[tor-bugs] #28902 [Core Tor/Nyx]: GETINFO commands with huge outputs slow down interpreter curses interface

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#28902: GETINFO commands with huge outputs slow down interpreter curses interface
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 Reporter:  wagon   |          Owner:  atagar
     Type:  defect  |         Status:  assigned
 Priority:  Medium  |      Component:  Core Tor/Nyx
  Version:          |       Severity:  Normal
 Keywords:  curses  |  Actual Points:
Parent ID:          |         Points:
 Reviewer:          |        Sponsor:
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 If you go to Nyx interpreter, run some commands, then press ESC and arrow
 up, you see that scrolling back in history is very fast and smooth.

 Now do the following:
 1. Run `GETINFO desc/all-recent` command 3 times to get very huge output.
 2. Press ESC and then press HOME to get at the top of scroll buffer.
 3. Press arrow up and arrow down keys many times to scroll up/down.
 4. Press ENTER to return to command interface.
 5. Run some command with small output, e.g. `GETINFO info/names`.
 6. Press ESC and try to scroll few lines up by pressing arrow up many
 times.

 You will see that scrolling is very slow. You need few seconds to scroll
 just few lines up in the buffer.

 Nyx version is
 [[http://ea5faa5po25cf7fb.onion/projects/tor/ticket/28332#comment:7|this
 one]]. The ticket is filed by atagar's
 [[http://ea5faa5po25cf7fb.onion/projects/tor/ticket/28877#comment:3|request]]:
 > I suspect your initial hypothesis about the reason Nyx is freezing is
 inaccurate. Feel free to file a separate ticket with the `nyx --debug`
 output when Nyx freezes so I can see what's up.

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Ticket URL: <https://trac.torproject.org/projects/tor/ticket/28902>
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