SqlCountCache.php

<?php

namespace Drupal\migrate_sql_count_cache_test\Plugin\migrate\source;

use Drupal\migrate\Plugin\migrate\source\SqlBase;

/**
 * Source plugin for Sql count cache test.
 *
 * @MigrateSource(
 *   id = "sql_count_cache"
 * )
 */
class SqlCountCache extends SqlBase {
    
    /**
     * {@inheritdoc}
     */
    public function fields() {
        return [
            'id' => $this->t('Id'),
        ];
    }
    
    /**
     * {@inheritdoc}
     */
    public function getIds() {
        return [
            'id' => [
                'type' => 'integer',
            ],
        ];
    }
    
    /**
     * {@inheritdoc}
     */
    public function query() {
        return $this->select('source_table', 's')
            ->fields('s', [
            'id',
        ]);
    }

}