[
https://issues.apache.org/jira/browse/KAFKA-6777?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=16433863#comment-16433863
]
Seweryn Habdank-Wojewodzki edited comment on KAFKA-6777 at 4/11/18 12:58 PM:
-----------------------------------------------------------------------------
One more comment. I see quite often in Kafka that Throwable is converted to
RuntimeException.
This kind of code may lead to situation when OOM will never appear.
I had made simple example:
{code:java}
public class Main {
public static void main ( String[] args ) {
try {
try {
throw new OutOfMemoryError();
// very often in Kafka code:
} catch ( Throwable t ) {
throw ( RuntimeException ) t;
}
// end of very often
} catch ( Exception ignore ) {
}
}
}
{code}
Executed with:
{code:java}
-XX:OnOutOfMemoryError="echo OOM"
{code}
leads to:
{code:java}
Process finished with exit code 0
{code}
I see no *OOM* string, also no _OutOfMemoryError_ is noticed, by any stactrace.
Generally all Errors derived from {{java.lang.Error}} are swallowed, including:
* InternalError,
* OutOfMemoryError,
* StackOverflowError,
* UnknownError,
* ThreadDeath,
* IOError
was (Author: habdank):
One more comment. I see quite often in Kafka that Throwable is converted to
RuntimeException.
This kind of code may lead to situation when OOM will never appear.
I had made simple example:
{code:java}
public class Main {
public static void main ( String[] args ) {
try {
try {
throw new OutOfMemoryError();
// very often in Kafka code:
} catch ( Throwable t ) {
throw ( RuntimeException ) t;
}
// end of very often
} catch ( Exception ignore ) {
}
}
}
{code}
Executed with:
{code:java}
-XX:OnOutOfMemoryError="echo OOM"
{code}
leads to:
{code:java}
Process finished with exit code 0
{code}
I see no *OOM* string, also no _OutOfMemoryError_ is noticed, by any stactrace.
> Wrong reaction on Out Of Memory situation
> -----------------------------------------
>
> Key: KAFKA-6777
> URL: https://issues.apache.org/jira/browse/KAFKA-6777
> Project: Kafka
> Issue Type: Bug
> Components: core
> Affects Versions: 1.0.0
> Reporter: Seweryn Habdank-Wojewodzki
> Priority: Critical
> Attachments: screenshot-1.png
>
>
> Dears,
> We already encountered many times problems related to Out Of Memory situation
> in Kafka Broker and streaming clients.
> The scenario is the following.
> When Kafka Broker (or Streaming Client) is under load and has too less
> memory, there are no errors in server logs. One can see some cryptic entries
> in GC logs, but they are definitely not self-explaining.
> Kafka Broker (and Streaming Clients) works further. Later we see in JMX
> monitoring, that JVM uses more and more time in GC. In our case it grows from
> e.g. 1% to 80%-90% of CPU time is used by GC.
> Next, software collapses into zombie mode – process in not ending. In such a
> case I would expect, that process is crashing (e.g. got SIG SEGV). Even worse
> Kafka treats such a zombie process normal and somewhat sends messages, which
> are in fact getting lost, also the cluster is not excluding broken nodes. The
> question is how to configure Kafka to really terminate the JVM and not remain
> in zombie mode, to give a chance to other nodes to know, that something is
> dead.
> I would expect that in Out Of Memory situation JVM is ended if not graceful
> than at least process is crashed.
--
This message was sent by Atlassian JIRA
(v7.6.3#76005)
