app/migrations/Version20211026152443.php

<?php

declare(strict_types=1);

namespace Mautic\Migrations;

use Doctrine\DBAL\Schema\Schema;
use Mautic\CoreBundle\Doctrine\PreUpAssertionMigration;

final class Version20211026152443 extends PreUpAssertionMigration
{
    protected function preUpAssertions(): void
    {
        $this->skipAssertion(
            fn (Schema $schema) => $schema->getTable($this->getTableName())->hasIndex($this->getIndexName()),
            "Index {$this->getIndexName()} already exists"
        );
    }

    public function up(Schema $schema): void
    {
        $this->addSql("CREATE INDEX {$this->getIndexName()} ON {$this->getTableName()} (`object`, `field_order`, `is_published`)");
    }

    public function down(Schema $schema): void
    {
        $this->addSql("DROP INDEX {$this->getIndexName()} ON {$this->getTableName()}");
    }

    private function getTableName(): string
    {
        return "{$this->prefix}lead_fields";
    }

    private function getIndexName(): string
    {
        return "{$this->prefix}idx_object_field_order_is_published";
    }
}