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https://issues.apache.org/jira/browse/HIVE-12450?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=15765922#comment-15765922
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Prasanth Jayachandran commented on HIVE-12450:
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It was using Yourkit java profiler.
> OrcFileMergeOperator does not use correct compression buffer size
> -----------------------------------------------------------------
>
> Key: HIVE-12450
> URL: https://issues.apache.org/jira/browse/HIVE-12450
> Project: Hive
> Issue Type: Bug
> Components: ORC
> Affects Versions: 1.2.0, 1.3.0, 1.2.1, 2.0.0
> Reporter: Prasanth Jayachandran
> Assignee: Prasanth Jayachandran
> Priority: Critical
> Fix For: 1.3.0, 2.0.0
>
> Attachments: HIVE-12450.1.patch, HIVE-12450.2.patch,
> HIVE-12450.3.patch, HIVE-12450.4.patch, zlib-hang.png
>
>
> OrcFileMergeOperator checks for compatibility before merging orc files. This
> compatibility check include checking compression buffer size. But the output
> file that is created does not honor the compression buffer size and always
> defaults to 256KB. This will not be a problem when reading the orc file but
> can create unwanted memory pressure because of wasted space within
> compression buffer.
> This issue also can make the merged file unreadable under certain cases. For
> example, if the original compression buffer size is 8KB and if
> hive.exec.orc.default.buffer.size is set to 4KB. The merge file operator will
> use 4KB instead of actual 8KB which can result in hanging of ORC reader (more
> specifically ZlibCodec will wait for more compression buffers).
> {code:title=jstack output for hanging issue}
> "main" prio=5 tid=0x00007fc073000000 nid=0x1703 runnable [0x0000700000218000]
> java.lang.Thread.State: RUNNABLE
> at java.util.zip.Inflater.inflateBytes(Native Method)
> at java.util.zip.Inflater.inflate(Inflater.java:259)
> - locked <0x00000007f5d5fdc8> (a java.util.zip.ZStreamRef)
> at
> org.apache.hadoop.hive.ql.io.orc.ZlibCodec.decompress(ZlibCodec.java:94)
> at
> org.apache.hadoop.hive.ql.io.orc.InStream$CompressedStream.readHeader(InStream.java:238)
> at
> org.apache.hadoop.hive.ql.io.orc.InStream$CompressedStream.read(InStream.java:262)
> at java.io.InputStream.read(InputStream.java:101)
> at
> com.google.protobuf.CodedInputStream.refillBuffer(CodedInputStream.java:737)
> at
> com.google.protobuf.CodedInputStream.isAtEnd(CodedInputStream.java:701)
> at
> com.google.protobuf.CodedInputStream.readTag(CodedInputStream.java:99)
> at
> org.apache.hadoop.hive.ql.io.orc.OrcProto$StripeFooter.<init>(OrcProto.java:10661)
> at
> org.apache.hadoop.hive.ql.io.orc.OrcProto$StripeFooter.<init>(OrcProto.java:10625)
> at
> org.apache.hadoop.hive.ql.io.orc.OrcProto$StripeFooter$1.parsePartialFrom(OrcProto.java:10730)
> at
> org.apache.hadoop.hive.ql.io.orc.OrcProto$StripeFooter$1.parsePartialFrom(OrcProto.java:10725)
> at com.google.protobuf.AbstractParser.parseFrom(AbstractParser.java:89)
> at com.google.protobuf.AbstractParser.parseFrom(AbstractParser.java:95)
> at com.google.protobuf.AbstractParser.parseFrom(AbstractParser.java:49)
> at
> org.apache.hadoop.hive.ql.io.orc.OrcProto$StripeFooter.parseFrom(OrcProto.java:10958)
> at
> org.apache.hadoop.hive.ql.io.orc.MetadataReaderImpl.readStripeFooter(MetadataReaderImpl.java:114)
> at
> org.apache.hadoop.hive.ql.io.orc.RecordReaderImpl.readStripeFooter(RecordReaderImpl.java:240)
> at
> org.apache.hadoop.hive.ql.io.orc.RecordReaderImpl.beginReadStripe(RecordReaderImpl.java:847)
> at
> org.apache.hadoop.hive.ql.io.orc.RecordReaderImpl.readStripe(RecordReaderImpl.java:818)
> at
> org.apache.hadoop.hive.ql.io.orc.RecordReaderImpl.advanceStripe(RecordReaderImpl.java:1033)
> at
> org.apache.hadoop.hive.ql.io.orc.RecordReaderImpl.advanceToNextRow(RecordReaderImpl.java:1068)
> at
> org.apache.hadoop.hive.ql.io.orc.RecordReaderImpl.<init>(RecordReaderImpl.java:217)
> at
> org.apache.hadoop.hive.ql.io.orc.ReaderImpl.rowsOptions(ReaderImpl.java:638)
> at org.apache.hadoop.hive.ql.io.orc.ReaderImpl.rows(ReaderImpl.java:625)
> at
> org.apache.hadoop.hive.ql.io.orc.FileDump.printMetaData(FileDump.java:162)
> at org.apache.hadoop.hive.ql.io.orc.FileDump.main(FileDump.java:110)
> at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
> at
> sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:57)
> at
> sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
> at java.lang.reflect.Method.invoke(Method.java:606)
> at org.apache.hadoop.util.RunJar.run(RunJar.java:221)
> at org.apache.hadoop.util.RunJar.main(RunJar.java:136)
> {code}
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