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https://issues.apache.org/jira/browse/CASSANDRA-10534?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=15003615#comment-15003615
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Stefania commented on CASSANDRA-10534:
--------------------------------------
Thank you for the review and for checking the remaining components. I agree
with your analysis.
These are the components defined in {{SSTableWriter.components()}}:
|| Component || Notes |
| Component.DATA | Sync-ed, SequentialWriter |
| Component.PRIMARY_INDEX | Sync-ed, SequentialWriter |
| Component.STATS | Sync-ed, SequentialWriter |
| Component.SUMMARY | {{SSTableReader.saveSummary()}}, called in finish, not
sync-ed but we write a magic number at the end and we regenerate the summary
when loading it if we don't find this magic number, |
| Component.TOC | Not sync-ed but it's read only by standalone tools |
| Component.DIGEST | Written by {{DataIntegrityMetadata.ChecksumWriter}}, not
sync-ed and not used but intended for users so they can validate uncompressed
data files via sha1sum. In 2.2 this becomes the adler32 checksum that can be
verified with nodetool verify or the standalone verifier.|
| Component.FILTER | Written and sync-ed manually in {{IndexWrit
er.close()}} |
| Component.COMPRESSION_INFO | To be sync-ed by this patch in
{{ompressionMetadata.Writer.close()}} |
| Component.CRC | Sync-ed, SequentialWriter |
bq. I can't quite tell since it looks like it can throw and cause other code
not to execute.
Yes but this was improved in 2.2 with {{LifecycleTransaction}} and in 3.0 even
further with the removal of unfinished left overs via {{LogTransaction}}.
So, IMO, we could have problems with standalone tools and we should probably
sync TOC and DIGEST at some point but it is not critical and probaly best
addressed in another ticket. Shall I open one?
> CompressionInfo not being fsynced on close
> ------------------------------------------
>
> Key: CASSANDRA-10534
> URL: https://issues.apache.org/jira/browse/CASSANDRA-10534
> Project: Cassandra
> Issue Type: Bug
> Reporter: Sharvanath Pathak
> Assignee: Stefania
> Fix For: 2.1.x
>
>
> I was seeing SSTable corruption due to a CompressionInfo.db file of size 0,
> this happened multiple times in our testing with hard node reboots. After
> some investigation it seems like these file is not being fsynced, and that
> can potentially lead to data corruption. I am working with version 2.1.9.
> I checked for fsync calls using strace, and found them happening for all but
> the following components: CompressionInfo, TOC.txt and digest.sha1. All of
> these but the CompressionInfo seem tolerable. Also a quick look through the
> code did not reveal any fsync calls. Moreover, I suspect the commit
> 4e95953f29d89a441dfe06d3f0393ed7dd8586df
> (https://github.com/apache/cassandra/commit/4e95953f29d89a441dfe06d3f0393ed7dd8586df#diff-b7e48a1398e39a936c11d0397d5d1966R344)
> has caused the regression, which removed the line
> {noformat}
> getChannel().force(true);
> {noformat}
> from CompressionMetadata.Writer.close.
> Following is the trace I saw in system.log:
> {noformat}
> INFO [SSTableBatchOpen:1] 2015-09-29 19:24:39,170 SSTableReader.java:478 -
> Opening
> /var/lib/cassandra/data/system/compactions_in_progress-55080ab05d9c388690a4acb25fe1f77b/system-compactions_in_progress-ka-13368
> (79 bytes)
> ERROR [SSTableBatchOpen:1] 2015-09-29 19:24:39,177 FileUtils.java:447 -
> Exiting forcefully due to file system exception on startup, disk failure
> policy "stop"
> org.apache.cassandra.io.sstable.CorruptSSTableException: java.io.EOFException
> at
> org.apache.cassandra.io.compress.CompressionMetadata.<init>(CompressionMetadata.java:131)
> ~[apache-cassandra-2.1.9.jar:2.1.9]
> at
> org.apache.cassandra.io.compress.CompressionMetadata.create(CompressionMetadata.java:85)
> ~[apache-cassandra-2.1.9.jar:2.1.9]
> at
> org.apache.cassandra.io.util.CompressedSegmentedFile$Builder.metadata(CompressedSegmentedFile.java:79)
> ~[apache-cassandra-2.1.9.jar:2.1.9]
> at
> org.apache.cassandra.io.util.CompressedPoolingSegmentedFile$Builder.complete(CompressedPoolingSegmentedFile.java:72)
> ~[apache-cassandra-2.1.9.jar:2.1.9]
> at
> org.apache.cassandra.io.util.SegmentedFile$Builder.complete(SegmentedFile.java:168)
> ~[apache-cassandra-2.1.9.jar:2.1.9]
> at
> org.apache.cassandra.io.sstable.SSTableReader.load(SSTableReader.java:752)
> ~[apache-cassandra-2.1.9.jar:2.1.9]
> at
> org.apache.cassandra.io.sstable.SSTableReader.load(SSTableReader.java:703)
> ~[apache-cassandra-2.1.9.jar:2.1.9]
> at
> org.apache.cassandra.io.sstable.SSTableReader.open(SSTableReader.java:491)
> ~[apache-cassandra-2.1.9.jar:2.1.9]
> at
> org.apache.cassandra.io.sstable.SSTableReader.open(SSTableReader.java:387)
> ~[apache-cassandra-2.1.9.jar:2.1.9]
> at
> org.apache.cassandra.io.sstable.SSTableReader$4.run(SSTableReader.java:534)
> ~[apache-cassandra-2.1.9.jar:2.1.9]
> at
> java.util.concurrent.Executors$RunnableAdapter.call(Executors.java:471)
> [na:1.7.0_80]
> at java.util.concurrent.FutureTask.run(FutureTask.java:262)
> [na:1.7.0_80]
> at
> java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1145)
> [na:1.7.0_80]
> at
> java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:615)
> [na:1.7.0_80]
> at java.lang.Thread.run(Thread.java:745) [na:1.7.0_80]
> Caused by: java.io.EOFException: null
> at
> java.io.DataInputStream.readUnsignedShort(DataInputStream.java:340)
> ~[na:1.7.0_80]
> at java.io.DataInputStream.readUTF(DataInputStream.java:589)
> ~[na:1.7.0_80]
> at java.io.DataInputStream.readUTF(DataInputStream.java:564)
> ~[na:1.7.0_80]
> at
> org.apache.cassandra.io.compress.CompressionMetadata.<init>(CompressionMetadata.java:106)
> ~[apache-cassandra-2.1.9.jar:2.1.9]
> ... 14 common frames omitted
> {noformat}
> Following is the result of ls on the data directory of a corrupted SSTable
> after the hard reboot:
> {noformat}
> $ ls -l
> /var/lib/cassandra/data/system/sstable_activity-5a1ff267ace03f128563cfae6103c65e/
> total 60
> -rw-r--r-- 1 cassandra cassandra 0 Oct 15 09:31
> system-sstable_activity-ka-1-CompressionInfo.db
> -rw-r--r-- 1 cassandra cassandra 9740 Oct 15 09:31
> system-sstable_activity-ka-1-Data.db
> -rw-r--r-- 1 cassandra cassandra 0 Oct 15 09:31
> system-sstable_activity-ka-1-Digest.sha1
> -rw-r--r-- 1 cassandra cassandra 880 Oct 15 09:31
> system-sstable_activity-ka-1-Filter.db
> -rw-r--r-- 1 cassandra cassandra 34000 Oct 15 09:31
> system-sstable_activity-ka-1-Index.db
> -rw-r--r-- 1 cassandra cassandra 7338 Oct 15 09:31
> system-sstable_activity-ka-1-Statistics.db
> -rw-r--r-- 1 cassandra cassandra 0 Oct 15 09:31
> system-sstable_activity-ka-1-TOC.txt
> {noformat}
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