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> -----Original Message----- > From: Allen Reese > Sent: Thursday, February 09, 2012 12:03 PM > To: 'users@tomcat.apache.org' > Cc: Lars Anderson > Subject: Cores with FlushableGzipOutputStream > > We've just upgraded from tomcat 6.0.33 to 6.0.35 and started having the > JVM core on our production boxes. > > I'm trying to determine what the next course of action should be here. > I have an Oracle Support contract, but they don't seem to see this as a > JVM issue, and blame it on a native lib. > > > Thanks. > > Allen Reese > Core Platforms > Yahoo!, Inc. > > Running on linux x86-64, jdk 6u27, 6u29, 6u30, 7u2 > > We run several tests and the output is: > > Jdk | Version | flags > | > 6u30 | 6.0.33 | compression enabled > | works > 6u30 | 6.0.35 | compression enabled > | cores > 6u30 | 6.0.35 | compression disabled > | works > 6u30 | 6.0.35 | Remove changes to FlushableGzipOutputStream [1] > | works > 6u30 | 6.0.35 | -Dsun.zip.disableMemoryMapping=true > | cores > > 7u2 | 6.0.35 | compression enabled > | cores > 7u2 | 6.0.35 | compression disabled > | > 7u2 | 6.0.35 | Remove changes to FlushableGzipOutputStream [1] > | > 7u2 | 6.0.35 | -Dsun.zip.disableMemoryMapping=true > | cores > > https://issues.apache.org/bugzilla/show_bug.cgi?id=52121 > > I filed an SR with Oracle, as this looks like a JVM bug and got the > following response: > > Generic Note > ------------------------ > Hi Allen, > > Thank you for sending the hotspot error logs (hs_err_pid<pid>). Each > one of them has verbiage that indicates the problem is not with Java, > but with native code: > > # Problematic frame: > # C [libzip.so+0x77e3] char+0xa3 > # > # If you would like to submit a bug report, please visit: > # http://java.sun.com/webapps/bugreport/crash.jsp > # The crash happened outside the Java Virtual Machine in native code. > # See problematic frame for where to report the bug. > # > > The case description also noted: > > Rolling back this patch to tomcat increases stability: > http://svn.apache.org/viewvc?view=revision&revision=1197382 > > Again, this points to software other than Java. The Java defect > mentioned, 4813885, was fixed in June of 2009. > ===================== > > Allen Reese > Core Platforms > Yahoo!, Inc. > > [1]: Patch to remove changes to FlushableGZIPOutputStream from 6.0.35. > > --- apache-tomcat-6.0.35- > src/java/org/apache/coyote/http11/filters/FlushableGZIPOutputStream.jav > a 2011-11-28 02:22:45.000000000 -0800 > +++ apache-tomcat-6.0.33- > src/java/org/apache/coyote/http11/filters/FlushableGZIPOutputStream.jav > a 2011-08-16 05:26:14.000000000 -0700 > @@ -35,93 +35,58 @@ > super(os); > } > > + private static final byte[] EMPTYBYTEARRAY = new byte[0]; > + private boolean hasData = false; > + > /** > - * It is used to reserve one byte of real data so that it can be > used when > - * flushing the stream. > + * Here we make sure we have received data, so that the header has > been for > + * sure written to the output stream already. > */ > - private byte[] lastByte = new byte[1]; > - private boolean hasLastByte = false; > - > - @Override > - public void write(byte[] bytes) throws IOException { > - write(bytes, 0, bytes.length); > - } > - > @Override > - public synchronized void write(byte[] bytes, int offset, int > length) > + public synchronized void write(byte[] bytes, int i, int i1) > throws IOException { > - if (length > 0) { > - flushLastByte(); > - if (length > 1) { > - super.write(bytes, offset, length - 1); > - } > - rememberLastByte(bytes[offset + length - 1]); > - } > + super.write(bytes, i, i1); > + hasData = true; > } > > @Override > public synchronized void write(int i) throws IOException { > - flushLastByte(); > - rememberLastByte((byte) i); > + super.write(i); > + hasData = true; > } > > @Override > - public synchronized void finish() throws IOException { > - try { > - flushLastByte(); > - } catch (IOException ignore) { > - // If our write failed, then trailer write in finish() > will fail > - // with IOException as well, but it will leave Deflater in > more > - // consistent state. > - } > - super.finish(); > + public synchronized void write(byte[] bytes) throws IOException { > + super.write(bytes); > + hasData = true; > } > > @Override > - public synchronized void close() throws IOException { > - try { > - flushLastByte(); > - } catch (IOException ignored) { > - // Ignore. As OutputStream#close() says, the contract of > close() > - // is to close the stream. It does not matter much if the > - // stream is not writable any more. > + public synchronized void flush() throws IOException { > + if (!hasData) { > + return; // do not allow the gzip header to be flushed on > its own > } > - super.close(); > - } > > - private void rememberLastByte(byte b) { > - lastByte[0] = b; > - hasLastByte = true; > - } > + // trick the deflater to flush > + /** > + * Now this is tricky: We force the Deflater to flush its data > by > + * switching compression level. As yet, a perplexingly simple > workaround > + * for > + * > http://developer.java.sun.com/developer/bugParade/bugs/4255743.html > + */ > + if (!def.finished()) { > + def.setInput(EMPTYBYTEARRAY, 0, 0); > > - private void flushLastByte() throws IOException { > - if (hasLastByte) { > - // Clear the flag first, because write() may fail > - hasLastByte = false; > - super.write(lastByte, 0, 1); > - } > - } > + def.setLevel(Deflater.NO_COMPRESSION); > + deflate(); > > - @Override > - public synchronized void flush() throws IOException { > - if (hasLastByte) { > - // - do not allow the gzip header to be flushed on its own > - // - do not do anything if there is no data to send > - > - // trick the deflater to flush > - /** > - * Now this is tricky: We force the Deflater to flush its > data by > - * switching compression level. As yet, a perplexingly > simple workaround > - * for > - * > http://developer.java.sun.com/developer/bugParade/bugs/4255743.html > - */ > - if (!def.finished()) { > - def.setLevel(Deflater.NO_COMPRESSION); > - flushLastByte(); > - def.setLevel(Deflater.DEFAULT_COMPRESSION); > - } > + def.setLevel(Deflater.DEFAULT_COMPRESSION); > + deflate(); > + > + out.flush(); > } > - out.flush(); > + > + hasData = false; // no more data to flush > } > > /* --------------------------------------------------------------------- To unsubscribe, e-mail: users-unsubscr...@tomcat.apache.org For additional commands, e-mail: users-h...@tomcat.apache.org
