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Posted to log4j-dev@logging.apache.org by "Gary Gregory (JIRA)" <ji...@apache.org> on 2015/12/22 20:45:46 UTC
[jira] [Updated] (LOG4J2-1230) Concatenated SYSLOG Messages
[ https://issues.apache.org/jira/browse/LOG4J2-1230?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel ]
Gary Gregory updated LOG4J2-1230:
---------------------------------
Description:
Under heavy traffic load several SYSLOG messages can be concatenated, which is not correct.
The problem is, several threads in AbstractOutputStreamAppender can reach in the next code write() before one thread reaches flush() (the readLock.lock() is not lock at all)
{code:java}
@Override
public void append(final LogEvent event) {
readLock.lock();
try {
final byte[] bytes = getLayout().toByteArray(event);
if (bytes.length > 0) {
manager.write(bytes);
if (this.immediateFlush || event.isEndOfBatch()) {
manager.flush();
}
}
} catch (final AppenderLoggingException ex) {
error("Unable to write to stream " + manager.getName() + " for appender " + getName());
throw ex;
} finally {
readLock.unlock();
}
}
{code}
In DatagramOutputStream all messages are cumulated in instance variable
private byte[] data;
Synchronized methods don't help and in this case the synchronization in DatagramOutputStream is useless, as the correct synchronization should be provided in AbstractOutputStreamAppender.
was:
Under heavy traffic load several SYSLOG messages can be concatenated, which is not correct.
The problem is, several threads in AbstractOutputStreamAppender can reach in the next code write() before one thread reaches flush() (the readLock.lock() is not lock at all)
@Override
public void append(final LogEvent event) {
readLock.lock();
try {
final byte[] bytes = getLayout().toByteArray(event);
if (bytes.length > 0) {
manager.write(bytes);
if (this.immediateFlush || event.isEndOfBatch()) {
manager.flush();
}
}
} catch (final AppenderLoggingException ex) {
error("Unable to write to stream " + manager.getName() + " for appender " + getName());
throw ex;
} finally {
readLock.unlock();
}
}
In DatagramOutputStream all messages are cumulated in instance variable
private byte[] data;
Synchronized methods don't help and in this case the synchronization in DatagramOutputStream is useless, as the correct synchronization should be provided in AbstractOutputStreamAppender.
> Concatenated SYSLOG Messages
> ----------------------------
>
> Key: LOG4J2-1230
> URL: https://issues.apache.org/jira/browse/LOG4J2-1230
> Project: Log4j 2
> Issue Type: Bug
> Components: Core
> Affects Versions: 2.5
> Environment: Linux, Java7, WebLogic 12
> Reporter: Vladimir Hudec
> Original Estimate: 8h
> Remaining Estimate: 8h
>
> Under heavy traffic load several SYSLOG messages can be concatenated, which is not correct.
> The problem is, several threads in AbstractOutputStreamAppender can reach in the next code write() before one thread reaches flush() (the readLock.lock() is not lock at all)
> {code:java}
> @Override
> public void append(final LogEvent event) {
> readLock.lock();
> try {
> final byte[] bytes = getLayout().toByteArray(event);
> if (bytes.length > 0) {
> manager.write(bytes);
> if (this.immediateFlush || event.isEndOfBatch()) {
> manager.flush();
> }
> }
> } catch (final AppenderLoggingException ex) {
> error("Unable to write to stream " + manager.getName() + " for appender " + getName());
> throw ex;
> } finally {
> readLock.unlock();
> }
> }
> {code}
> In DatagramOutputStream all messages are cumulated in instance variable
> private byte[] data;
> Synchronized methods don't help and in this case the synchronization in DatagramOutputStream is useless, as the correct synchronization should be provided in AbstractOutputStreamAppender.
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