Skript: Local variables making RAM going to 0 (dev37c)

[YellowZaki]

Yesterday I updated from a old version of skript to dev37c.
Today I noticed huge lag spikes. Then I realised the RAM was reaching 0. When I start the server, the RAM starts decreasing slowly until 0mb when lag spikes occur.

I made a RAM Dump and I found that +90% of the RAM was because of skript, specifically it was about local variables.

[TheBentoBox]

This doesn't really mean anything without us seeing how you're handling local variables in your scripts. I've never heard of anyone else having this issue so for all we know you're generating a ton of local variables with laggy, high frequency events.

[YellowZaki]

I have been using Skript 2.2-dev29 for months and I hadn't have any problems. The ram issue comes from yesterday and the only changes I made yesterday on the server were updating Skript and SKQuery, I'll try downgrading SkQuery to see if something changes.

[bensku]

Some old Skript versions do have memory leaks, but I didn't think dev37c was one of those. If it is, I wonder how most users have not noticed anything.

If this happens without addons, I could take a look at heap dump.

[YellowZaki]

I attach some screenshots of the memory dump, if it helps.

[bensku]

That bug should not exist on dev37b, are you sure it is that version? Might also be caused by addons, please try running without them and see if memory is still leaking.

[YellowZaki]

The same thing happens without addons. But I have noticed something.

On older skript versions, a large portion of RAM is occupied by local variables too. But when RAM goes down to ~50mb, it goes up to the max value again, instead of dropping to 0mb and lagging the server (dev37).

[bensku]

Could you try to pinpoint which script, if any, causes this to happen, and send it here? Sadly, I have no idea how to reproduce this issue.

[Feerko]

Hello,

@bensku i have a similar problem and i'm also using dev37c

the server has been on for 8 hours. variables.csv weighs 7mb while there are 150 people on the server. the server now uses 15gb of RAM.

on join:
  send request to "xxxxx" # ~50 variables, json like this: https://pastebin.com/raw/inFdiGg8
  map json last response's body to {player::%player%::*}

on quit:
  delete {player::%player%::*}

[Feerko]

Hmm, I have variables like this:

{player::%player%::profile::exp}
{player::%player%::stats::kills}
...

maybe delete {player::%player%::*}
doesn't remove {player::%player%::*::*} and that's the reason.

[Feerko]

i think i found it

function var():
  loop 100 times:
    set {test::%loop-num-1%} to loop-num-1
    loop 100 times:
      set {test::%loop-num-1%::%loop-num-2%} to random number between 11111111 and 99999999

command /test:
  trigger:
    loop 100 times:
      var()
      delete {test::*}
      wait 1 tick

[bensku]

@Feerko You're correct that nested lists are not removed. That is because Skript doesn't really support nested lists... This is not a bug, although with next variable system supporting nested lists would be nice.

OP is having a problem with local variables causing a memory leak. I've yet to see any anything I could use to reproduce this.

[Feerko]

@bensku What can I do with this? Within 2 hours my server consumes 10GB of RAM.

[bensku]

@Feerko Iterate through lists before deleting and delete your "sublists" too.

In the other news, I identified a problem with periodical events causing local variables to slowly leak. It may fix this issue.

[TheBentoBox]

Iterate through lists before deleting and delete your "sublists" too.

Last I recalled, iterating over a list which contains sub-lists does not iterate over the indices representing those sub-lists, so this wouldn't work. Maybe my info is wrong or outdated, though.

[Feerko]

Tried, doesn't work. RAM grows and grows. When the server reaches Xmx, the CPU usage drastically increases, tps drops a lot and crash server.

Removing variables does not free RAM. I've tried everything.

[bensku]

@TheBentoBox You can add non-list keys in addition to list keys, and then iterate over them.

Not tested, but something like

function var():
  loop 100 times:
    set {test::%loop-num-1%} to loop-num-1
    loop 100 times:
      set {test::%loop-num-1%} to true
      set {test::%loop-num-1%::%loop-num-2%} to random number between 11111111 and 99999999

command /test:
  trigger:
    loop 100 times:
      var()
      loop {test::*}:
        delete {test::%loop-index%::*}
      delete {test::*}
      wait 1 tick

[bensku]

New release is out. Could someone check if this still occurs?

[bensku]

Closing in a few days unless someone still has this issue.