I am currently facing an issue where in a transaction fails to commit because of the following exception :
ERROR database.StandardJanusGraph: Could not commit transaction [3] due to storage exception in commit
org.janusgraph.core.JanusGraphException: Could not execute operation due to backend exception
at org.janusgraph.diskstorage.util.BackendOperation.execute(BackendOperation.java:57)
at org.janusgraph.diskstorage.keycolumnvalue.cache.CacheTransaction.persist(CacheTransaction.java:95)
at org.janusgraph.diskstorage.keycolumnvalue.cache.CacheTransaction.flushInternal(CacheTransaction.java:137)
at org.janusgraph.diskstorage.keycolumnvalue.cache.CacheTransaction.commit(CacheTransaction.java:200)
at org.janusgraph.diskstorage.BackendTransaction.commitStorage(BackendTransaction.java:134)
at org.janusgraph.graphdb.database.StandardJanusGraph.commit(StandardJanusGraph.java:737)
at org.janusgraph.graphdb.transaction.StandardJanusGraphTx.commit(StandardJanusGraphTx.java:1374)
at scala.collection.Iterator$class.foreach(Iterator.scala:727)
at scala.collection.AbstractIterator.foreach(Iterator.scala:1157)
at scala.collection.generic.Growable$class.$plus$plus$eq(Growable.scala:48)
at scala.collection.mutable.ArrayBuffer.$plus$plus$eq(ArrayBuffer.scala:103)
at scala.collection.mutable.ArrayBuffer.$plus$plus$eq(ArrayBuffer.scala:47)
at scala.collection.TraversableOnce$class.to(TraversableOnce.scala:273)
at scala.collection.AbstractIterator.to(Iterator.scala:1157)
at scala.collection.TraversableOnce$class.toBuffer(TraversableOnce.scala:265)
at scala.collection.AbstractIterator.toBuffer(Iterator.scala:1157)
at scala.collection.TraversableOnce$class.toArray(TraversableOnce.scala:252)
at scala.collection.AbstractIterator.toArray(Iterator.scala:1157)
at org.apache.spark.rdd.RDD$$anonfun$collect$1$$anonfun$12.apply(RDD.scala:927)
at org.apache.spark.rdd.RDD$$anonfun$collect$1$$anonfun$12.apply(RDD.scala:927)
at org.apache.spark.SparkContext$$anonfun$runJob$5.apply(SparkContext.scala:1858)
at org.apache.spark.SparkContext$$anonfun$runJob$5.apply(SparkContext.scala:1858)
at org.apache.spark.scheduler.ResultTask.runTask(ResultTask.scala:66)
at org.apache.spark.scheduler.Task.run(Task.scala:89)
at org.apache.spark.executor.Executor$TaskRunner.run(Executor.scala:227)
at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1149)
at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:624)
at java.lang.Thread.run(Thread.java:748)
Caused by: org.janusgraph.diskstorage.locking.PermanentLockingException: Expected value mismatch for KeyColumn [k=0x189-115-111-219-124-249-160- 73- 78- 68- 85- 95- 83- 79- 85- 82- 67- 69- 95- 83- 67- 65- 76- 65- 49- 49- 71- 82- 50- 58- 47- 47- 83- 67- 65- 76- 65- 49- 49- 71- 82- 50- 47- 73- 78- 68- 85- 95- 83- 79- 85- 82- 67- 69- 47- 84- 65- 66- 76- 69- 95- 74- 79- 73- 78- 69- 82- 84- 88- 95- 83- 82- 67- 50- 47- 67- 79- 76-177, c=0x 0]: expected=[ 9- 25- 1-176] vs actual=[] (store=graphindex)
at org.janusgraph.diskstorage.locking.consistentkey.ExpectedValueCheckingTransaction.checkSingleExpectedValueUnsafe(ExpectedValueCheckingTransaction.java:289)
at org.janusgraph.diskstorage.locking.consistentkey.ExpectedValueCheckingTransaction.access$000(ExpectedValueCheckingTransaction.java:50)
at org.janusgraph.diskstorage.locking.consistentkey.ExpectedValueCheckingTransaction$1.call(ExpectedValueCheckingTransaction.java:227)
at org.janusgraph.diskstorage.locking.consistentkey.ExpectedValueCheckingTransaction$1.call(ExpectedValueCheckingTransaction.java:224)
at org.janusgraph.diskstorage.util.BackendOperation.executeDirect(BackendOperation.java:69)
at org.janusgraph.diskstorage.locking.consistentkey.ExpectedValueCheckingTransaction.checkSingleExpectedValue(ExpectedValueCheckingTransaction.java:224)
at org.janusgraph.diskstorage.locking.consistentkey.ExpectedValueCheckingTransaction.checkAllExpectedValues(ExpectedValueCheckingTransaction.java:193)
at org.janusgraph.diskstorage.locking.consistentkey.ExpectedValueCheckingTransaction.prepareForMutations(ExpectedValueCheckingTransaction.java:158)
at org.janusgraph.diskstorage.locking.consistentkey.ExpectedValueCheckingStoreManager.mutateMany(ExpectedValueCheckingStoreManager.java:72)
at org.janusgraph.diskstorage.keycolumnvalue.cache.CacheTransaction$1.call(CacheTransaction.java:98)
at org.janusgraph.diskstorage.keycolumnvalue.cache.CacheTransaction$1.call(CacheTransaction.java:95)
at org.janusgraph.diskstorage.util.BackendOperation.executeDirect(BackendOperation.java:69)
at org.janusgraph.diskstorage.util.BackendOperation.execute(BackendOperation.java:55)
Now, what are the possible ways to skip or by pass such transactions, where in its possible that the value read at the start of transaction might be different from that stored in the graph, so resulting in a failure during commit?
I have set storage.transactions property to false. But in the stack trace I could see it is still using the value from the cache.
So, what I basically want is to disable transaction-level cache so that next time when the transaction is replayed it reads the new value instead of the old value in the cache.
I also experimented using the cache.tx-cache-size and cache.tx-dirty-size to 0, however that also didn't help either.
Please let me know if anyone has faced such issues ... happy to take your recommendations.
