当并发创建会话时，EngineRef判断当前引擎数量为空时，会不会导致并发创建引擎？ #1952
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Describe the bug当并发创建会话时，EngineRef判断当前引擎数量为空时，会不会导致并发创建引擎？ getServerHost(zkClient, engineSpace).getOrElse { 这段代码在并发上是不是有问题？ Affects Version(s)1.5.0 Kyuubi Server Log OutputNo response Kyuubi Engine Log OutputNo response Kyuubi Server ConfigurationsNo response Kyuubi Engine ConfigurationsNo response Additional contextNo response Are you willing to submit PR?
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Replies: 1 comment 5 replies
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不会。 PS：不确定的问题可以先在Disscutions中创建问题。Issue中不适合做FAQ。 |
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但是，create 中分布式锁方法只能保证创建引擎的进程是唯一的，不能保证重复创建引擎。 由于Zk分布式锁的原因，假设S1 进入了Create 方法， S2 被阻塞； 但是当S1 创建完成引擎，释放分布式锁后， S2 会话会从create方法的分布式锁处唤醒继续执行创建引擎。这就创建了2个引擎 我认为，需要在create方法中增加获取当前引擎的方法 |
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或者getOrCreate 方法设为synchronized |
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@shenbinglife are you looking at the code of master branch ? It seems correct to me org.apache.kyuubi.engine.EngineRef
private def create(
zkClient: CuratorFramework,
extraEngineLog: Option[OperationLog]): (String, Int) = tryWithLock(zkClient) {
// Get the engine address ahead if another process has succeeded
var engineRef = getServerHost(zkClient, engineSpace)
if (engineRef.nonEmpty) return engineRef.get
The code requires the zk lock first, then check if there exists an active engine. |
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very sorry，我的代码是被二次开发出现的问题，删除了关键的代码，master版本非常正确 |
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@shenbinglife thank you for your confirming, welcome to Kyuubi ! |
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不会。
org.apache.kyuubi.engine.EngineRef#create中会获取分布式锁。PS：不确定的问题可以先在Disscutions中创建问题。Issue中不适合做FAQ。