[英]Getting InvalidUsageException in ScalarDB when deleting a record
I am using ScalarDB which provides ACID functionality on Cassandra
.我正在使用 ScalarDB,它在
Cassandra
上提供 ACID 功能。 While deleting a record, I am getting com.scalar.db.exception.transaction.InvalidUsageException: the record to be deleted must be existing and read beforehand
exception.删除记录时,我收到
com.scalar.db.exception.transaction.InvalidUsageException: the record to be deleted must be existing and read beforehand
异常。
I am deleting entries from several tables (thus using Scalar to provide Atomocity).我正在从几个表中删除条目(因此使用 Scalar 来提供 Atomocity)。 I created a
DistributedTransaction
at the start and then started deleting the entries.我在开始时创建了一个
DistributedTransaction
,然后开始删除条目。
def deleteQuestion(questionKey:PracticeQuestionKeys,user:User) = {
logger.trace(s"delete question request ${questionKey}, ${user}")
val transaction = transactionService.start
val questionGetResult = getQuestionFromQuestionID(transaction,questionKey)//
if(questionGetResult.isLeft) throw questionGetResult.left.get
val question = questionGetResult.right.get
deleteQuestionIfUserIsAuthorized(transaction,questionKey, question, user)
deleteQuestionTagFromTagRepository(transaction,question)
deleteQuestionFromProfileAndPortfolio(transaction, question, user.id)
commitTransaction(transaction)
}
All steps before commitTransaction
seem to be ok but `commitTransaction fails with error commitTransaction
之前的所有步骤似乎都没有问题,但是`commitTransaction 失败并出现错误
2020-08-02 13:19:12,883 [WARN] from com.scalar.db.transaction.consensuscommit.CommitHandler in scala-execution-context-global-141 - preparing records failed
com.scalar.db.exception.transaction.InvalidUsageException: the record to be deleted must be existing and read beforehand
at com.scalar.db.transaction.consensuscommit.PrepareMutationComposer.add(PrepareMutationComposer.java:89)
at com.scalar.db.transaction.consensuscommit.PrepareMutationComposer.add(PrepareMutationComposer.java:45)
at com.scalar.db.transaction.consensuscommit.Snapshot.lambda$to$1(Snapshot.java:134)
at java.util.concurrent.ConcurrentHashMap$EntrySetView.forEach(ConcurrentHashMap.java:4795)
at com.scalar.db.transaction.consensuscommit.Snapshot.to(Snapshot.java:130)
at com.scalar.db.transaction.consensuscommit.CommitHandler.prepareRecords(CommitHandler.java:104)
at com.scalar.db.transaction.consensuscommit.CommitHandler.commit(CommitHandler.java:40)
at com.scalar.db.transaction.consensuscommit.ConsensusCommit.commit(ConsensusCommit.java:121)
at services.QuestionsTransactionDatabaseService.commitTransaction(QuestionsTransactionDatabaseService.scala:251)
at services.QuestionsTransactionDatabaseService.deleteQuestion(QuestionsTransactionDatabaseService.scala:388)
at services.QuestionsTransactionService.$anonfun$deleteQuestion$1(QuestionsTransactionService.scala:57)
at scala.runtime.java8.JFunction0$mcV$sp.apply(JFunction0$mcV$sp.java:12)
at scala.concurrent.Future$.$anonfun$apply$1(Future.scala:653)
at scala.util.Success.$anonfun$map$1(Try.scala:251)
at scala.util.Success.map(Try.scala:209)
at scala.concurrent.Future.$anonfun$map$1(Future.scala:287)
at scala.concurrent.impl.Promise.liftedTree1$1(Promise.scala:29)
at scala.concurrent.impl.Promise.$anonfun$transform$1(Promise.scala:29)
at scala.concurrent.impl.CallbackRunnable.run(Promise.scala:60)
at scala.concurrent.impl.ExecutionContextImpl$AdaptedForkJoinTask.exec(ExecutionContextImpl.scala:140)
at java.util.concurrent.ForkJoinTask.doExec(ForkJoinTask.java:289)
at java.util.concurrent.ForkJoinPool$WorkQueue.runTask(ForkJoinPool.java:1056)
at java.util.concurrent.ForkJoinPool.runWorker(ForkJoinPool.java:1692)
at java.util.concurrent.ForkJoinWorkerThread.run(ForkJoinWorkerThread.java:157)
Referring to https://scalardl.readthedocs.io/en/latest/trouble-shooting-guide/ , it seems blind delete is not allowed.参考https://scalardl.readthedocs.io/en/latest/trouble-shooting-guide/ ,好像是不允许盲删的。 But I have tried doing a
get
before delete and have also tried to put conditions like DeleteIfExists
but I am still getting the error.但是我已经尝试在删除之前进行
get
,并且还尝试设置像DeleteIfExists
这样的条件,但我仍然收到错误消息。
def delete(transaction:DistributedTransaction,key:PracticeKeys) = {
logger.trace("Deleting question. Checking if question exists for" + key)
get(transaction,key) //I have tried with and without commenting getting/reading question before deleting
//Perform the operations you want to group in the transaction
val pKey = new Key(new TextValue("id", key.id.toString))
logger.trace(s"created question keys ${pKey}")
logger.trace(s"getting question using ${keyspaceName}, ${tablename}")
val deleteToken:Delete = new Delete(pKey)
.forNamespace(keyspaceName)
.forTable(tablename)
.withCondition(new DeleteIfExists)
transaction.delete(deleteToken)
}
Why do I have to get
a record before deleting it?为什么我必须先
get
记录才能删除它? What is the way to delete straightaway?有什么方法可以直接删除? Am I not using the library correctly?
我没有正确使用图书馆吗?
As it turns out, the problem was in my code.事实证明,问题出在我的代码中。 Firstly, we have to do a
get
before doing a delete
.首先,我们必须在执行
delete
之前执行get
。 I don't know why but that is the rule it seems.我不知道为什么,但这似乎是规则。
So I added a get
in each delete
所以我在每次
delete
中添加了一个get
def delete(transaction:DistributedTransaction,questionKey:QuestionsCreatedByAUserForATagKeys) = {
logger.trace(s"deleting question created for tag with key ${questionKey}")
get(transaction,questionKey) // <-- HERE. I should probably also check if get returned a valid record.
val pQuestionsCreatedKey = new Key(
new TextValue("question_creator", questionKey.creator.creatorId.toString),
new TextValue("tag", questionKey.tag)
)
val cQuestionKey = if(questionKey.creationMonth !=0 && questionKey.creationYear !=0 && questionKey.questionId.isDefined){
new Key(
new BigIntValue("creation_year", questionKey.creationYear),
new BigIntValue("creation_month", questionKey.creationMonth),
new TextValue("question_id", questionKey.questionId.get.toString),
)
} else {
throw CannotDeleteWithoutEntireCompositeKeyException()
}
logger.trace(s"deleting question with keys ${pQuestionsCreatedKey},${cQuestionKey}")
val deleteToken = new Delete(pQuestionsCreatedKey,cQuestionKey)
.forNamespace(keyspaceName)
.forTable(tablename)
.withCondition(new DeleteIfExists)
logger.trace(s"deleting from user profile ${deleteToken}")
transaction.delete(deleteToken)
}
The reason I was getting the exception despite adding get
earlier was due to programming issues (mistakes in assigning variables correctly).尽管较早添加了
get
,但我得到异常的原因是由于编程问题(正确分配变量时的错误)。 Say the delete was for record A
but I hadn't stored A
correctly but had stored it as A1
.假设删除是针对记录
A
但我没有正确存储A
但已将其存储为A1
。 So the get
was actually failing.所以
get
实际上失败了。
In general, I think this error means that the record being deleted doesn't exist.一般来说,我认为这个错误意味着被删除的记录不存在。
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