Associated with https://bugs.launchpad.net/juju-core/+bug/1454043 the other thing that is filling up the TXN queue is calls $set: {"tools"}.
This may just be a case of "agents are bouncing a lot" and everytime they bounce they set their tools. And in a stable system we wouldn't be bouncing as much.
It does bring up the question if a call to SetToolsVersion is a no-op should we be creating a transaction? I don't think we are worried about concurrent updates, as there should only be 1 agent trying to set its version at any given time.
I suppose if we miss the version then we may not notice that we should be upgrading our version. It is possible to get out of this situation by bouncing an agent (restart jujud-machine-X) at any point.
This gives evidence that it might be really good to do so.
This bug has not been updated in 5 years, so we're marking it Expired. If you believe this is incorrect, please update the status.