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https://issues.apache.org/jira/browse/CASSANDRA-15778?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=17108389#comment-17108389
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Alex Petrov commented on CASSANDRA-15778:
-----------------------------------------
After thinking about it for longer time and talking with [~slebresne] and
[~aleksey], I think there're no good solution to this problem. At the moment
{{EmptyType}} assumes that it's fixed-size, therefore doesn't write its size
(only writes bytes). This means that anyone who has already written the value,
won't be able to read it back, and writing a generic scrub tool for that will
be non-trivial since we can have arbitrary bytes there.
>From the alternatives, I think everything we have right now is risky to some
>degree:
* if we inherit {{EmptyType}} from {{BytesType}}, we change semantics of the
empty type, which can have unforeseen consequences
* if we change schema and migrate from {{EmptyType}} to {{BytesType}}, we'll
end up showing the hidden column. To keep it hidden, we'll have to add a flag
to table metadata
* if we just migrate {{EmptyType}} from fixed-size to variable-size
(basically by not overriding {{valueLengthIfFixed}}), it'll work in principle
because of {{BufferCell#hasValue}}, but this also might be risky
So the only reasonable thing to do seems to handle this particular case: people
who still have their 2.1 sstables, and they haven't upgraded, and they're
(somewhat) interested in the data they've written. People who're not interested
in the data they're written receive the same solution, but can just drop the
column.
I suggest we do the following:
* we keep the existing validation that forbids writes into {{EmptyType}}
columns and make {{EmptyType}} write method no-op to be on an even safer side
* we add a way to "unbreak" cql-created thrift-written tables by adding new
{{ALTER TABLE FIX EMPTY TYPE}} (naming is just for example here) statement,
which would _only_ work for cql-created dense tables and nothing else, and
would turn hidden {{EmptyType}} column to {{BytesType}}.
Main reason to ask for human intervention is that we'd like to avoid changes
that can add new problems whie not bein fully satisfactory for the given
problem. This will give anyone with a problem a clear path to a solution
without risking already existing setups.
This also implies that in [CASSANDRA-15811], we'll simply drop {{EmptyType}}
column entirely when doing {{DROP COMPACT STORAGE}}, so no surprising column
without data will show up.
> CorruptSSTableException after a 2.1 SSTable is upgraded to 3.0, failing reads
> -----------------------------------------------------------------------------
>
> Key: CASSANDRA-15778
> URL: https://issues.apache.org/jira/browse/CASSANDRA-15778
> Project: Cassandra
> Issue Type: Bug
> Components: Local/Compaction, Local/SSTable
> Reporter: Sumanth Pasupuleti
> Assignee: Alex Petrov
> Priority: Normal
> Fix For: 3.0.x
>
>
> Below is the exception with stack trace. This issue is consistently
> reproduce-able.
> {code:java}
> ERROR [SharedPool-Worker-1] 2020-05-01 14:57:57,661
> AbstractLocalAwareExecutorService.java:169 - Uncaught exception on thread
> Thread[SharedPool-Worker-1,5,main]ERROR [SharedPool-Worker-1] 2020-05-01
> 14:57:57,661 AbstractLocalAwareExecutorService.java:169 - Uncaught exception
> on thread
> Thread[SharedPool-Worker-1,5,main]org.apache.cassandra.io.sstable.CorruptSSTableException:
> Corrupted:
> /mnt/data/cassandra/data/<ks>/<cf-fda511301fb311e7bd79fd24f2fcfb0d/md-10151-big-Data.db
> at
> org.apache.cassandra.db.columniterator.AbstractSSTableIterator$Reader.hasNext(AbstractSSTableIterator.java:349)
> ~[nf-cassandra-3.0.19.8.jar:3.0.19.8] at
> org.apache.cassandra.db.columniterator.AbstractSSTableIterator.hasNext(AbstractSSTableIterator.java:220)
> ~[nf-cassandra-3.0.19.8.jar:3.0.19.8] at
> org.apache.cassandra.db.columniterator.SSTableIterator.hasNext(SSTableIterator.java:33)
> ~[nf-cassandra-3.0.19.8.jar:3.0.19.8] at
> org.apache.cassandra.db.rows.LazilyInitializedUnfilteredRowIterator.computeNext(LazilyInitializedUnfilteredRowIterator.java:95)
> ~[nf-cassandra-3.0.19.8.jar:3.0.19.8] at
> org.apache.cassandra.db.rows.LazilyInitializedUnfilteredRowIterator.computeNext(LazilyInitializedUnfilteredRowIterator.java:32)
> ~[nf-cassandra-3.0.19.8.jar:3.0.19.8] at
> org.apache.cassandra.utils.AbstractIterator.hasNext(AbstractIterator.java:47)
> ~[nf-cassandra-3.0.19.8.jar:3.0.19.8] at
> org.apache.cassandra.db.transform.BaseRows.hasNext(BaseRows.java:129)
> ~[nf-cassandra-3.0.19.8.jar:3.0.19.8] at
> org.apache.cassandra.db.rows.LazilyInitializedUnfilteredRowIterator.computeNext(LazilyInitializedUnfilteredRowIterator.java:95)
> ~[nf-cassandra-3.0.19.8.jar:3.0.19.8] at
> org.apache.cassandra.db.rows.LazilyInitializedUnfilteredRowIterator.computeNext(LazilyInitializedUnfilteredRowIterator.java:32)
> ~[nf-cassandra-3.0.19.8.jar:3.0.19.8] at
> org.apache.cassandra.utils.AbstractIterator.hasNext(AbstractIterator.java:47)
> ~[nf-cassandra-3.0.19.8.jar:3.0.19.8] at
> org.apache.cassandra.db.transform.BaseRows.hasNext(BaseRows.java:129)
> ~[nf-cassandra-3.0.19.8.jar:3.0.19.8] at
> org.apache.cassandra.db.transform.BaseRows.hasNext(BaseRows.java:129)
> ~[nf-cassandra-3.0.19.8.jar:3.0.19.8] at
> org.apache.cassandra.db.rows.UnfilteredRowIteratorSerializer.serialize(UnfilteredRowIteratorSerializer.java:131)
> ~[nf-cassandra-3.0.19.8.jar:3.0.19.8] at
> org.apache.cassandra.db.rows.UnfilteredRowIteratorSerializer.serialize(UnfilteredRowIteratorSerializer.java:87)
> ~[nf-cassandra-3.0.19.8.jar:3.0.19.8] at
> org.apache.cassandra.db.rows.UnfilteredRowIteratorSerializer.serialize(UnfilteredRowIteratorSerializer.java:77)
> ~[nf-cassandra-3.0.19.8.jar:3.0.19.8] at
> org.apache.cassandra.db.partitions.UnfilteredPartitionIterators$Serializer.serialize(UnfilteredPartitionIterators.java:294)
> ~[nf-cassandra-3.0.19.8.jar:3.0.19.8] at
> org.apache.cassandra.db.ReadResponse$LocalDataResponse.build(ReadResponse.java:187)
> ~[nf-cassandra-3.0.19.8.jar:3.0.19.8] at
> org.apache.cassandra.db.ReadResponse$LocalDataResponse.<init>(ReadResponse.java:180)
> ~[nf-cassandra-3.0.19.8.jar:3.0.19.8] at
> org.apache.cassandra.db.ReadResponse$LocalDataResponse.<init>(ReadResponse.java:176)
> ~[nf-cassandra-3.0.19.8.jar:3.0.19.8] at
> org.apache.cassandra.db.ReadResponse.createDataResponse(ReadResponse.java:76)
> ~[nf-cassandra-3.0.19.8.jar:3.0.19.8] at
> org.apache.cassandra.db.ReadCommand.createResponse(ReadCommand.java:341)
> ~[nf-cassandra-3.0.19.8.jar:3.0.19.8] at
> org.apache.cassandra.db.ReadCommandVerbHandler.doVerb(ReadCommandVerbHandler.java:47)
> ~[nf-cassandra-3.0.19.8.jar:3.0.19.8] at
> org.apache.cassandra.net.MessageDeliveryTask.run(MessageDeliveryTask.java:67)
> ~[nf-cassandra-3.0.19.8.jar:3.0.19.8] at
> java.util.concurrent.Executors$RunnableAdapter.call(Executors.java:511)
> ~[na:1.8.0_231] at
> org.apache.cassandra.concurrent.AbstractLocalAwareExecutorService$FutureTask.run(AbstractLocalAwareExecutorService.java:165)
> ~[nf-cassandra-3.0.19.8.jar:3.0.19.8] at
> org.apache.cassandra.concurrent.AbstractLocalAwareExecutorService$LocalSessionFutureTask.run(AbstractLocalAwareExecutorService.java:137)
> [nf-cassandra-3.0.19.8.jar:3.0.19.8] at
> org.apache.cassandra.concurrent.SEPWorker.run(SEPWorker.java:109)
> [nf-cassandra-3.0.19.8.jar:3.0.19.8] at java.lang.Thread.run(Thread.java:748)
> [na:1.8.0_231]Caused by: java.lang.ArrayIndexOutOfBoundsException: 121 at
> org.apache.cassandra.db.ClusteringPrefix$Deserializer.prepare(ClusteringPrefix.java:425)
> ~[nf-cassandra-3.0.19.8.jar:3.0.19.8] at
> org.apache.cassandra.db.UnfilteredDeserializer$CurrentDeserializer.prepareNext(UnfilteredDeserializer.java:170)
> ~[nf-cassandra-3.0.19.8.jar:3.0.19.8] at
> org.apache.cassandra.db.UnfilteredDeserializer$CurrentDeserializer.hasNext(UnfilteredDeserializer.java:151)
> ~[nf-cassandra-3.0.19.8.jar:3.0.19.8] at
> org.apache.cassandra.db.columniterator.SSTableIterator$ForwardReader.computeNext(SSTableIterator.java:140)
> ~[nf-cassandra-3.0.19.8.jar:3.0.19.8] at
> org.apache.cassandra.db.columniterator.SSTableIterator$ForwardReader.hasNextInternal(SSTableIterator.java:172)
> ~[nf-cassandra-3.0.19.8.jar:3.0.19.8] at
> org.apache.cassandra.db.columniterator.AbstractSSTableIterator$Reader.hasNext(AbstractSSTableIterator.java:336)
> ~[nf-cassandra-3.0.19.8.jar:3.0.19.8] ... 27 common frames omitted
> Caused by: java.lang.ArrayIndexOutOfBoundsException: 121
> at
> org.apache.cassandra.db.ClusteringPrefix$Deserializer.prepare(ClusteringPrefix.java:425)
> ~[nf-cassandra-3.0.19.8.jar:3.0.19.8]
> at
> org.apache.cassandra.db.UnfilteredDeserializer$CurrentDeserializer.prepareNext(UnfilteredDeserializer.java:170)
> ~[nf-cassandra-3.0.19.8.jar:3.0.19.8]
> at
> org.apache.cassandra.db.UnfilteredDeserializer$CurrentDeserializer.hasNext(UnfilteredDeserializer.java:151)
> ~[nf-cassandra-3.0.19.8.jar:3.0.19.8]
> at
> org.apache.cassandra.db.columniterator.SSTableIterator$ForwardReader.computeNext(SSTableIterator.java:140)
> ~[nf-cassandra-3.0.19.8.jar:3.0.19.8]
> at
> org.apache.cassandra.db.columniterator.SSTableIterator$ForwardReader.hasNextInternal(SSTableIterator.java:172)
> ~[nf-cassandra-3.0.19.8.jar:3.0.19.8]
> at
> org.apache.cassandra.db.columniterator.AbstractSSTableIterator$Reader.hasNext(AbstractSSTableIterator.java:336)
> ~[nf-cassandra-3.0.19.8.jar:3.0.19.8] ... 27 common frames omitted
> {code}
> Column family definition
> {code:java}
> CREATE TABLE <keyspace>."<cf>" (
> key text,
> value text,
> PRIMARY KEY (key, value)
> ) WITH COMPACT STORAGE
> AND CLUSTERING ORDER BY (value ASC)
> AND bloom_filter_fp_chance = 0.01
> AND caching = {'keys': 'ALL', 'rows_per_partition': 'NONE'}
> AND comment = ''
> AND compaction = {'class':
> 'org.apache.cassandra.db.compaction.SizeTieredCompactionStrategy',
> 'max_threshold': '32', 'min_threshold': '4'}
> AND compression = {'enabled': 'false'}
> AND crc_check_chance = 1.0
> AND dclocal_read_repair_chance = 0.1
> AND default_time_to_live = 0
> AND gc_grace_seconds = 864000
> AND max_index_interval = 2048
> AND memtable_flush_period_in_ms = 0
> AND min_index_interval = 128
> AND read_repair_chance = 0.0
> AND speculative_retry = '99PERCENTILE';{code}
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