Merge pull request #17895 from woocommerce/update/use-post-author-for-customer-id

Use post_author instead of the post meta '_customer_user'

includes/admin/list-tables/class-wc-admin-list-table-orders.php

@@ -772,16 +772,23 @@ class WC_Admin_List_Table_Orders extends WC_Admin_List_Table {
 
 		// Filter the orders by the posted customer.
 		if ( ! empty( $_GET['_customer_user'] ) ) { // WPCS: input var ok.
+			$customer_id = (int) $_GET['_customer_user'];  // WPCS: input var ok, sanitization ok.
+
+			// On WC 3.5.0 the ID of the user that placed the order was moved from the post meta _customer_user to the post_author field in the wp_posts table.
+			if ( version_compare( get_option( 'woocommerce_db_version' ), '3.5.0', '>=' ) ) {
+				$query_vars['author'] = $customer_id;
+			} else {
 				// @codingStandardsIgnoreStart
 				$query_vars['meta_query'] = array(
 					array(
 						'key'     => '_customer_user',
-					'value' => (int) $_GET['_customer_user'], // WPCS: input var ok, sanitization ok.
+						'value'   => $customer_id,
 						'compare' => '=',
 					),
 				);
 				// @codingStandardsIgnoreEnd
 			}
+		}
 
 		// Sorting.
 		if ( isset( $query_vars['orderby'] ) ) {

includes/admin/reports/class-wc-report-customers.php

@@ -69,9 +69,7 @@ class WC_Report_Customers extends WC_Admin_Report {
 	 * Output customers vs guests chart.
 	 */
 	public function customers_vs_guests() {
-
+		$customer_args = array(
-		$customer_order_totals = $this->get_order_report_data(
-			array(
 			'data'         => array(
 				'ID' => array(
 					'type'     => 'post_data',
@@ -79,36 +77,48 @@ class WC_Report_Customers extends WC_Admin_Report {
 					'name'     => 'total_orders',
 				),
 			),
-				'where_meta'   => array(
+			'filter_range' => true,
+		);
+		$guest_args    = $customer_args;
+
+		// On WC 3.5.0 the ID of the user that placed the order was moved from the post meta _customer_user to the post_author field in the wp_posts table.
+		if ( version_compare( get_option( 'woocommerce_db_version' ), '3.5.0', '>=' ) ) {
+			$customer_args['where'] = array(
+				array(
+					'key'      => 'post_author',
+					'value'    => '0',
+					'operator' => '>',
+				),
+			);
+
+			$guest_args['where'] = array(
+				array(
+					'key'      => 'post_author',
+					'value'    => '0',
+					'operator' => '=',
+				),
+			);
+		} else {
+			$customer_args['where_meta'] = array(
 				array(
 					'meta_key'   => '_customer_user',
 					'meta_value' => '0',
 					'operator'   => '>',
 				),
-				),
-				'filter_range' => true,
-			)
 			);
 
-		$guest_order_totals = $this->get_order_report_data(
+			$guest_args['where_meta'] = array(
-			array(
-				'data'         => array(
-					'ID' => array(
-						'type'     => 'post_data',
-						'function' => 'COUNT',
-						'name'     => 'total_orders',
-					),
-				),
-				'where_meta'   => array(
 				array(
 					'meta_key'   => '_customer_user',
 					'meta_value' => '0',
 					'operator'   => '=',
 				),
-				),
-				'filter_range' => true,
-			)
 			);
+		}
+
+		$customer_order_totals = $this->get_order_report_data( $customer_args );
+		$guest_order_totals = $this->get_order_report_data( $guest_args );
+
 		?>
 		<div class="chart-container">
 			<div class="chart-placeholder customers_vs_guests pie-chart" style="height:200px"></div>
@@ -246,8 +256,7 @@ class WC_Report_Customers extends WC_Admin_Report {
 	public function get_main_chart() {
 		global $wp_locale;
 
-		$customer_orders = $this->get_order_report_data(
+		$customer_args = array(
-			array(
 			'data'         => array(
 				'ID'        => array(
 					'type'     => 'post_data',
@@ -260,47 +269,50 @@ class WC_Report_Customers extends WC_Admin_Report {
 					'name'     => 'post_date',
 				),
 			),
-				'where_meta'   => array(
+			'group_by'     => $this->group_by_query,
+			'order_by'     => 'post_date ASC',
+			'query_type'   => 'get_results',
+			'filter_range' => true,
+		);
+		$guest_args    = $customer_args;
+
+		// On WC 3.5.0 the ID of the user that placed the order was moved from the post meta _customer_user to the post_author field in the wp_posts table.
+		if ( version_compare( get_option( 'woocommerce_db_version' ), '3.5.0', '>=' ) ) {
+			$customer_args['where'] = array(
+				array(
+					'key'      => 'post_author',
+					'value'    => '0',
+					'operator' => '>',
+				),
+			);
+
+			$guest_args['where'] = array(
+				array(
+					'key'      => 'post_author',
+					'value'    => '0',
+					'operator' => '=',
+				),
+			);
+		} else {
+			$customer_args['where_meta'] = array(
 				array(
 					'meta_key'   => '_customer_user',
 					'meta_value' => '0',
 					'operator'   => '>',
 				),
-				),
-				'group_by'     => $this->group_by_query,
-				'order_by'     => 'post_date ASC',
-				'query_type'   => 'get_results',
-				'filter_range' => true,
-			)
 			);
 
-		$guest_orders = $this->get_order_report_data(
+			$guest_args['where_meta'] = array(
-			array(
-				'data'         => array(
-					'ID'        => array(
-						'type'     => 'post_data',
-						'function' => 'COUNT',
-						'name'     => 'total_orders',
-					),
-					'post_date' => array(
-						'type'     => 'post_data',
-						'function' => '',
-						'name'     => 'post_date',
-					),
-				),
-				'where_meta'   => array(
 				array(
 					'meta_key'   => '_customer_user',
 					'meta_value' => '0',
 					'operator'   => '=',
 				),
-				),
-				'group_by'     => $this->group_by_query,
-				'order_by'     => 'post_date ASC',
-				'query_type'   => 'get_results',
-				'filter_range' => true,
-			)
 			);
+		}
+
+		$customer_orders = $this->get_order_report_data( $customer_args );
+		$guest_orders = $this->get_order_report_data( $guest_args );
 
 		$signups         = $this->prepare_chart_data( $this->customers, 'user_registered', '', $this->chart_interval, $this->start_date, $this->chart_groupby );
 		$customer_orders = $this->prepare_chart_data( $customer_orders, 'post_date', 'total_orders', $this->chart_interval, $this->start_date, $this->chart_groupby );

includes/api/class-wc-rest-orders-controller.php

@@ -365,6 +365,10 @@ class WC_REST_Orders_Controller extends WC_REST_Legacy_Orders_Controller {
 		}
 
 		if ( isset( $request['customer'] ) ) {
+			// On WC 3.5.0 the ID of the user that placed the order was moved from the post meta _customer_user to the post_author field in the wp_posts table.
+			if ( version_compare( get_option( 'woocommerce_db_version' ), '3.5.0', '>=' ) ) {
+				$args['author'] = $request['customer'];
+			} else {
 				if ( ! empty( $args['meta_query'] ) ) {
 					$args['meta_query'] = array(); // WPCS: slow query ok.
 				}
@@ -375,6 +379,7 @@ class WC_REST_Orders_Controller extends WC_REST_Legacy_Orders_Controller {
 					'type'  => 'NUMERIC',
 				);
 			}
+		}
 
 		// Search by product.
 		if ( ! empty( $request['product'] ) ) {

includes/api/v1/class-wc-rest-orders-controller.php

@@ -404,8 +404,12 @@ class WC_REST_Orders_V1_Controller extends WC_REST_Posts_Controller {
 		}
 
 		if ( isset( $request['customer'] ) ) {
+			// On WC 3.5.0 the ID of the user that placed the order was moved from the post meta _customer_user to the post_author field in the wp_posts table.
+			if ( version_compare( get_option( 'woocommerce_db_version' ), '3.5.0', '>=' ) ) {
+				$args['author'] = $request['customer'];
+			} else {
 				if ( ! empty( $args['meta_query'] ) ) {
-				$args['meta_query'] = array();
+					$args['meta_query'] = array(); // WPCS: slow query ok.
 				}
 
 				$args['meta_query'][] = array(
@@ -414,6 +418,7 @@ class WC_REST_Orders_V1_Controller extends WC_REST_Posts_Controller {
 					'type'  => 'NUMERIC',
 				);
 			}
+		}
 
 		// Search by product.
 		if ( ! empty( $request['product'] ) ) {

includes/class-wc-background-updater.php

@@ -132,4 +132,13 @@ class WC_Background_Updater extends WC_Background_Process {
 		WC_Install::update_db_version();
 		parent::complete();
 	}
+
+	/**
+	 * See if the batch limit has been exceeded.
+	 *
+	 * @return bool
+	 */
+	public function is_memory_exceeded() {
+		return $this->memory_exceeded();
+	}
 }

includes/class-wc-install.php

@@ -109,6 +109,10 @@ class WC_Install {
 			'wc_update_343_cleanup_foreign_keys',
 			'wc_update_343_db_version',
 		),
+		'3.5.0' => array(
+			'wc_update_350_order_customer_id',
+			'wc_update_350_db_version',
+		),
 	);
 
 	/**

includes/class-woocommerce.php

@@ -20,7 +20,7 @@ final class WooCommerce {
 	 *
 	 * @var string
 	 */
-	public $version = '3.4.0';
+	public $version = '3.5.0';
 
 	/**
 	 * The single instance of the class.

includes/data-stores/abstract-wc-order-data-store-cpt.php

@@ -67,7 +67,7 @@ abstract class Abstract_WC_Order_Data_Store_CPT extends WC_Data_Store_WP impleme
 					'post_type'     => $order->get_type( 'edit' ),
 					'post_status'   => 'wc-' . ( $order->get_status( 'edit' ) ? $order->get_status( 'edit' ) : apply_filters( 'woocommerce_default_order_status', 'pending' ) ),
 					'ping_status'   => 'closed',
-					'post_author'   => 1,
+					'post_author'   => is_callable( array( $order, 'get_customer_id' ) ) ? $order->get_customer_id() : 0,
 					'post_title'    => $this->get_post_title(),
 					'post_password' => uniqid( 'order_' ),
 					'post_parent'   => $order->get_parent_id( 'edit' ),
@@ -139,7 +139,7 @@ abstract class Abstract_WC_Order_Data_Store_CPT extends WC_Data_Store_WP impleme
 		$changes = $order->get_changes();
 
 		// Only update the post when the post data changes.
-		if ( array_intersect( array( 'date_created', 'date_modified', 'status', 'parent_id', 'post_excerpt' ), array_keys( $changes ) ) ) {
+		if ( array_intersect( array( 'date_created', 'date_modified', 'status', 'parent_id', 'post_excerpt', 'customer_id' ), array_keys( $changes ) ) ) {
 			$post_data = array(
 				'post_date'         => gmdate( 'Y-m-d H:i:s', $order->get_date_created( 'edit' )->getOffsetTimestamp() ),
 				'post_date_gmt'     => gmdate( 'Y-m-d H:i:s', $order->get_date_created( 'edit' )->getTimestamp() ),
@@ -148,6 +148,7 @@ abstract class Abstract_WC_Order_Data_Store_CPT extends WC_Data_Store_WP impleme
 				'post_excerpt'      => $this->get_post_excerpt( $order ),
 				'post_modified'     => isset( $changes['date_modified'] ) ? gmdate( 'Y-m-d H:i:s', $order->get_date_modified( 'edit' )->getOffsetTimestamp() ) : current_time( 'mysql' ),
 				'post_modified_gmt' => isset( $changes['date_modified'] ) ? gmdate( 'Y-m-d H:i:s', $order->get_date_modified( 'edit' )->getTimestamp() ) : current_time( 'mysql', 1 ),
+				'post_author'       => is_callable( array( $order, 'get_customer_id' ) ) ? $order->get_customer_id() : 0,
 			);
 
 			/**
@@ -165,12 +166,27 @@ abstract class Abstract_WC_Order_Data_Store_CPT extends WC_Data_Store_WP impleme
 				wp_update_post( array_merge( array( 'ID' => $order->get_id() ), $post_data ) );
 			}
 			$order->read_meta_data( true ); // Refresh internal meta data, in case things were hooked into `save_post` or another WP hook.
+
+			// If customer changed, update any downloadable permissions.
+			if ( in_array( 'customer_id', $changes ) ) {
+				$this->update_downloadable_permissions( $order );
+			}
 		}
 		$this->update_post_meta( $order );
 		$order->apply_changes();
 		$this->clear_caches( $order );
 	}
 
+	/**
+	 * Update downloadable permissions for a given order.
+	 *
+	 * @param WC_Order $order Order object.
+	 */
+	protected function update_downloadable_permissions( $order ) {
+		$data_store = WC_Data_Store::load( 'customer-download' );
+		$data_store->update_user_by_order_id( $order->get_id(), $order->get_customer_id(), $order->get_billing_email() );
+	}
+
 	/**
 	 * Method to delete an order from the database.
 	 *

includes/data-stores/class-wc-customer-data-store.php

@@ -325,18 +325,27 @@ class WC_Customer_Data_Store extends WC_Data_Store_WP implements WC_Customer_Dat
 	public function get_last_order( &$customer ) {
 		global $wpdb;
 
-		$last_order = $wpdb->get_var(
+		// On WC 3.5.0 the ID of the user that placed the order was moved from the post meta _customer_user to the post_author field in the wp_posts table.
-			// phpcs:disable WordPress.WP.PreparedSQL.NotPrepared
+		if ( version_compare( get_option( 'woocommerce_db_version' ), '3.5.0', '>=' ) ) {
-			"SELECT posts.ID
+			$query = "SELECT ID
+			FROM $wpdb->posts
+			WHERE post_author = '" . esc_sql( $customer->get_id() ) . "'
+			AND   post_type = 'shop_order'
+			AND   post_status IN ( '" . implode( "','", array_map( 'esc_sql', array_keys( wc_get_order_statuses() ) ) ) . "' )
+			ORDER BY ID DESC";
+		} else {
+			$query = "SELECT posts.ID
 			FROM $wpdb->posts AS posts
 			LEFT JOIN {$wpdb->postmeta} AS meta on posts.ID = meta.post_id
 			WHERE meta.meta_key = '_customer_user'
 			AND   meta.meta_value = '" . esc_sql( $customer->get_id() ) . "'
 			AND   posts.post_type = 'shop_order'
 			AND   posts.post_status IN ( '" . implode( "','", array_map( 'esc_sql', array_keys( wc_get_order_statuses() ) ) ) . "' )
-			ORDER BY posts.ID DESC"
+			ORDER BY posts.ID DESC";
-			// phpcs:enable
+		}
-		);
+
+		// phpcs:ignore WordPress.WP.PreparedSQL.NotPrepared
+		$last_order = $wpdb->get_var( $query );
 
 		if ( ! $last_order ) {
 			return false;
@@ -358,17 +367,25 @@ class WC_Customer_Data_Store extends WC_Data_Store_WP implements WC_Customer_Dat
 		if ( '' === $count ) {
 			global $wpdb;
 
-			$count = $wpdb->get_var(
+			// On WC 3.5.0 the ID of the user that placed the order was moved from the post meta _customer_user to the post_author field in the wp_posts table.
-				// phpcs:disable WordPress.WP.PreparedSQL.NotPrepared
+			if ( version_compare( get_option( 'woocommerce_db_version' ), '3.5.0', '>=' ) ) {
-				"SELECT COUNT(*)
+				$query = "SELECT COUNT(*)
+				FROM $wpdb->posts
+				WHERE   post_type = 'shop_order'
+				AND     post_status IN ( '" . implode( "','", array_map( 'esc_sql', array_keys( wc_get_order_statuses() ) ) ) . "' )
+				AND     post_author = " . esc_sql( $customer->get_id() );
+			} else {
+				$query = "SELECT COUNT(*)
 				FROM $wpdb->posts as posts
 				LEFT JOIN {$wpdb->postmeta} AS meta ON posts.ID = meta.post_id
 				WHERE   meta.meta_key = '_customer_user'
 				AND     posts.post_type = 'shop_order'
 				AND     posts.post_status IN ( '" . implode( "','", array_map( 'esc_sql', array_keys( wc_get_order_statuses() ) ) ) . "' )
-				AND     meta_value = '" . esc_sql( $customer->get_id() ) . "'"
+				AND     meta_value = '" . esc_sql( $customer->get_id() ) . "'";
-				// phpcs:enable
+			}
-			);
+
+			// phpcs:ignore WordPress.WP.PreparedSQL.NotPrepared
+			$count = $wpdb->get_var( $query );
 			update_user_meta( $customer->get_id(), '_order_count', $count );
 		}
 
@@ -393,11 +410,18 @@ class WC_Customer_Data_Store extends WC_Data_Store_WP implements WC_Customer_Dat
 			global $wpdb;
 
 			$statuses = array_map( 'esc_sql', wc_get_is_paid_statuses() );
-			$spent    = $wpdb->get_var(
+
-				// phpcs:disable WordPress.WP.PreparedSQL.NotPrepared
+			// On WC 3.5.0 the ID of the user that placed the order was moved from the post meta _customer_user to the post_author field in the wp_posts table.
-				apply_filters(
+			if ( version_compare( get_option( 'woocommerce_db_version' ), '3.5.0', '>=' ) ) {
-					'woocommerce_customer_get_total_spent_query',
+				$query = "SELECT SUM(meta.meta_value)
-					"SELECT SUM(meta2.meta_value)
+					FROM $wpdb->posts as posts
+					LEFT JOIN {$wpdb->postmeta} AS meta ON posts.ID = meta.post_id
+					WHERE   posts.post_author   = '" . esc_sql( $customer->get_id() ) . "'
+					AND     posts.post_type     = 'shop_order'
+					AND     posts.post_status   IN ( 'wc-" . implode( "','wc-", $statuses ) . "' )
+					AND     meta.meta_key      = '_order_total'";
+			} else {
+				$query = "SELECT SUM(meta2.meta_value)
 					FROM $wpdb->posts as posts
 					LEFT JOIN {$wpdb->postmeta} AS meta ON posts.ID = meta.post_id
 					LEFT JOIN {$wpdb->postmeta} AS meta2 ON posts.ID = meta2.post_id
@@ -405,11 +429,11 @@ class WC_Customer_Data_Store extends WC_Data_Store_WP implements WC_Customer_Dat
 					AND     meta.meta_value     = '" . esc_sql( $customer->get_id() ) . "'
 					AND     posts.post_type     = 'shop_order'
 					AND     posts.post_status   IN ( 'wc-" . implode( "','wc-", $statuses ) . "' )
-					AND     meta2.meta_key      = '_order_total'",
+					AND     meta2.meta_key      = '_order_total'";
-					$customer
+			}
-				)
+
-				// phpcs:enable
+			// phpcs:ignore WordPress.WP.PreparedSQL.NotPrepared
-			);
+			$spent = $wpdb->get_var( apply_filters( 'woocommerce_customer_get_total_spent_query', $query, $customer ) );
 
 			if ( ! $spent ) {
 				$spent = 0;

includes/data-stores/class-wc-order-data-store-cpt.php

@@ -107,10 +107,17 @@ class WC_Order_Data_Store_CPT extends Abstract_WC_Order_Data_Store_CPT implement
 			$date_paid = get_post_meta( $id, '_paid_date', true );
 		}
 
+		// On WC 3.5.0 the ID of the user that placed the order was moved from the post meta _customer_user to the post_author field in the wp_posts table.
+		if ( version_compare( get_option( 'woocommerce_db_version' ), '3.5.0', '>=' ) ) {
+			$customer_id = $post_object->post_author;
+		} else {
+			$customer_id = get_post_meta( $id, '_customer_user', true );
+		}
+
 		$order->set_props(
 			array(
 				'order_key'            => get_post_meta( $id, '_order_key', true ),
-				'customer_id'          => get_post_meta( $id, '_customer_user', true ),
+				'customer_id'          => $customer_id,
 				'billing_first_name'   => get_post_meta( $id, '_billing_first_name', true ),
 				'billing_last_name'    => get_post_meta( $id, '_billing_last_name', true ),
 				'billing_company'      => get_post_meta( $id, '_billing_company', true ),
@@ -258,10 +265,9 @@ class WC_Order_Data_Store_CPT extends Abstract_WC_Order_Data_Store_CPT implement
 			update_post_meta( $id, '_shipping_address_index', implode( ' ', $order->get_address( 'shipping' ) ) );
 		}
 
-		// If customer changed, update any downloadable permissions.
+		// If customer email changed, update any downloadable permissions.
-		if ( in_array( 'customer_id', $updated_props, true ) || in_array( 'billing_email', $updated_props, true ) ) {
+		if ( in_array( 'billing_email', $updated_props ) ) {
-			$data_store = WC_Data_Store::load( 'customer-download' );
+			$this->update_downloadable_permissions( $order );
-			$data_store->update_user_by_order_id( $id, $order->get_customer_id(), $order->get_billing_email() );
 		}
 
 		// Mark user account as active.
@@ -645,6 +651,11 @@ class WC_Order_Data_Store_CPT extends Abstract_WC_Order_Data_Store_CPT implement
 			'page'           => 'paged',
 		);
 
+		// On WC 3.5.0 the ID of the user that placed the order was moved from the post meta _customer_user to the post_author field in the wp_posts table.
+		if ( version_compare( get_option( 'woocommerce_db_version' ), '3.5.0', '>=' ) ) {
+			$key_mapping['customer_id'] = 'author';
+		}
+
 		foreach ( $key_mapping as $query_key => $db_key ) {
 			if ( isset( $query_vars[ $query_key ] ) ) {
 				$query_vars[ $db_key ] = $query_vars[ $query_key ];

includes/wc-update-functions.php

@@ -1835,3 +1835,130 @@ function wc_update_343_cleanup_foreign_keys() {
 function wc_update_343_db_version() {
 	WC_Install::update_db_version( '3.4.3' );
 }
+
+/**
+ * Copy order customer_id from post meta to post_author and set post_author to 0 for refunds.
+ *
+ * Two different strategies are used to copy data depending if the update is being executed from
+ * the command line or not. If `wp wc update` is used to update the database, this function
+ * copies data in a single go that is faster but uses more resources. If the databse update was
+ * triggered from the wp-admin, this function copies data in batches which is slower but uses
+ * few resources and thus is less likely to fail on smaller servers.
+ *
+ * @param WC_Background_Updater|false $updater Background updater instance or false if function is called from `wp wc update` WP-CLI command.
+ * @return true|void Return true if near memory limit and needs to restart. Return void if update completed.
+ */
+function wc_update_350_order_customer_id( $updater = false ) {
+	global $wpdb;
+
+	$post_types              = (array) apply_filters( 'woocommerce_update_350_order_customer_id_post_types', array( 'shop_order' ) );
+	$post_types_placeholders = implode( ', ', array_fill( 0, count( $post_types ), '%s' ) );
+
+	if ( defined( 'WP_CLI' ) && WP_CLI ) {
+		// If running the update from the command-line, copy data in a single go which is faster but uses more resources.
+		$wpdb->query(
+			'CREATE TEMPORARY TABLE customers_map (post_id BIGINT(20), customer_id BIGINT(20), PRIMARY KEY(post_id))'
+		);
+
+		$wpdb->query(
+			"INSERT IGNORE INTO customers_map (SELECT post_id, meta_value FROM wp_postmeta WHERE meta_key = '_customer_user')"
+		);
+
+		$wpdb->query( 'SET sql_safe_updates=1' );
+
+		$wpdb->query(
+			$wpdb->prepare(
+				"UPDATE wp_posts JOIN customers_map ON wp_posts.ID = customers_map.post_id SET wp_posts.post_author = customers_map.customer_id WHERE post_type IN ({$post_types_placeholders})",  // phpcs:ignore WordPress.WP.PreparedSQL.NotPrepared
+				$post_types
+			)
+		);
+
+		$wpdb->update( $wpdb->posts, array( 'post_author' => 0 ), array( 'post_type' => 'shop_order_refund' ) );
+	} else {
+		// If running the update from the wp-admin, copy data in batches being careful not to use more memory than allowed.
+		$admin_orders_sql = '';
+		$admin_orders     = get_transient( 'wc_update_350_admin_orders' );
+
+		if ( false === $admin_orders ) {
+			// Get the list of orders that we don't want to change as they belong to user ID 1.
+			$admin_orders = $wpdb->get_col(
+				$wpdb->prepare(
+					"SELECT ID FROM wp_posts p
+					INNER JOIN wp_postmeta pm ON p.ID = pm.post_id
+					WHERE post_type IN ({$post_types_placeholders}) AND meta_key = '_customer_user' AND meta_value = 1", // phpcs:ignore WordPress.WP.PreparedSQL.NotPrepared
+					$post_types
+				)
+			);
+
+			// Cache the list of orders placed by the user ID 1 as to large stores this query can be slow.
+			set_transient( 'wc_update_350_admin_orders', $admin_orders, DAY_IN_SECONDS );
+		}
+
+		if ( ! empty( $admin_orders ) ) {
+			$admin_orders_sql .= ' AND ID NOT IN (' . implode( ', ', $admin_orders ) . ') ';
+		}
+
+		// Query to get a batch of orders IDs to change.
+		$query = $wpdb->prepare(
+			// phpcs:disable WordPress.WP.PreparedSQL.NotPrepared
+			"SELECT ID FROM {$wpdb->posts}
+			WHERE post_author = 1 AND post_type IN ({$post_types_placeholders}) $admin_orders_sql
+			LIMIT 1000",
+			$post_types
+			// phpcs:enable
+		);
+
+		while ( true ) {
+			// phpcs:ignore WordPress.WP.PreparedSQL.NotPrepared
+			$orders_to_update = $wpdb->get_col( $query );
+
+			// Exit loop if no more orders to update.
+			if ( ! $orders_to_update ) {
+				break;
+			}
+
+			$orders_meta_data = $wpdb->get_results(
+				// phpcs:ignore WordPress.WP.PreparedSQL.NotPrepared
+				"SELECT post_id, meta_value as customer_id FROM {$wpdb->postmeta} WHERE meta_key = '_customer_user' AND post_id IN (" . implode( ', ', $orders_to_update ) . ')'
+			);
+
+			// Exit loop if no _customer_user metas exist for the list of orders to update.
+			if ( ! $orders_meta_data ) {
+				break;
+			}
+
+			// Update post_author for a batch of orders.
+			foreach ( $orders_meta_data as $order_meta ) {
+				// Stop update execution and re-enqueue it if near memory limit.
+				if ( $updater instanceof WC_Background_Updater && $updater->is_memory_exceeded() ) {
+					return true;
+				}
+
+				$wpdb->update( $wpdb->posts, array( 'post_author' => $order_meta->customer_id ), array( 'ID' => $order_meta->post_id ) );
+			}
+		}
+
+		// Set post_author to 0 instead of 1 on all shop_order_refunds.
+		while ( true ) {
+			// Stop update execution and re-enqueue it if near memory limit.
+			if ( $updater instanceof WC_Background_Updater && $updater->is_memory_exceeded() ) {
+				return true;
+			}
+
+			$updated_rows = $wpdb->query( "UPDATE {$wpdb->posts} SET post_author = 0 WHERE post_type = 'shop_order_refund' LIMIT 1000" );
+
+			if ( ! $updated_rows ) {
+				break;
+			}
+		}
+	}
+
+	wp_cache_flush();
+}
+
+/**
+ * Update DB Version.
+ */
+function wc_update_350_db_version() {
+	WC_Install::update_db_version( '3.5.0' );
+}

includes/wc-user-functions.php

@@ -219,11 +219,15 @@ function wc_customer_bought_product( $customer_email, $user_id, $product_id ) {
 	$result         = get_transient( $transient_name );
 
 	if ( false === $result ) {
-		$customer_data = array( $user_id );
+		$customer_data = array();
 
 		if ( $user_id ) {
 			$user = get_user_by( 'id', $user_id );
 
+			if ( version_compare( get_option( 'woocommerce_db_version' ), '3.5.0', '<' ) ) {
+				$customer_data[] = $user_id;
+			}
+
 			if ( isset( $user->user_email ) ) {
 				$customer_data[] = $user->user_email;
 			}
@@ -240,9 +244,20 @@ function wc_customer_bought_product( $customer_email, $user_id, $product_id ) {
 			return false;
 		}
 
-		$result = $wpdb->get_col(
+		if ( version_compare( get_option( 'woocommerce_db_version' ), '3.5.0', '>=' ) && $user_id ) {
-			"
+			// Since WC 3.5 wp_posts.post_author is used to store the ID of the customer who placed an order.
-			SELECT im.meta_value FROM {$wpdb->posts} AS p
+			$query = "SELECT im.meta_value FROM {$wpdb->posts} AS p
+				INNER JOIN {$wpdb->postmeta} AS pm ON p.ID = pm.post_id
+				INNER JOIN {$wpdb->prefix}woocommerce_order_items AS i ON p.ID = i.order_id
+				INNER JOIN {$wpdb->prefix}woocommerce_order_itemmeta AS im ON i.order_item_id = im.order_item_id
+				WHERE p.post_status IN ( 'wc-" . implode( "','wc-", $statuses ) . "' )
+				AND p.post_author = {$user_id}
+				AND pm.meta_key = '_billing_email'
+				AND im.meta_key IN ( '_product_id', '_variation_id' )
+				AND im.meta_value != 0
+				AND pm.meta_value IN ( '" . implode( "','", $customer_data ) . "' )";
+		} else {
+			$query = "SELECT im.meta_value FROM {$wpdb->posts} AS p
 				INNER JOIN {$wpdb->postmeta} AS pm ON p.ID = pm.post_id
 				INNER JOIN {$wpdb->prefix}woocommerce_order_items AS i ON p.ID = i.order_id
 				INNER JOIN {$wpdb->prefix}woocommerce_order_itemmeta AS im ON i.order_item_id = im.order_item_id
@@ -250,9 +265,10 @@ function wc_customer_bought_product( $customer_email, $user_id, $product_id ) {
 				AND pm.meta_key IN ( '_billing_email', '_customer_user' )
 				AND im.meta_key IN ( '_product_id', '_variation_id' )
 				AND im.meta_value != 0
-			AND pm.meta_value IN ( '" . implode( "','", $customer_data ) . "' )
+				AND pm.meta_value IN ( '" . implode( "','", $customer_data ) . "' )";
-		"
+		}
-		); // WPCS: unprepared SQL ok.
+
+		$result = $wpdb->get_col( $query ); // WPCS: unprepared SQL ok.
 		$result = array_map( 'absint', $result );
 
 		set_transient( $transient_name, $result, DAY_IN_SECONDS * 30 );
@@ -495,7 +511,7 @@ function wc_get_customer_order_count( $user_id ) {
 }
 
 /**
- * Reset _customer_user on orders when a user is deleted.
+ * Reset customer ID on orders when a user is deleted.
  *
  * @param int $user_id User ID.
  */
@@ -508,6 +524,22 @@ function wc_reset_order_customer_id_on_deleted_user( $user_id ) {
 			'meta_value' => $user_id,
 		)
 	); // WPCS: slow query ok.
+
+	$post_types              = (array) apply_filters( 'woocommerce_reset_order_customer_id_post_types', array( 'shop_order' ) );
+	$post_types_placeholders = implode( ', ', array_fill( 0, count( $post_types ), '%s' ) );
+	$query_args              = array_merge( $post_types, array( $user_id ) );
+
+	// Since WC 3.5, the customer ID is stored both in the _customer_user postmeta and in the post_author field.
+	// In future versions of WC, the plan is to use only post_author and stop using _customer_user, but for now
+	// we have to update both places.
+	$wpdb->query(
+		// phpcs:disable WordPress.WP.PreparedSQL.NotPrepared, WordPress.DB.PreparedSQLPlaceholders.UnfinishedPrepare
+		$wpdb->prepare(
+			"UPDATE {$wpdb->posts} SET `post_author` = 0 WHERE post_type IN ({$post_types_placeholders}) AND post_author = %d",
+			$query_args
+		)
+		// phpcs:enable
+	);
 }
 
 add_action( 'deleted_user', 'wc_reset_order_customer_id_on_deleted_user' );