[SSHD-1074] Too many SSH_MSG_CHANNEL_WINDOW_ADJUST requests were sent by Server

• Type: Question
• Status: Open
• Priority: Minor
• Resolution: Unresolved
• Labels: user-confirmation-required user-response-required
• Assignee: Unassigned
• Reporter: Sreedhar J
• Created: 02/Sep/20 18:53
• Updated: 02/Apr/21 07:53

Description

During the file transfer to Apache SFTP Server,  I see lot of
SSH_MSG_CHANNEL_WINDOW_ADJUST  requests are sent by Server to client.
 
does it mean not enough buffers to handle?  
 
Here are the log entries
 
2020-09-02 21:54:28,946 [system-thread-1] DEBUG SftpSubsystem - doSendStatus(ServerSessionImpl[admin@/10.84.41.27:60825])[id=1378] SSH_FXP_STATUS (substatus=SSH_FX_OK, lang=, msg=)
2020-09-02 21:54:28,946 [system-thread-1] DEBUG ServerSessionImpl - encode(ServerSessionImpl[admin@/10.84.41.27:60825]) packet #1431 sending command=94[SSH_MSG_CHANNEL_DATA] len=30
2020-09-02 21:54:28,947 [system-thread-1] DEBUG ChannelSession - sendWindowAdjust(ChannelSession[id=0, recipient=0]-ServerSessionImpl[admin@/10.84.41.27:60825]) SSH_MSG_CHANNEL_WINDOW_ADJUST len=1050400
2020-09-02 21:54:28,947 [system-thread-1] DEBUG ServerSessionImpl - encode(ServerSessionImpl[admin@/10.84.41.27:60825]) packet #1432 sending command=93[SSH_MSG_CHANNEL_WINDOW_ADJUST] len=9
2020-09-02 21:54:28,947 [system-thread-1] DEBUG Window - Increase Window[server/local](ChannelSession[id=0, recipient=0]-ServerSessionImpl[admin@/10.84.41.27:60825]) by 1050400 up to 2097152
2020-09-02 21:54:29,022 [NioProcessor-2 ] DEBUG ChannelSession - handleData(ChannelSession[id=0, recipient=0]-ServerSessionImpl[admin@/10.84.41.27:60825]) SSH_MSG_CHANNEL_DATA len=16384
 
21:54:30,471 [system-thread-1] DEBUG SftpSubsystem - doSendStatus(ServerSessionImpl[admin@/10.84.41.27:60825])[id=1410] SSH_FXP_STATUS (substatus=SSH_FX_OK, lang=, msg=)
2020-09-02 21:54:30,471 [system-thread-1] DEBUG ServerSessionImpl - encode(ServerSessionImpl[admin@/10.84.41.27:60825]) packet #1464 sending command=94[SSH_MSG_CHANNEL_DATA] len=30
2020-09-02 21:54:30,471 [system-thread-1] DEBUG ChannelSession - sendWindowAdjust(ChannelSession[id=0, recipient=0]-ServerSessionImpl[admin@/10.84.41.27:60825]) SSH_MSG_CHANNEL_WINDOW_ADJUST len=1050400
2020-09-02 21:54:30,471 [system-thread-1] DEBUG ServerSessionImpl - encode(ServerSessionImpl[admin@/10.84.41.27:60825]) packet #1465 sending command=93[SSH_MSG_CHANNEL_WINDOW_ADJUST] len=9
2020-09-02 21:54:30,471 [system-thread-1] DEBUG Window - Increase Window[server/local](ChannelSession[id=0, recipient=0]-ServerSessionImpl[admin@/10.84.41.27:60825]) by 1050400 up to 2097152
2020-09-02 21:54:30,487 [NioProcessor-2 ] DEBUG ChannelSession - handleData(ChannelSession[id=0, recipient=0]-ServerSessionImpl[admin@/10.84.41.27:60825]) SSH_MSG_CHANNEL_DATA len=16384
2020-09-02 21:54:30,502 [NioProcessor-2 ] DEBUG ChannelSession - handleData(ChannelSession[id=0, recipient=0]-ServerSessionImpl[admin@/10.84.41.27:60825]) SSH_MSG_CHANNEL_DATA len=16384
2020-09-02 21:54:30,502 [system-thread-1] DEBUG SftpSubsystem - process(ServerSessionImpl[admin@/10.84.41.27:60825])[length=32821, type=SSH_FXP_WRITE, id=1411] processing
2020-09-
 

Issue Links

• links to: PuTTY semi-bug flow-control