Couchbase 服务器允许并发文档突变，即使设置了 CAS？
Couchbase server allowing concurrent document mutation, even with CAS set?
我有一个对象 SomeObject，它代表一个对象，作为文档存储在 Couchbase 中。 SomeObject 有一个包含 CAS 值的 cas 变量。
我有这样的代码：
/* Get two identical objects from Couchbase, they'll have identical CAS value */
SomeObject someObjectA = getSomeObjectFromCouchbase(sameId);
SomeObject someObjectB = getSomeObjectFromCouchbase(sameId);
/* Make arbitrary modifications to the objects */
someObjectA.getListInObject().add(arbitraryValue1);
someObjectB.getListInObject().add(arbitraryValue2);
/* Convert SomeObject objects to JsonDocument objects, ensuring the CAS value is set */
JsonDocument jsonDocA = JsonDocument.create(someObjectA.getId(), JsonObject.fromJson(mapper.writeValueAsString(someObjectA)), someObjectA.getCas());
JsonDocument jsonDocB = JsonDocument.create(someObjectB.getId(), JsonObject.fromJson(mapper.writeValueAsString(someObjectB)), someObjectB.getCas());
/* Perform upserts on both JsonDocument objects; expectation is the second one should fail with CASMismatchException because the CAS value should have changed after the first upsert */
couchbaseDao.getDatasource().getBucket().upsert(jsonDocA, writeTimeout, TimeUnit.MILLISECONDS);
couchbaseDao.getDatasource().getBucket().upsert(jsonDocB, writeTimeout, TimeUnit.MILLISECONDS);
尽管我预计第二个更新插入应该因 CASMismatchException 而失败，我试图通过将代码包装在 try/catch 块中来捕获它，但它并没有发生。两次 upserts 都成功，并且服务器确实在两次 upsert 之后更改了 CAS 值。就好像它在 upsert 时甚至不检查 CAS 值，只是盲目地接受任何东西然后更新 CAS 值。
最终结果是 Couchbase 文档中的列表仅包含 arbitraryValue2，而缺少 arbitraryValue1，而我希望它具有 arbitraryValue1 而不是 arbitraryValue2（因为第二个 upsert 应该抛出 CASMismatchException）。是我做错了什么，还是服务器出了问题，没有正确处理 CAS？
CAS 只是用在 replace 方法中：
JsonDocument doc = userRepository.getCouchbaseOperations().getCouchbaseBucket().get("1");
JsonDocument doc2 = userRepository.getCouchbaseOperations().getCouchbaseBucket().get("1");
doc.content().put("username", "Michael");
userRepository.getCouchbaseOperations().getCouchbaseBucket().replace(doc);
doc2.content().put("username", "denis");
userRepository.getCouchbaseOperations().getCouchbaseBucket().replace(doc2);
User userResult2 = userRepository.findById("1").get();
System.out.println(userResult2.getUsername());
如果您尝试执行上面的代码，您将遇到以下异常：
aused by: com.couchbase.client.java.error.CASMismatchException: null
at com.couchbase.client.java.bucket.api.Mutate.call(Mutate.java:333) ~[java-client-2.7.11.jar:na]
at com.couchbase.client.java.bucket.api.Mutate.call(Mutate.java:308) ~[java-client-2.7.11.jar:na]
at rx.internal.operators.OnSubscribeMap$MapSubscriber.onNext(OnSubscribeMap.java:69) ~[rxjava-1.3.8.jar:1.3.8]
at rx.observers.Subscribers.onNext(Subscribers.java:235) ~[rxjava-1.3.8.jar:1.3.8]
at rx.internal.operators.OnSubscribeDoOnEach$DoOnEachSubscriber.onNext(OnSubscribeDoOnEach.java:101) ~[rxjava-1.3.8.jar:1.3.8]
at rx.internal.producers.SingleProducer.request(SingleProducer.java:65) ~[rxjava-1.3.8.jar:1.3.8]
at rx.internal.producers.ProducerArbiter.setProducer(ProducerArbiter.java:126) ~[rxjava-1.3.8.jar:1.3.8]
at rx.internal.operators.OnSubscribeTimeoutTimedWithFallback$TimeoutMainSubscriber.setProducer(OnSubscribeTimeoutTimedWithFallback.java:155) ~[rxjava-1.3.8.jar:1.3.8]
at rx.Subscriber.setProducer(Subscriber.java:205) ~[rxjava-1.3.8.jar:1.3.8]
at rx.internal.operators.OnSubscribeMap$MapSubscriber.setProducer(OnSubscribeMap.java:102) ~[rxjava-1.3.8.jar:1.3.8]
at rx.Subscriber.setProducer(Subscriber.java:205) ~[rxjava-1.3.8.jar:1.3.8]
at rx.Subscriber.setProducer(Subscriber.java:205) ~[rxjava-1.3.8.jar:1.3.8]
at rx.subjects.AsyncSubject.onCompleted(AsyncSubject.java:103) ~[rxjava-1.3.8.jar:1.3.8]
at com.couchbase.client.core.endpoint.AbstractGenericHandler.completeResponse(AbstractGenericHandler.java:508) ~[core-io-1.7.11.jar:na]
at com.couchbase.client.core.endpoint.AbstractGenericHandler.access[=11=]0(AbstractGenericHandler.java:86) ~[core-io-1.7.11.jar:na]
at com.couchbase.client.core.endpoint.AbstractGenericHandler.call(AbstractGenericHandler.java:526) ~[core-io-1.7.11.jar:na]
at rx.internal.schedulers.ScheduledAction.run(ScheduledAction.java:55) ~[rxjava-1.3.8.jar:1.3.8]
at java.base/java.util.concurrent.Executors$RunnableAdapter.call(Executors.java:515) ~[na:na]
at java.base/java.util.concurrent.FutureTask.run(FutureTask.java:264) ~[na:na]
at java.base/java.util.concurrent.ScheduledThreadPoolExecutor$ScheduledFutureTask.run(ScheduledThreadPoolExecutor.java:304) ~[na:na]
at java.base/java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1128) ~[na:na]
at java.base/java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:628) ~[na:na]
at java.base/java.lang.Thread.run(Thread.java:835) ~[na:na]
Caused by: rx.exceptions.OnErrorThrowable$OnNextValue: OnError while emitting onNext value: com.couchbase.client.core.message.kv.ReplaceResponse.class
对于这里的 GO 用户，我正在使用 upsertSpec 和 CAS 来找出文档中的任何并行突变。它对我来说似乎工作得很好。虽然不确定 java SDK，但理想情况下，无论语言如何，行为都应该相同。
我有一个对象 SomeObject，它代表一个对象，作为文档存储在 Couchbase 中。 SomeObject 有一个包含 CAS 值的 cas 变量。
我有这样的代码：
/* Get two identical objects from Couchbase, they'll have identical CAS value */
SomeObject someObjectA = getSomeObjectFromCouchbase(sameId);
SomeObject someObjectB = getSomeObjectFromCouchbase(sameId);
/* Make arbitrary modifications to the objects */
someObjectA.getListInObject().add(arbitraryValue1);
someObjectB.getListInObject().add(arbitraryValue2);
/* Convert SomeObject objects to JsonDocument objects, ensuring the CAS value is set */
JsonDocument jsonDocA = JsonDocument.create(someObjectA.getId(), JsonObject.fromJson(mapper.writeValueAsString(someObjectA)), someObjectA.getCas());
JsonDocument jsonDocB = JsonDocument.create(someObjectB.getId(), JsonObject.fromJson(mapper.writeValueAsString(someObjectB)), someObjectB.getCas());
/* Perform upserts on both JsonDocument objects; expectation is the second one should fail with CASMismatchException because the CAS value should have changed after the first upsert */
couchbaseDao.getDatasource().getBucket().upsert(jsonDocA, writeTimeout, TimeUnit.MILLISECONDS);
couchbaseDao.getDatasource().getBucket().upsert(jsonDocB, writeTimeout, TimeUnit.MILLISECONDS);
尽管我预计第二个更新插入应该因 CASMismatchException 而失败，我试图通过将代码包装在 try/catch 块中来捕获它，但它并没有发生。两次 upserts 都成功，并且服务器确实在两次 upsert 之后更改了 CAS 值。就好像它在 upsert 时甚至不检查 CAS 值，只是盲目地接受任何东西然后更新 CAS 值。
最终结果是 Couchbase 文档中的列表仅包含 arbitraryValue2，而缺少 arbitraryValue1，而我希望它具有 arbitraryValue1 而不是 arbitraryValue2（因为第二个 upsert 应该抛出 CASMismatchException）。是我做错了什么，还是服务器出了问题，没有正确处理 CAS？
CAS 只是用在 replace 方法中：
JsonDocument doc = userRepository.getCouchbaseOperations().getCouchbaseBucket().get("1");
JsonDocument doc2 = userRepository.getCouchbaseOperations().getCouchbaseBucket().get("1");
doc.content().put("username", "Michael");
userRepository.getCouchbaseOperations().getCouchbaseBucket().replace(doc);
doc2.content().put("username", "denis");
userRepository.getCouchbaseOperations().getCouchbaseBucket().replace(doc2);
User userResult2 = userRepository.findById("1").get();
System.out.println(userResult2.getUsername());
如果您尝试执行上面的代码，您将遇到以下异常：
aused by: com.couchbase.client.java.error.CASMismatchException: null
at com.couchbase.client.java.bucket.api.Mutate.call(Mutate.java:333) ~[java-client-2.7.11.jar:na]
at com.couchbase.client.java.bucket.api.Mutate.call(Mutate.java:308) ~[java-client-2.7.11.jar:na]
at rx.internal.operators.OnSubscribeMap$MapSubscriber.onNext(OnSubscribeMap.java:69) ~[rxjava-1.3.8.jar:1.3.8]
at rx.observers.Subscribers.onNext(Subscribers.java:235) ~[rxjava-1.3.8.jar:1.3.8]
at rx.internal.operators.OnSubscribeDoOnEach$DoOnEachSubscriber.onNext(OnSubscribeDoOnEach.java:101) ~[rxjava-1.3.8.jar:1.3.8]
at rx.internal.producers.SingleProducer.request(SingleProducer.java:65) ~[rxjava-1.3.8.jar:1.3.8]
at rx.internal.producers.ProducerArbiter.setProducer(ProducerArbiter.java:126) ~[rxjava-1.3.8.jar:1.3.8]
at rx.internal.operators.OnSubscribeTimeoutTimedWithFallback$TimeoutMainSubscriber.setProducer(OnSubscribeTimeoutTimedWithFallback.java:155) ~[rxjava-1.3.8.jar:1.3.8]
at rx.Subscriber.setProducer(Subscriber.java:205) ~[rxjava-1.3.8.jar:1.3.8]
at rx.internal.operators.OnSubscribeMap$MapSubscriber.setProducer(OnSubscribeMap.java:102) ~[rxjava-1.3.8.jar:1.3.8]
at rx.Subscriber.setProducer(Subscriber.java:205) ~[rxjava-1.3.8.jar:1.3.8]
at rx.Subscriber.setProducer(Subscriber.java:205) ~[rxjava-1.3.8.jar:1.3.8]
at rx.subjects.AsyncSubject.onCompleted(AsyncSubject.java:103) ~[rxjava-1.3.8.jar:1.3.8]
at com.couchbase.client.core.endpoint.AbstractGenericHandler.completeResponse(AbstractGenericHandler.java:508) ~[core-io-1.7.11.jar:na]
at com.couchbase.client.core.endpoint.AbstractGenericHandler.access[=11=]0(AbstractGenericHandler.java:86) ~[core-io-1.7.11.jar:na]
at com.couchbase.client.core.endpoint.AbstractGenericHandler.call(AbstractGenericHandler.java:526) ~[core-io-1.7.11.jar:na]
at rx.internal.schedulers.ScheduledAction.run(ScheduledAction.java:55) ~[rxjava-1.3.8.jar:1.3.8]
at java.base/java.util.concurrent.Executors$RunnableAdapter.call(Executors.java:515) ~[na:na]
at java.base/java.util.concurrent.FutureTask.run(FutureTask.java:264) ~[na:na]
at java.base/java.util.concurrent.ScheduledThreadPoolExecutor$ScheduledFutureTask.run(ScheduledThreadPoolExecutor.java:304) ~[na:na]
at java.base/java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1128) ~[na:na]
at java.base/java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:628) ~[na:na]
at java.base/java.lang.Thread.run(Thread.java:835) ~[na:na]
Caused by: rx.exceptions.OnErrorThrowable$OnNextValue: OnError while emitting onNext value: com.couchbase.client.core.message.kv.ReplaceResponse.class
对于这里的 GO 用户，我正在使用 upsertSpec 和 CAS 来找出文档中的任何并行突变。它对我来说似乎工作得很好。虽然不确定 java SDK，但理想情况下，无论语言如何，行为都应该相同。