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xuzq commented on HDFS-14099: ----------------------------- [~aajisaka] [~jlowe] [~churromorales] have a look? thanks > Unknown frame descriptor when decompressing multiple frames in > ZStandardDecompressor > ------------------------------------------------------------------------------------ > > Key: HDFS-14099 > URL: https://issues.apache.org/jira/browse/HDFS-14099 > Project: Hadoop HDFS > Issue Type: Bug > Environment: Hadoop Version: hadoop-3.0.3 > Java Version: 1.8.0_144 > Reporter: xuzq > Assignee: xuzq > Priority: Major > Attachments: HDFS-14099-trunk-001.patch > > > We need to use the ZSTD compression algorithm in Hadoop. So I write a simple > demo like this for testing. > {code:java} > // code placeholder > while ((size = fsDataInputStream.read(bufferV2)) > 0 ) { > countSize += size; > if (countSize == 65536 * 8) { > if(!isFinished) { > // finish a frame in zstd > cmpOut.finish(); > isFinished = true; > } > fsDataOutputStream.flush(); > fsDataOutputStream.hflush(); > } > if(isFinished) { > LOG.info("Will resetState. N=" + n); > // reset the stream and write again > cmpOut.resetState(); > isFinished = false; > } > cmpOut.write(bufferV2, 0, size); > bufferV2 = new byte[5 * 1024 * 1024]; > n++; > } > {code} > > And I use "*hadoop fs -text*" to read this file and failed. The error as > blow. > {code:java} > Exception in thread "main" java.lang.InternalError: Unknown frame descriptor > at > org.apache.hadoop.io.compress.zstd.ZStandardDecompressor.inflateBytesDirect(Native > Method) > at > org.apache.hadoop.io.compress.zstd.ZStandardDecompressor.decompress(ZStandardDecompressor.java:181) > at > org.apache.hadoop.io.compress.DecompressorStream.decompress(DecompressorStream.java:111) > at > org.apache.hadoop.io.compress.DecompressorStream.read(DecompressorStream.java:105) > at java.io.InputStream.read(InputStream.java:101) > at org.apache.hadoop.io.IOUtils.copyBytes(IOUtils.java:98) > at org.apache.hadoop.io.IOUtils.copyBytes(IOUtils.java:66) > at org.apache.hadoop.io.IOUtils.copyBytes(IOUtils.java:127) > at org.apache.hadoop.fs.shell.Display$Cat.printToStdout(Display.java:101) > at org.apache.hadoop.fs.shell.Display$Cat.processPath(Display.java:96) > at org.apache.hadoop.fs.shell.Command.processPaths(Command.java:331) > at org.apache.hadoop.fs.shell.Command.processPathArgument(Command.java:303) > at org.apache.hadoop.fs.shell.Command.processArgument(Command.java:285) > at org.apache.hadoop.fs.shell.Command.processArguments(Command.java:269) > at > org.apache.hadoop.fs.shell.FsCommand.processRawArguments(FsCommand.java:119) > at org.apache.hadoop.fs.shell.Command.run(Command.java:176) > at org.apache.hadoop.fs.FsShell.run(FsShell.java:328) > at org.apache.hadoop.util.ToolRunner.run(ToolRunner.java:76) > at org.apache.hadoop.util.ToolRunner.run(ToolRunner.java:90) > at org.apache.hadoop.fs.FsShell.main(FsShell.java:391) > {code} > > So I had to look the code, include jni, then found this bug. > *ZSTD_initDStream(stream)* method may by called twice in the same *Frame*. > The first is in *ZStandardDecompressor.c.* > {code:java} > if (size == 0) { > (*env)->SetBooleanField(env, this, ZStandardDecompressor_finished, > JNI_TRUE); > size_t result = dlsym_ZSTD_initDStream(stream); > if (dlsym_ZSTD_isError(result)) { > THROW(env, "java/lang/InternalError", > dlsym_ZSTD_getErrorName(result)); > return (jint) 0; > } > } > {code} > This call here is correct, but *Finished* no longer be set to false, even if > there is some datas (a new frame) in *CompressedBuffer* or *UserBuffer* need > to be decompressed. > The second is in *org.apache.hadoop.io.compress.DecompressorStream* by > *decompressor.reset()*, because *Finished* is always true after decompressed > a *Frame*. > {code:java} > if (decompressor.finished()) { > // First see if there was any leftover buffered input from previous > // stream; if not, attempt to refill buffer. If refill -> EOF, we're > // all done; else reset, fix up input buffer, and get ready for next > // concatenated substream/"member". > int nRemaining = decompressor.getRemaining(); > if (nRemaining == 0) { > int m = getCompressedData(); > if (m == -1) { > // apparently the previous end-of-stream was also end-of-file: > // return success, as if we had never called getCompressedData() > eof = true; > return -1; > } > decompressor.reset(); > decompressor.setInput(buffer, 0, m); > lastBytesSent = m; > } else { > // looks like it's a concatenated stream: reset low-level zlib (or > // other engine) and buffers, then "resend" remaining input data > decompressor.reset(); > int leftoverOffset = lastBytesSent - nRemaining; > assert (leftoverOffset >= 0); > // this recopies userBuf -> direct buffer if using native libraries: > decompressor.setInput(buffer, leftoverOffset, nRemaining); > // NOTE: this is the one place we do NOT want to save the number > // of bytes sent (nRemaining here) into lastBytesSent: since we > // are resending what we've already sent before, offset is nonzero > // in general (only way it could be zero is if it already equals > // nRemaining), which would then screw up the offset calculation > // _next_ time around. IOW, getRemaining() is in terms of the > // original, zero-offset bufferload, so lastBytesSent must be as > // well. Cheesy ASCII art: > // > // <------------ m, lastBytesSent -----------> > // +===============================================+ > // buffer: |1111111111|22222222222222222|333333333333| | > // +===============================================+ > // #1: <-- off -->|<-------- nRemaining ---------> > // #2: <----------- off ----------->|<-- nRem. --> > // #3: (final substream: nRemaining == 0; eof = true) > // > // If lastBytesSent is anything other than m, as shown, then "off" > // will be calculated incorrectly. > } > }{code} -- This message was sent by Atlassian JIRA (v7.6.14#76016) --------------------------------------------------------------------- To unsubscribe, e-mail: hdfs-issues-unsubscr...@hadoop.apache.org For additional commands, e-mail: hdfs-issues-h...@hadoop.apache.org