清理数据库时 Flyway 卡住（Postgres 11）

Question

我们的应用程序包含不能简单回滚的测试。所以我们决定使用flyway的java API。我们将此方法添加到测试中：

@AfterEach
public void remigrate() {
    flyway.clean();
    flyway.migrate();
}

在日志中我发现只有这个：

2020-06-29 15:20:10.356 DEBUG  [-] 1044 --- [           main] o.f.c.i.s.classpath.ClassPathScanner     : Found resource: db/migration/V0_0_1__database-initialization.sql
2020-06-29 15:20:10.356 DEBUG  [-] 1044 --- [           main] o.f.c.i.s.classpath.ClassPathScanner     : Scanning for classes at classpath:db/migration
2020-06-29 15:20:10.356 DEBUG  [-] 1044 --- [           main] o.f.c.i.c.SqlScriptCallbackFactory       : Scanning for SQL callbacks ...
2020-06-29 15:20:10.356 DEBUG  [-] 1044 --- [           main] o.f.core.internal.util.FeatureDetector   : Spring Jdbc available: true
2020-06-29 15:20:10.361 DEBUG  [-] 1044 --- [           main] o.f.core.internal.command.DbClean        : Cleaning schema "public" ...

此应用程序卡住后。当我尝试选择飞行路线历史表记录时，数据库客户端仅加载。其他表上的选择工作正常，所以我预计 flyway 会在历史表上创建死锁。你知道如何解决它吗？谢谢。

执行器 threaddump 中与 flyway 的 clean 相关的最后一个堆栈跟踪：

{
methodName: "socketRead0",
fileName: "SocketInputStream.java",
lineNumber: -2,
className: "java.net.SocketInputStream",
nativeMethod: true
},
{
methodName: "socketRead",
fileName: "SocketInputStream.java",
lineNumber: 116,
className: "java.net.SocketInputStream",
nativeMethod: false
},
{
methodName: "read",
fileName: "SocketInputStream.java",
lineNumber: 171,
className: "java.net.SocketInputStream",
nativeMethod: false
},
{
methodName: "read",
fileName: "SocketInputStream.java",
lineNumber: 141,
className: "java.net.SocketInputStream",
nativeMethod: false
},
{
methodName: "readMore",
fileName: "VisibleBufferedInputStream.java",
lineNumber: 140,
className: "org.postgresql.core.VisibleBufferedInputStream",
nativeMethod: false
},
{
methodName: "ensureBytes",
fileName: "VisibleBufferedInputStream.java",
lineNumber: 109,
className: "org.postgresql.core.VisibleBufferedInputStream",
nativeMethod: false
},
{
methodName: "read",
fileName: "VisibleBufferedInputStream.java",
lineNumber: 67,
className: "org.postgresql.core.VisibleBufferedInputStream",
nativeMethod: false
},
{
methodName: "receiveChar",
fileName: "PGStream.java",
lineNumber: 321,
className: "org.postgresql.core.PGStream",
nativeMethod: false
},
{
methodName: "processResults",
fileName: "QueryExecutorImpl.java",
lineNumber: 1978,
className: "org.postgresql.core.v3.QueryExecutorImpl",
nativeMethod: false
},
{
methodName: "execute",
fileName: "QueryExecutorImpl.java",
lineNumber: 309,
className: "org.postgresql.core.v3.QueryExecutorImpl",
nativeMethod: false
},
{
methodName: "executeInternal",
fileName: "PgStatement.java",
lineNumber: 446,
className: "org.postgresql.jdbc.PgStatement",
nativeMethod: false
},
{
methodName: "execute",
fileName: "PgStatement.java",
lineNumber: 370,
className: "org.postgresql.jdbc.PgStatement",
nativeMethod: false
},
{
methodName: "executeWithFlags",
fileName: "PgPreparedStatement.java",
lineNumber: 149,
className: "org.postgresql.jdbc.PgPreparedStatement",
nativeMethod: false
},
{
methodName: "execute",
fileName: "PgPreparedStatement.java",
lineNumber: 138,
className: "org.postgresql.jdbc.PgPreparedStatement",
nativeMethod: false
},
{
methodName: "execute",
fileName: "ProxyPreparedStatement.java",
lineNumber: 44,
className: "com.zaxxer.hikari.pool.ProxyPreparedStatement",
nativeMethod: false
},
{
methodName: "execute",
fileName: "HikariProxyPreparedStatement.java",
lineNumber: -1,
className: "com.zaxxer.hikari.pool.HikariProxyPreparedStatement",
nativeMethod: false
},
{
methodName: "invoke",
fileName: null,
lineNumber: -1,
className: "sun.reflect.GeneratedMethodAccessor103",
nativeMethod: false
},
{
methodName: "invoke",
fileName: "DelegatingMethodAccessorImpl.java",
lineNumber: 43,
className: "sun.reflect.DelegatingMethodAccessorImpl",
nativeMethod: false
},
{
methodName: "invoke",
fileName: "Method.java",
lineNumber: 498,
className: "java.lang.reflect.Method",
nativeMethod: false
},
{
methodName: "doExecute",
fileName: "JdbcWrapper.java",
lineNumber: 412,
className: "net.bull.javamelody.JdbcWrapper",
nativeMethod: false
},
{
methodName: "invoke",
fileName: "JdbcWrapper.java",
lineNumber: 137,
className: "net.bull.javamelody.JdbcWrapper$StatementInvocationHandler",
nativeMethod: false
},
{
methodName: "invoke",
fileName: "JdbcWrapper.java",
lineNumber: 294,
className: "net.bull.javamelody.JdbcWrapper$DelegatingInvocationHandler",
nativeMethod: false
},
{
methodName: "execute",
fileName: null,
lineNumber: -1,
className: "com.sun.proxy.$Proxy207",
nativeMethod: false
},
{
methodName: "execute",
fileName: "JdbcTemplate.java",
lineNumber: 215,
className: "org.flywaydb.core.internal.jdbc.JdbcTemplate",
nativeMethod: false
},
{
methodName: "doDrop",
fileName: "PostgreSQLTable.java",
lineNumber: 43,
className: "org.flywaydb.core.internal.database.postgresql.PostgreSQLTable",
nativeMethod: false
},
{
methodName: "drop",
fileName: "SchemaObject.java",
lineNumber: 81,
className: "org.flywaydb.core.internal.database.base.SchemaObject",
nativeMethod: false
},
{
methodName: "doClean",
fileName: "PostgreSQLSchema.java",
lineNumber: 97,
className: "org.flywaydb.core.internal.database.postgresql.PostgreSQLSchema",
nativeMethod: false
},
{
methodName: "clean",
fileName: "Schema.java",
lineNumber: 149,
className: "org.flywaydb.core.internal.database.base.Schema",
nativeMethod: false
},
{
methodName: "call",
fileName: "DbClean.java",
lineNumber: 172,
className: "org.flywaydb.core.internal.command.DbClean$3",
nativeMethod: false
},
{
methodName: "call",
fileName: "DbClean.java",
lineNumber: 169,
className: "org.flywaydb.core.internal.command.DbClean$3",
nativeMethod: false
},
{
methodName: "execute",
fileName: "TransactionTemplate.java",
lineNumber: 74,
className: "org.flywaydb.core.internal.jdbc.TransactionTemplate",
nativeMethod: false
},
{
methodName: "cleanSchema",
fileName: "DbClean.java",
lineNumber: 169,
className: "org.flywaydb.core.internal.command.DbClean",
nativeMethod: false
},
{
methodName: "clean",
fileName: "DbClean.java",
lineNumber: 113,
className: "org.flywaydb.core.internal.command.DbClean",
nativeMethod: false
},
{
methodName: "doClean",
fileName: "Flyway.java",
lineNumber: 1488,
className: "org.flywaydb.core.Flyway",
nativeMethod: false
},
{
methodName: "access$300",
fileName: "Flyway.java",
lineNumber: 85,
className: "org.flywaydb.core.Flyway",
nativeMethod: false
},
{
methodName: "execute",
fileName: "Flyway.java",
lineNumber: 1506,
className: "org.flywaydb.core.Flyway$3",
nativeMethod: false
},
{
methodName: "execute",
fileName: "Flyway.java",
lineNumber: 1499,
className: "org.flywaydb.core.Flyway$3",
nativeMethod: false
},
{
methodName: "execute",
fileName: "Flyway.java",
lineNumber: 1711,
className: "org.flywaydb.core.Flyway",
nativeMethod: false
},
{
methodName: "clean",
fileName: "Flyway.java",
lineNumber: 1499,
className: "org.flywaydb.core.Flyway",
nativeMethod: false
},

Answer 1

好的，现在您知道它在 JDBC 执行期间卡住了。 （我将其添加为答案，因为它太长了无法评论，尽管我承认它可能不能作为一个完整的答案，而是一些旨在帮助您整理这些东西的想法）：

无论如何，下一步就是了解查询的具体内容。所以请找出这个并添加到问题中

有很多方法可以实现：

1. 调试 - 因为线程转储准确地显示了问题所在的行，所以放置一个断点并检查。是的，它有点明显，但仍然在这里列出，因为它可能是最容易做的事情。

2. 用log4jdbc之类的东西包装数据源

3. 在 postgresql 级别：

-- show running queries (pre 9.2)
SELECT procpid, age(clock_timestamp(), query_start), usename, current_query 
FROM pg_stat_activity 
WHERE current_query != '<IDLE>' AND current_query NOT ILIKE '%pg_stat_activity%' 
ORDER BY query_start desc;

-- show running queries (9.2)
SELECT pid, age(clock_timestamp(), query_start), usename, query 
FROM pg_stat_activity 
WHERE query != '<IDLE>' AND query NOT ILIKE '%pg_stat_activity%' 
ORDER BY query_start desc;

为什么要做这一切？因为可能查询生成错误，例如未正确指定模式名称等，值得检查IMO。

我要做的一件重要的事情是确保测试针对没有被其他人使用的专用数据库运行。

所以假设你有一个真正的查询并且看到它很好，我真的会和 DBA 交谈（至少在这里得到 DBA 的建议 - 所以考虑在问题中添加 postgresql 的标签，以便人们熟练掌握数据库可以监控这个问题），因为它不再存在于 java 中。 t 可以是某种锁定（有 ways 可以查看 postgresql 中的锁定，但它是一种高级的东西）。

除此之外，我想提以下几点：

1. 您曾说过您不能回滚事务，而我认为它是“理所当然”的。但是在 PostgreSQL 中，DDL 也是事务的一部分，那么为什么实际上你不能这样做呢？

2. 几年前，当我在 Spring Boot 中使用 PostgreSQL 时，我的团队返回而不是采用基于 Testcontainers 的方法。基本上这允许使用“专有”数据库进行测试，此外，由于该解决方案本质上是 dockerized，一旦测试完成，您可以重新启动 docker 容器，这相当于清理数据库。就我而言，这不是必需的，因为正如我上面提到的，我们已经回滚了测试期间所做的所有更改，这足以满足我们的需求。