Enterprise Search on multisite

After completing the steps to code-enable Enterprise Search for an environment, an Elasticsearch (ES) index must be created for each network site that will be using Enterprise Search for search queries.

When new sites are added to the multisite network, an index will not be automatically created for them.

Create an index for a network site

Create an index for a network site with the wp vip-search index --setup command. Target the specific network site by passing the value of the network site’s ID with the --blog-ids option.

In this command example, an index is created for network site ID 2:

vip @example-app.develop -- wp vip-search index --setup --blog-ids=2

Use Search Dev Tools or the wp vip-search health commands to check that the new index is working as expected.

After an index has been successfully created for the network site, it can be targeted in wp vip-search commands by passing the site address URL in the --url argument. If the --url argument is omitted, the CLI command will target the index of the main site (ID 1).

If a network site has been updated by a SQL database import, use versioning to re-index the site and bring the database and Elasticsearch index back into sync.

Search across network sites

WordPress multisite environments that have Enterprise Search enabled and indexes created for more than one network site can configure search queries to run against multiple indexes.

To configure search to run across more than one site index on a multisite network:

1. Create a “network alias index” for all site indexes that currently exist on the multisite network with the command wp vip-search recreate-network-alias. This command must be repeated to update the network alias index each time a new index is created for a site on the network.

vip @example-app.develop -- wp vip-search recreate-network-alias

2. Define the EP_IS_NETWORK constant as true in vip-config.php.

define( 'EP_IS_NETWORK', true );

3. Using the pre_get_posts method, specify which site indexes on the network will handle search queries with the sites parameter in WP_Query. The accepted values for the sites parameter are current (default), a site ID, an array of site IDs, or all (all site indexes that currently exist in the “network alias index”).

In this code example, the custom function vip_search_across_sites() modifies frontend search queries to run across network site ID 2 and network site ID 3:

add_action( 'pre_get_posts', 'vip_search_across_sites' );
function vip_search_across_sites( $query ) {
	if ( $query->is_search() && $query->is_main_query() ) {
		$query->set( 'sites', array( 2, 3 ) );
	}
}

Alternatively, customizations can be added to the cross-site search configuration via WP_Query. In this code example, a query will perform a search for the keyword “carrot” across network site ID 2 and network site ID 3:

$query = new WP_Query(
	array(
		's' => 'carrot',
		'sites' => array( 2, 3 ), // Search only in site IDs 2 and 3 
		'ep_integrate' => true,
	)
);

Create indexes for all sites on a network

Indexes for all network sites on a multisite environment can be created simultaneously by including the --network-wide option when running the wp vip-search index --setup command.

For example:

vip @example-app.develop -- wp vip-search index --setup --network-wide

This method should only be used if Enterprise Search is necessary and will be actively used by all sites on the network. Creating unused indexes can negatively impact the indexing and revalidation operations triggered by periodic health checks.