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https://issues.apache.org/jira/browse/HBASE-12949?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=14337221#comment-14337221
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Jerry He commented on HBASE-12949:
----------------------------------
Hi, [~stack]
Thanks for getting back to this.
BufferUnderflowException and IllegalStateException are both subclass of
RuntimeException. Unchecked, no better, no worse. At least we are using
IllegalStateException currently.
Also, BufferUnderflowException is where we can not even read the length. The
other is where we can read the length, but it is bad.
Here is the case.
Two KVs:
<first-kv-we-can-read-the-length-but-the-length-is-bad><next-kv-we-can-not-even-read-the-length>
With the patch, we fail at the first bad kv.
Without the patch:
1. we can stuck in the first bad kv.
2. BufferUnderflowException in the next kv. This is what happened in the
HFilePrettyPrinter, which uses a ad hoc scanner.
> Scanner can be stuck in infinite loop if the HFile is corrupted
> ---------------------------------------------------------------
>
> Key: HBASE-12949
> URL: https://issues.apache.org/jira/browse/HBASE-12949
> Project: HBase
> Issue Type: Bug
> Affects Versions: 0.94.3, 0.98.10
> Reporter: Jerry He
> Attachments: HBASE-12949-master-v2 (1).patch,
> HBASE-12949-master-v2.patch, HBASE-12949-master-v2.patch,
> HBASE-12949-master.patch
>
>
> We've encountered problem where compaction hangs and never completes.
> After looking into it further, we found that the compaction scanner was stuck
> in a infinite loop. See stack below.
> {noformat}
> org.apache.hadoop.hbase.regionserver.KeyValueHeap.generalizedSeek(KeyValueHeap.java:296)
> org.apache.hadoop.hbase.regionserver.KeyValueHeap.reseek(KeyValueHeap.java:257)
> org.apache.hadoop.hbase.regionserver.StoreScanner.reseek(StoreScanner.java:697)
> org.apache.hadoop.hbase.regionserver.StoreScanner.seekToNextRow(StoreScanner.java:672)
> org.apache.hadoop.hbase.regionserver.StoreScanner.next(StoreScanner.java:529)
> org.apache.hadoop.hbase.regionserver.compactions.Compactor.performCompaction(Compactor.java:223)
> {noformat}
> We identified the hfile that seems to be corrupted. Using HFile tool shows
> the following:
> {noformat}
> [biadmin@hdtest009 bin]$ hbase org.apache.hadoop.hbase.io.hfile.HFile -v -k
> -m -f
> /user/biadmin/CUMMINS_INSITE_V1/7106432d294dd844be15996ccbf2ba84/attributes/f1a7e3113c2c4047ac1fc8fbcb41d8b7
> 15/01/23 11:53:17 INFO Configuration.deprecation: hadoop.native.lib is
> deprecated. Instead, use io.native.lib.available
> 15/01/23 11:53:18 INFO util.ChecksumType: Checksum using
> org.apache.hadoop.util.PureJavaCrc32
> 15/01/23 11:53:18 INFO util.ChecksumType: Checksum can use
> org.apache.hadoop.util.PureJavaCrc32C
> 15/01/23 11:53:18 INFO Configuration.deprecation: fs.default.name is
> deprecated. Instead, use fs.defaultFS
> Scanning ->
> /user/biadmin/CUMMINS_INSITE_V1/7106432d294dd844be15996ccbf2ba84/attributes/f1a7e3113c2c4047ac1fc8fbcb41d8b7
> WARNING, previous row is greater then current row
> filename ->
> /user/biadmin/CUMMINS_INSITE_V1/7106432d294dd844be15996ccbf2ba84/attributes/f1a7e3113c2c4047ac1fc8fbcb41d8b7
> previous ->
> \x00/20110203-094231205-79442793-1410161293068203000\x0Aattributes16794406\x00\x00\x01\x00\x00\x00\x00\x00\x00
> current ->
> Exception in thread "main" java.nio.BufferUnderflowException
> at java.nio.Buffer.nextGetIndex(Buffer.java:489)
> at java.nio.HeapByteBuffer.getInt(HeapByteBuffer.java:347)
> at
> org.apache.hadoop.hbase.io.hfile.HFileReaderV2$ScannerV2.readKeyValueLen(HFileReaderV2.java:856)
> at
> org.apache.hadoop.hbase.io.hfile.HFileReaderV2$ScannerV2.next(HFileReaderV2.java:768)
> at
> org.apache.hadoop.hbase.io.hfile.HFilePrettyPrinter.scanKeysValues(HFilePrettyPrinter.java:362)
> at
> org.apache.hadoop.hbase.io.hfile.HFilePrettyPrinter.processFile(HFilePrettyPrinter.java:262)
> at
> org.apache.hadoop.hbase.io.hfile.HFilePrettyPrinter.run(HFilePrettyPrinter.java:220)
> at org.apache.hadoop.util.ToolRunner.run(ToolRunner.java:70)
> at
> org.apache.hadoop.hbase.io.hfile.HFilePrettyPrinter.main(HFilePrettyPrinter.java:539)
> at org.apache.hadoop.hbase.io.hfile.HFile.main(HFile.java:802)
> {noformat}
> Turning on Java Assert shows the following:
> {noformat}
> Exception in thread "main" java.lang.AssertionError: Key
> 20110203-094231205-79442793-1410161293068203000/attributes:16794406/1099511627776/Minimum/vlen=15/mvcc=0
> followed by a smaller key //0/Minimum/vlen=0/mvcc=0 in cf attributes
> at
> org.apache.hadoop.hbase.regionserver.StoreScanner.checkScanOrder(StoreScanner.java:672)
> {noformat}
> It shows that the hfile seems to be corrupted -- the keys don't seem to be
> right.
> But Scanner is not able to give a meaningful error, but stuck in an infinite
> loop in here:
> {code}
> KeyValueHeap.generalizedSeek()
> while ((scanner = heap.poll()) != null) {
> }
> {code}
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