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https://issues.apache.org/jira/browse/CASSANDRA-15861?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=17142390#comment-17142390
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David Capwell commented on CASSANDRA-15861:
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bq. writeFileToChannelZeroCopy is async, but if I remember correctly about unix
file system: once a file is opened, reader won't be affected by file deletion
or rewrite. So when the synchronized block completes, all component
file-channels are already opened and in-sync with ComponentManifest, even if
they are not flushed from netty outbound buffer to kernel.
Yep, checked and see that each region in netty holds reference to the channel
so you are right, will not be impacted by delete.
bq. The only thing I don't like is redistributing index summary every hour will
explode sstable generation..
That could have negatives for third party tools like backups since they would
look like new sstables; versioning the Statistics.db file would be nice but
adds its own complexity as well.
Looking closer at
org.apache.cassandra.db.streaming.CassandraOutgoingFile#write, why not take
advantage of the fact a FD will be immune to the swap and just create the FD at
the start of the method? This would give you the ability to write the header
and the body without worrying about locking.
> Mutating sstable component may race with entire-sstable-streaming(ZCS)
> causing checksum validation failure
> ----------------------------------------------------------------------------------------------------------
>
> Key: CASSANDRA-15861
> URL: https://issues.apache.org/jira/browse/CASSANDRA-15861
> Project: Cassandra
> Issue Type: Bug
> Components: Consistency/Repair, Consistency/Streaming,
> Local/Compaction
> Reporter: ZhaoYang
> Assignee: ZhaoYang
> Priority: Normal
> Fix For: 4.0-beta
>
>
> Flaky dtest: [test_dead_sync_initiator -
> repair_tests.repair_test.TestRepair|https://ci-cassandra.apache.org/view/all/job/Cassandra-devbranch-dtest/143/testReport/junit/dtest.repair_tests.repair_test/TestRepair/test_dead_sync_initiator/]
> {code:java|title=stacktrace}
> Unexpected error found in node logs (see stdout for full details). Errors:
> [ERROR [Stream-Deserializer-127.0.0.1:7000-570871f3] 2020-06-03 04:05:19,081
> CassandraEntireSSTableStreamReader.java:145 - [Stream
> 6f1c3360-a54f-11ea-a808-2f23710fdc90] Error while reading sstable from stream
> for table = keyspace1.standard1
> org.apache.cassandra.io.sstable.CorruptSSTableException: Corrupted:
> /home/cassandra/cassandra/cassandra-dtest/tmp/dtest-te4ty0r9/test/node3/data0/keyspace1/standard1-5f5ab140a54f11eaa8082f23710fdc90/na-2-big-Statistics.db
> at
> org.apache.cassandra.io.sstable.metadata.MetadataSerializer.maybeValidateChecksum(MetadataSerializer.java:219)
> at
> org.apache.cassandra.io.sstable.metadata.MetadataSerializer.deserialize(MetadataSerializer.java:198)
> at
> org.apache.cassandra.io.sstable.metadata.MetadataSerializer.deserialize(MetadataSerializer.java:129)
> at
> org.apache.cassandra.io.sstable.metadata.MetadataSerializer.mutate(MetadataSerializer.java:226)
> at
> org.apache.cassandra.db.streaming.CassandraEntireSSTableStreamReader.read(CassandraEntireSSTableStreamReader.java:140)
> at
> org.apache.cassandra.db.streaming.CassandraIncomingFile.read(CassandraIncomingFile.java:78)
> at
> org.apache.cassandra.streaming.messages.IncomingStreamMessage$1.deserialize(IncomingStreamMessage.java:49)
> at
> org.apache.cassandra.streaming.messages.IncomingStreamMessage$1.deserialize(IncomingStreamMessage.java:36)
> at
> org.apache.cassandra.streaming.messages.StreamMessage.deserialize(StreamMessage.java:49)
> at
> org.apache.cassandra.streaming.async.StreamingInboundHandler$StreamDeserializingTask.run(StreamingInboundHandler.java:181)
> at
> io.netty.util.concurrent.FastThreadLocalRunnable.run(FastThreadLocalRunnable.java:30)
> at java.lang.Thread.run(Thread.java:748)
> Caused by: java.io.IOException: Checksums do not match for
> /home/cassandra/cassandra/cassandra-dtest/tmp/dtest-te4ty0r9/test/node3/data0/keyspace1/standard1-5f5ab140a54f11eaa8082f23710fdc90/na-2-big-Statistics.db
> {code}
>
> In the above test, it executes "nodetool repair" on node1 and kills node2
> during repair. At the end, node3 reports checksum validation failure on
> sstable transferred from node1.
> {code:java|title=what happened}
> 1. When repair started on node1, it performs anti-compaction which modifies
> sstable's repairAt to 0 and pending repair id to session-id.
> 2. Then node1 creates {{ComponentManifest}} which contains file lengths to be
> transferred to node3.
> 3. Before node1 actually sends the files to node3, node2 is killed and node1
> starts to broadcast repair-failure-message to all participants in
> {{CoordinatorSession#fail}}
> 4. Node1 receives its own repair-failure-message and fails its local repair
> sessions at {{LocalSessions#failSession}} which triggers async background
> compaction.
> 5. Node1's background compaction will mutate sstable's repairAt to 0 and
> pending repair id to null via
> {{PendingRepairManager#getNextRepairFinishedTask}}, as there is no more
> in-progress repair.
> 6. Node1 actually sends the sstable to node3 where the sstable's STATS
> component size is different from the original size recorded in the manifest.
> 7. At the end, node3 reports checksum validation failure when it tries to
> mutate sstable level and "isTransient" attribute in
> {{CassandraEntireSSTableStreamReader#read}}.
> {code}
> Currently, entire-sstable-streaming requires sstable components to be
> immutable, because \{{ComponentManifest}}
> with component sizes are sent before sending actual files. This isn't a
> problem in legacy streaming as STATS file length didn't matter.
>
> Ideally it will be great to make sstable STATS metadata immutable, just like
> other sstable components, so we don't have to worry this special case.
> I can think of 2 ways:
> # Make STATS mutation as a proper compaction to create hard link on the
> compacting sstable components with a new descriptor, except STATS files which
> will be copied entirely. Then mutation will be applied on the new STATS file.
> At the end, old sstable will be released. This ensures all sstable components
> are immutable and shouldn't make these special compaction tasks slower.
> # Change STATS metadata format to use fixed length encoding for repair info
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