"Echo port message queue exceeded threshold" (PlanePlotter


New Member

I'm using PlanePlotter as an echo port listener for the PlaneFinder Receiver. Since I've updated to the latest PP version (, the PFR Receiver log is showing below entries:

"Echo port message queue exceeded threshold! Will attempt to disconnect slow listeners"

Then PP is disconnected, later successfully reconnected, and after about 15-30 seconds, above error message re-appears and PP is disconnected, etc.

View the log file:


PP is the only echo port listener. I haven't changed any settings in PP.

PP's change log for
New in version

Manual Mlats are performed peer-to-peer with no server involvement. This makes the procedure the same as the method used by Sector Master Users. As well as reducing the load on the server, this will avoid any synchronisation problems during busy periods.

There are still many new features on my list to add but since it is quite a while since I released a new version, please consider this an interim release.

I've reverted to PP and everything is back to normal again.

The PP developer doesn't understand above log messages. My guess is that PP is slower than previous versions, although the processor load is the same as previous versions (max. 15%).

Any suggestions are appreciated.

Hi Frits,

What is happening is that the buffer we allocate to send to the remote connection is filling faster than it is being received. We are trying to give PP more data than it can process essentially!

If we let this carry on the data PP gets would become old and the PFR would run out of memory.

The message is a protection mechanism as we saw this issue with certain software (not PP) during development.

Looks like something has changed with PlanePlotter now that makes it slower to process the data? I know you are in a really high traffic area too!

The disconnects have disappeared :) after stopping data processing in PP, and then toggling PP's share button. The PP share button can be used while PP is processing, but I suppose it's safer to stop processing first, especially if PP gets a high data rate from the PFR receiver.