dcrwallet Dcrwallet Occasionally Freezing & Missing Votes

Discussion in 'Technical Support' started by David, Sep 13, 2016.

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  1. David

    David Sr. Member

    Jan 22, 2016
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    Hey guys,

    This has been an issue for me for quite some time through multiple versions of Decred software. It's rare and it's difficult to repeat which is why I haven't brought it up here yet. It has caused me to miss several votes in the past, sometimes bringing my missed votes percentage as high as 7%. I am using both Windows 8.1 64 bit on an Intel i7-6700k with a 512gb M.2 SSD and 32GB of RAM, and an Ubuntu Server 14.04.3 LTS 64-bit on Amazon VPS... so I don't believe my hardware is the cause.

    The dcrwallet utility appears to have stopped responding (or stopped outputting to the screen at least) until it is "woken up" using Ctrl+C. In this video, my redundant node picked up the votes so I didn't miss anything... but in another time, both of my PoS nodes froze like this and I saw a whole bunch of "revoked" messages fly by the screen when the wallet was "woken up"... and that was after almost a week of not checking on them.

    Has this happened to anyone else? I believe I saw a known issue on github where the utilities would stop printing to the screen but they would continue to function in the background; however, I don't think that's the issue due to all the missed votes I had. Anyways, here is the screen recording of the issue as it occurred in v0.1.3. I believe it has happened in 0.3.0 as well but I can't confirm that.

    https://vid.me/YfZQ
     
  2. David

    David Sr. Member

    Jan 22, 2016
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    I found the log file showing the most recent issue which occurred running v0.1.3 on my Win 8.1 machine. It shows the wallet working properly on 8-26, then no more output until 09-01 after I "woke it up" with Ctrl+C. The rest of the lines fly by in matter of seconds, throwing dozens of revoked ticket notifications before finally shutting down. Then I upgraded to 0.3.0 on 09-01 and experienced several errors regarding the revoked tickets.

    http://pastebin.com/t6Zzr3Fj

    I know it's for an old version, but I am raising concern to hopefully receive confirmation that you guys know of or have fixed the issue.
     
  3. gravityz3r0

    gravityz3r0 New Member

    Feb 28, 2016
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    To add into your situation, I had the exact same problem with my desktop on Windows 10 i2500k with SSD, all my power settings is configured to make sure that it doesn't enter any sleep state on its own.

    But it keeps happening, dcrd randomly freezing and everything "fly"in once you turn on the screen and start using your computer resulting in missed votes.

    My PC was never in sleep or hibernate mode and my hard disk is set such that it will never sleep/spin down. (Not like it matters anyway).

    However, I tried this and it seems like the problem never happen again.

    1. Press ctrl alt del to bring your task manager.
    2. Locate your dcrd and dcrwallet, right click them and move then to real time priority.
    3. Before turning off your monitor or leaving your computer, maximize both dcrd and dcrwallet Windows and place them side by side. DO NOT minimize them no matter what.


    Let me knows if that help. I suspect there's something behind the SSD mechanism that shut down on its own after a certain period causing the dcrd to stop responding.Just a guess.
     
  4. jolan

    jolan Sr. Member
    Developer

    Dec 7, 2015
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    Well in the video you posted, the dcrwallet window has a white box cursor off the right. This means the window was clicked on at some point which freezes output and probably program execution. You can disable this behavior by right clicking on the title bar -> Properties -> Edit Options -> Uncheck QuickEdit Mode.

    Also you can hit enter instead of ctrl+c to exit the text selection mode.
     
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  5. David

    David Sr. Member

    Jan 22, 2016
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    That would make sense if it was isolated to Windows only. It's happened on both Windows and Linux server.
     
  6. chappjc

    chappjc Full Member
    Developer Pool Operator (PoS)

    #6 chappjc, Sep 14, 2016
    Last edited: Sep 14, 2016
    Are you using tmux and screen on Linux? These programs can do the same thing if they get put then into scrollback mode.

    But what jolan said is right. This happens with cmd.exe all too easy. Use ComEmu perhaps. (Or use a stake pool.)

    I think this part is off topic, but I generally renice dcrd and dcrwallet to -10, or Above Normal on Windows.
     
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  7. David

    David Sr. Member

    Jan 22, 2016
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    Thanks guys. I use screen on Linux but I know I haven't entered scroll back mode prior to it happening. While I want to periodically refresh my dedicated PoS computers with a quick restart every week or so, I do want to get another recording of this happening. It may or may not happen again, especially since I'm on the latest software, but if it does I will get another screen recording.

    I had quick edit mode on for the ease of copying text out of command prompt, but I think I will turn that off due to the risk of it halting processes as jolan said.
     
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  8. Halestorm

    Halestorm Jr. Member

    Jan 22, 2016
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    I run mine using "screen -dmS dcrwallet" and I've never had a problem with scrollback, since there isn't any. If I need to see something that's off screen I just cat/grep the log.
     
  9. chappjc

    chappjc Full Member
    Developer Pool Operator (PoS)

    Well, in screen it's called "copy mode" but it's the same thing. Ctrl+a,[ I think.
     

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