public static function update_last_activity( $user_id, $time ) {
		global $wpdb;

		$table_name = buddypress()->members->table_name_last_activity;

		$activity = self::get_last_activity( $user_id );

		if ( ! empty( $activity[ $user_id ] ) ) {
			$updated = $wpdb->update(
				$table_name,

				// Data to update.
				array(
					'date_recorded' => $time,
				),

				// WHERE.
				array(
					'id' => $activity[ $user_id ]['activity_id'],
				),

				// Data sanitization format.
				array(
					'%s',
				),

				// WHERE sanitization format.
				array(
					'%d',
				)
			);

			// Add new date to existing activity entry for caching.
			$activity[ $user_id ]['date_recorded'] = $time;

		} else {
			$updated = $wpdb->insert(
				$table_name,

				// Data.
				array(
					'user_id'       => $user_id,
					'component'     => buddypress()->members->id,
					'type'          => 'last_activity',
					'action'        => '',
					'content'       => '',
					'primary_link'  => '',
					'item_id'       => 0,
					'date_recorded' => $time,
				),

				// Data sanitization format.
				array(
					'%d',
					'%s',
					'%s',
					'%s',
					'%s',
					'%s',
					'%d',
					'%s',
				)
			);

			// Set up activity array for caching.
			// View the foreach loop in the get_last_activity() method for format.
			$activity = array();
			$activity[ $user_id ] = array(
				'user_id'       => $user_id,
				'date_recorded' => $time,
				'activity_id'   => $wpdb->insert_id,
			);
		}

		// Set cache.
		wp_cache_set( $user_id, $activity[ $user_id ], 'bp_last_activity' );

		/**
		 * Fires when a user's last_activity value has been updated.
		 *
		 * @since 2.7.0
		 *
		 * @param int    $user_id ID of the user.
		 * @param string $time    Last activity timestamp, in 'Y-m-d H:i:s' format.
		 */
		do_action( 'bp_core_user_updated_last_activity', $user_id, $time );

		return $updated;
	}