[KAFKA-9461] Limit DEBUG statement size when logging failed record value

• Type: Improvement
• Status: Open
• Priority: Minor
• Resolution: Unresolved
• Affects Version/s: 2.4.0
• Component/s: connect
• Assignee: Unassigned
• Reporter: Nicolas Guyomar
• Created: 21/Jan/20 14:15
• Updated: 21/Jan/20 14:26

Description

Hi,

It is possible with the current implementation that we log a full record content at DEBUG level, which can overwhelmed log4j buffer and OOM it : 

That stack trace was due to a 70MB messages refused by a broker 

java.lang.OutOfMemoryError: Java heap space
at java.util.Arrays.copyOf(Arrays.java:3332)
at java.lang.AbstractStringBuilder.ensureCapacityInternal(AbstractStringBuilder.java:124)
at java.lang.AbstractStringBuilder.append(AbstractStringBuilder.java:448)
at java.lang.StringBuffer.append(StringBuffer.java:270)
at org.apache.log4j.helpers.PatternParser$LiteralPatternConverter.format(PatternParser.java:419)
at org.apache.log4j.PatternLayout.format(PatternLayout.java:506)
at org.apache.log4j.WriterAppender.subAppend(WriterAppender.java:310)
at org.apache.log4j.RollingFileAppender.subAppend(RollingFileAppender.java:276)
at org.apache.log4j.WriterAppender.append(WriterAppender.java:162)
at org.apache.log4j.AppenderSkeleton.doAppend(AppenderSkeleton.java:251)
at org.apache.log4j.helpers.AppenderAttachableImpl.appendLoopOnAppenders(AppenderAttachableImpl.java:66)
at org.apache.log4j.Category.callAppenders(Category.java:206)
at org.apache.log4j.Category.forcedLog(Category.java:391)
at org.apache.log4j.Category.log(Category.java:856)
at org.slf4j.impl.Log4jLoggerAdapter.debug(Log4jLoggerAdapter.java:252)
at org.apache.kafka.connect.runtime.WorkerSourceTask$1.onCompletion(WorkerSourceTask.java:330)

  in  https://github.com/apache/kafka/blob/da4337271ef0b72643c0cf47ae51e69f79cf1901/connect/runtime/src/main/java/org/apache/kafka/connect/runtime/WorkerSourceTask.java#L348

Would it make sense to protect Connect directly in the ConnectRecord toString() method and set a configurable limit ? 

 Thank you