
+}
+
 /**
  * Protects WordPress special option from being modified.
  *

wp-includes/version.php

@@ -16,7 +16,7 @@
  *
  * @global string $wp_version
  */
-$wp_version = '6.4-alpha-56444';
+$wp_version = '6.4-alpha-56445';
 
 /**
  * Holds the WordPress DB revision, increments when changes are made to the WordPress DB schema.