IT30450: JAVA OUT OF MEMORY ERROR THROWN BY THE SFTP SERVER ADAPTER

APAR status

• Closed as program error.

Error description

• The SFTP Server Adapter has a very sudden increase in the JVM
  heap size.
  The Noapp JVM goes from approximately 2 GB to 16 GB
  heap size.
  It seems that the issue will take any amount of
  memory available until reaching an OOM.
  The custmer has over 300
  000 file transfer per day and this occurs randomly.
  

Local fix

• RTC #585115
  

Problem summary

• Users Affected:
  All
  
  
  
  Description:
  
  Out of memory with Maverick jars while performing concurrent
  multiple
  login to SFTP server. There is a large GC which is consuming the
  whole system memory.
  
  There were log messages like in heap files:
   "com.maverick.sshd.TransportProtocol" loaded by "<system class
  loader>" occupies 15,085,647,160 (96.42%) bytes. The memory is
  accumulated in one instance of "java.util.LinkedList" loaded by
  "<system class loader>".
  
  
  
  There were couple of issues, whilst the read queue was
  preventing data queuing up past the window space available in
  the server, the write queue could, in theory, grow to
  problematic levels if the server could not send data as fast as
  it could receive it. There was also a socket setting being used
  that may have compounded this, allowing reads to continue when
  we had data queued to write.
  
  
  
  
  Platforms Affected:
  All
  

Problem conclusion

• Resolution Summary
  A code fix is provided.
  
  Maverick jar upgrade to 1.4.70
  
  
  The new version ensures that when there is data to
  write, it is written before it reads. This
  ensures that the write queue is exhausted before further reads.
  
  Added a 100 messages limit to the write queue,
  if this limit is reached threads trying to write data will block
  until there is room in the queue.
  
  
  Delivered In:
  5020603_12
  5020604_3
  6000201
   6000300
  

Temporary fix

Comments

APAR Information

• APAR is sysrouted FROM one or more of the following:

• APAR is sysrouted TO one or more of the following:

Fix information

• Fixed component name

  STR B2B INTEGRA

• Fixed component ID

  5725D0600

Applicable component levels