Hello,
We're experiencing a recurring issue in Cassandra 5.0.5 when performing
token-range read queries on a table using the BTI sstable format. The issue
results in a fatal `AssertionError` during read, which causes read failures
in the client with `ReadFailureException`.
The exception from Cassandra logs looks like this:
```
ERROR [ReadStage-6] 2025-08-27 19:22:49,331 JVMStabilityInspector.java:70 -
Exception in thread Thread[ReadStage-6,5,SharedPool]
java.lang.RuntimeException: java.lang.AssertionError: Caught an error while
trying to process the command: SELECT * FROM keyspace.table WHERE
token(profile_id) > -8987898918496238646 AND token(profile_id) <=
-8718169305572166374 LIMIT 1000 ALLOW FILTERING
at org.apache.cassandra.net.InboundSink.accept(InboundSink.java:108)
at org.apache.cassandra.net.InboundSink.accept(InboundSink.java:45)
at
org.apache.cassandra.net.InboundMessageHandler$ProcessMessage.run(InboundMessageHandler.java:430)
at
org.apache.cassandra.concurrent.ExecutionFailure$1.run(ExecutionFailure.java:133)
at org.apache.cassandra.concurrent.SEPWorker.run(SEPWorker.java:143)
at
io.netty.util.concurrent.FastThreadLocalRunnable.run(FastThreadLocalRunnable.java:30)
at java.base/java.lang.Thread.run(Thread.java:829)
Caused by: java.lang.AssertionError: Caught an error while trying to
process the command: SELECT * FROM keyspace.table WHERE token(profile_id) >
-8987898918496238646 AND token(profile_id) <= -8718169305572166374 LIMIT
1000 ALLOW FILTERING
at
org.apache.cassandra.db.ReadCommandVerbHandler.doVerb(ReadCommandVerbHandler.java:112)
at
org.apache.cassandra.net.InboundSink.lambda$new$0(InboundSink.java:78)
at org.apache.cassandra.net.InboundSink.accept(InboundSink.java:97)
... 6 common frames omitted
Caused by: java.lang.AssertionError: 406005 > 393216
at
org.apache.cassandra.io.util.MmappedRegions$State.floor(MmappedRegions.java:362)
at
org.apache.cassandra.io.util.MmappedRegions.floor(MmappedRegions.java:241)
at
org.apache.cassandra.io.util.MmapRebufferer.rebuffer(MmapRebufferer.java:40)
at org.apache.cassandra.io.tries.Walker.<init>(Walker.java:75)
at
org.apache.cassandra.io.tries.ValueIterator.<init>(ValueIterator.java:96)
at
org.apache.cassandra.io.tries.ValueIterator.<init>(ValueIterator.java:80)
at
org.apache.cassandra.io.sstable.format.bti.PartitionIndex$IndexPosIterator.<init>(PartitionIndex.java:407)
at
org.apache.cassandra.io.sstable.format.bti.PartitionIterator.<init>(PartitionIterator.java:113)
at
org.apache.cassandra.io.sstable.format.bti.PartitionIterator.create(PartitionIterator.java:75)
at
org.apache.cassandra.io.sstable.format.bti.BtiTableReader.coveredKeysIterator(BtiTableReader.java:293)
at
org.apache.cassandra.io.sstable.format.bti.BtiTableScanner$BtiScanningIterator.prepareToIterateRow(BtiTableScanner.java:93)
at
org.apache.cassandra.io.sstable.format.SSTableScanner$BaseKeyScanningIterator.computeNext(SSTableScanner.java:248)
at
org.apache.cassandra.io.sstable.format.SSTableScanner$BaseKeyScanningIterator.computeNext(SSTableScanner.java:228)
at
org.apache.cassandra.utils.AbstractIterator.hasNext(AbstractIterator.java:47)
at
org.apache.cassandra.io.sstable.format.SSTableScanner.hasNext(SSTableScanner.java:190)
at
org.apache.cassandra.db.transform.BasePartitions.hasNext(BasePartitions.java:90)
at
org.apache.cassandra.utils.MergeIterator$Candidate.advance(MergeIterator.java:375)
at
org.apache.cassandra.utils.MergeIterator$ManyToOne.advance(MergeIterator.java:187)
at
org.apache.cassandra.utils.MergeIterator$ManyToOne.computeNext(MergeIterator.java:156)
at
org.apache.cassandra.utils.AbstractIterator.hasNext(AbstractIterator.java:47)
at
org.apache.cassandra.db.partitions.UnfilteredPartitionIterators$4.hasNext(UnfilteredPartitionIterators.java:264)
at
org.apache.cassandra.db.transform.BasePartitions.hasNext(BasePartitions.java:90)
at
org.apache.cassandra.db.partitions.UnfilteredPartitionIterators$Serializer.serialize(UnfilteredPartitionIterators.java:334)
at
org.apache.cassandra.db.ReadResponse$LocalDataResponse.build(ReadResponse.java:201)
at
org.apache.cassandra.db.ReadResponse$LocalDataResponse.<init>(ReadResponse.java:186)
at
org.apache.cassandra.db.ReadResponse.createDataResponse(ReadResponse.java:48)
at
org.apache.cassandra.db.ReadCommand.createResponse(ReadCommand.java:374)
at
org.apache.cassandra.db.ReadCommandVerbHandler.doVerb(ReadCommandVerbHandler.java:93)
... 8 common frames omitted
```
The query itself is a standard paginated scan over token ranges with a
LIMIT. Here's a simplified version of the code performing it:
```kotlin
@Query("select profile_id, token(profile_id) as page_token from
keyspace.table where token(profile_id) > :pageToken limit :limitCount")
fun selectWithToken(
pageToken: Long,
limitCount: Int,
): MappedReactiveResultSet<MigratorEntityToken>
```
This results in read failures like this on the client side:
```
Caused by:
com.datastax.oss.driver.api.core.servererrors.ReadFailureException:
Cassandra failure during read query at consistency LOCAL_QUORUM (2
responses were required but only 0 replica responded, 1 failed)
```
The issue occurs with multiple SSTables, across multiple token ranges, on
different nodes.
All the affected Trie-indexed SSTables, and the error disappears when
switching the sstable format back to Big.
Has anyone else seen similar behavior with BTI sstables in Cassandra 5.0.x?
Is this a known issue or something we should file a Jira ticket for?
Thanks in advance,
Ivan Zalozhnykh
