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https://github.com/xyz327/seata-tcc-timeout-demo
新版 seata 已修复 seata tcc timeout demo https://github.com/seata/seata/issues/3484
https://github.com/xyz327/seata-tcc-timeout-demo
Last synced: about 1 month ago
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新版 seata 已修复 seata tcc timeout demo https://github.com/seata/seata/issues/3484
- Host: GitHub
- URL: https://github.com/xyz327/seata-tcc-timeout-demo
- Owner: xyz327
- Created: 2021-04-30T08:15:36.000Z (over 3 years ago)
- Default Branch: main
- Last Pushed: 2021-04-30T08:16:13.000Z (over 3 years ago)
- Last Synced: 2023-03-03T10:23:26.898Z (almost 2 years ago)
- Language: Java
- Homepage:
- Size: 120 KB
- Stars: 2
- Watchers: 2
- Forks: 1
- Open Issues: 0
-
Metadata Files:
- Readme: README.md
Awesome Lists containing this project
README
# TCC 模式高并发情况下 branch begin/commit/rollback 超时问题
seata server 使用同一个线程池处理所有的请求。线程池 coreSize=50 maxSize=500 queueSize=20000
## seata version 1.4.2
## 复现条件
1. 启动 tc 项目 (已经把 server 的线程池改为单线程(coreSize=1))
2. 启动 rm 项目
3. 启动 tm 项目;
4. 浏览器访问 [http://localhost:8080/global](http://localhost:8080/global)
就会发现长时间不会返回。会在大约 30s 后成功返回`ok`
## 原因分析
### 在 TCC 模式下。
server 在接收到 global commit/rollback 请求后会放入线程池中处理,' 在 global commit/rollback 过程中会调用 branch 的 commit/rollback。
(代码参考 `io.seata.server.coordinator.DefaultCore#doGlobalCommit`)。 branch commit/rollback 是先给 RM 发送 commit/rollback
请求并构造一个 Future 等待RM返回结果。
这个时候就会出现问题。
由于线程池只有一个 global commit/rollback 时已经占用了线程。然后 rm 进行 branch commit/rollback返回结果时就没有线程能过处理这个请求，一直等待. 造成类似死锁问题。最终 Future 等待
30s 超时。 然后在`io.seata.server.coordinator.DefaultCoordinator`中会有一个 retryCommitting 的线程池来做 global commit/rollback 这时候 和
branch commit/rollback 就不会使用同一个线程池了。最终整个分布式事务完成
但是这个等待超时就会严重影响正常的业务逻辑了
***以上是 server 处理线程池只有 1 个的情况。默认 50 个的情况下在高并发时也会出现这个问题***
### 流程图
具体错误堆栈如下
```
14:40:29.431 ERROR --- [ ServerHandlerThread_1_1] i.s.c.e.AbstractExceptionHandler : Catch TransactionException while do RPC, request: xid=192.168.18.115:8091:131405855596744704,extraData=null
==>
io.seata.core.exception.TransactionException: io.seata.core.exception.BranchTransactionException: Send branch commit failed, xid = 192.168.18.115:8091:131405855596744704 branchId = 131405855747739648
at io.seata.server.coordinator.DefaultCore.doGlobalCommit(DefaultCore.java:235)
at io.seata.server.coordinator.DefaultCore.commit(DefaultCore.java:164)
at io.seata.server.coordinator.DefaultCoordinator.doGlobalCommit(DefaultCoordinator.java:167)
at io.seata.server.AbstractTCInboundHandler$2.execute(AbstractTCInboundHandler.java:95)
at io.seata.server.AbstractTCInboundHandler$2.execute(AbstractTCInboundHandler.java:90)
at io.seata.core.exception.AbstractExceptionHandler.exceptionHandleTemplate(AbstractExceptionHandler.java:116)
at io.seata.server.AbstractTCInboundHandler.handle(AbstractTCInboundHandler.java:90)
at io.seata.core.protocol.transaction.GlobalCommitRequest.handle(GlobalCommitRequest.java:34)
at io.seata.server.coordinator.DefaultCoordinator.onRequest(DefaultCoordinator.java:427)
at io.seata.core.rpc.processor.server.ServerOnRequestProcessor.onRequestMessage(ServerOnRequestProcessor.java:116)
at io.seata.core.rpc.processor.server.ServerOnRequestProcessor.process(ServerOnRequestProcessor.java:77)
at io.seata.core.rpc.netty.AbstractNettyRemoting.lambda$processMessage$2(AbstractNettyRemoting.java:278)
at java.base/java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1128)
at java.base/java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:628)
at io.netty.util.concurrent.FastThreadLocalRunnable.run(FastThreadLocalRunnable.java:30)
at java.base/java.lang.Thread.run(Thread.java:834)
Caused by: io.seata.core.exception.BranchTransactionException: Send branch commit failed, xid = 192.168.18.115:8091:131405855596744704 branchId = 131405855747739648
at io.seata.server.coordinator.AbstractCore.branchCommit(AbstractCore.java:161)
at io.seata.server.coordinator.DefaultCore.doGlobalCommit(DefaultCore.java:199)
... 15 common frames omitted
Caused by: java.util.concurrent.TimeoutException: cost 30004 ms
at io.seata.core.protocol.MessageFuture.get(MessageFuture.java:62)
at io.seata.core.rpc.netty.AbstractNettyRemoting.sendSync(AbstractNettyRemoting.java:196)
at io.seata.core.rpc.netty.AbstractNettyRemotingServer.sendSyncRequest(AbstractNettyRemotingServer.java:71)
at io.seata.server.coordinator.AbstractCore.branchCommitSend(AbstractCore.java:168)
at io.seata.server.coordinator.AbstractCore.branchCommit(AbstractCore.java:158)
... 16 common frames omitted
<==
```