Spring 引导 1.5 到 2 迁移 - Flyway 迁移校验和不匹配

Question

从 1.5 升级到 Spring Boot 2 时，我收到以下错误，尽管 SQL 脚本没有更改：

Migration checksum mismatch for migration version 1
-> Applied to database : 1395032327
-> Resolved locally    : -175919814

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To make sure that the schema upgrade goes smoothly, please follow the following instructions:

First upgrade your 1.5.x Spring Boot application to Flyway 4 (4.2.0 at the time of writing), see the instructions for Maven and Gradle.

Once your schema has been upgraded to Flyway 4, upgrade to Spring Boot 2 and run the migration again to port your application to Flyway 5.

如果您不控制部署并且不能部署应用程序两次（例如，用户下载最新版本的应用程序），这就不容易实现。

问题的原因是什么，解决方案是什么？

Answer 1

校验和算法似乎在版本之间发生了变化。在 Flyway 4、

的（某些）版本中

all checksums are automatically recalculated and updated with the new algorithm on first run (Flyway #253)

我不确定这是否意味着校验和是用两个版本计算的，如果它匹配旧版本用新版本更新，或者这是否意味着它被新版本盲目覆盖。

Flyway 校验和算法：

版本 3 - 超过字节的 crc32：

bytes = resource.loadAsBytes()
...
crc32.update(bytes);

版本 5（不是逐字复制）- crc32 over lines（忽略 CR/LF，并使用 UTF-8 编码）：

BufferedReader bufferedReader = new BufferedReader(new StringReader(resource.loadAsString(configuration.getEncoding())));
[...]
while ((line = bufferedReader.readLine()) != null) {
    crc32.update(line.getBytes("UTF-8"));
}

解决方案

在的答案中提供了多种解决方案。

因为必须避免手动干预，所以我使用 FlywayMigrationStrategy 和 jdbcTemplate 在启动时将校验和从固定已知值更新为 Flyway 5 所需的新固定已知值.

Answer 2

可能最简单的方法是在真正迁移之前执行 flyway.repair()：

@Configuration
public class FlywayRepair {

    @Bean
    public FlywayMigrationStrategy repair() {
        return flyway -> {
            // repair each script checksum 
            flyway.repair();
            // before migration is executed 
            flyway.migrate();
        };
    }
}

缺点是它还删除了失败的迁移。来自 Flyway.repair() Javadoc:

Repairs the Flyway schema history table. This will perform the following actions:

Remove any failed migrations on databases without DDL transactions (User objects left behind must still be cleaned up manually)

Realign the checksums, descriptions and types of the applied migrations with the ones of the available migrations

Spring 引导 1.5 到 2 迁移 - Flyway 迁移校验和不匹配

Spring Boot 1.5 to 2 migration - Flyway migration checksum mismatch

flyway

spring-boot