[Twisted-Python] memory leaks

[Glyph Lefkowitz]

> On Dec 6, 2016, at 3:17 AM, bret curtis <psi29a at gmail.com> wrote:
> 
> Isn't this a duplicate of my "memory leak" bug report from about 11 months ago?
> https://twistedmatrix.com/trac/ticket/8164

Yes, thank you for the reference to that.  I've closed the new one and updated the old one.

> Glype's last comment on the ticket was:
> Now, again, I want to be clear that the buffer size here is still a
> bug, and we vastly mis-estimated a reasonable size.

Apparently my opinion hasn't changed, although I didn't remember it ;).

> The end result was that Hawkie indicated that there was a 64K buffer
> of variable length logs. Because they are variable in length means
> they use either almost no memory to potentially causing the OOM to
> come along. What wasn't clear was if you reached the 64K limit, does
> Twisted then just drop the rest of the logs are is the buffer a
> circular one and drops the first entry to accommodate the last entry
> or something else entirely?

It's intended to be a ring buffer, yes, so it should drop the earlier ones.  A PR to shrink the default to something reasonable based on your measurements would be very helpful :).

-glyph