Iterating through client.users to get presences causes 100% CPU

[JMTK]

Please describe the problem you are having in as much detail as possible: I believe this is related to https://github.com/discordjs/discord.js/issues/2809 - When trying to filter/iterate the client.users.cache, the CPU spikes to 100% and becomes unresponsive. Eventually the bot goes offline due to being unable to process anything. My use case was trying to find which percentage of users were offline out of all of the users I had in the cache.

Looking through the User.js class, it should stop on the first match in a guild, however each shard has ~2100 guilds, so I think this loop can add up...

Correct me if I'm wrong on this math, but the worst case scenario could theoretically be (2100 guilds x 252583 users = 533 million iterations) I don't think this would be the common case for each user->guilds->presences match. I currently have ~44 presences per guild, and according to Stackoverflow , the Map.has function is O(1).

Include a reproducible code sample here, if possible:

//need large user count
mybot.users.cache.filter(u => u.presence.status === 'offline')

Further details: Users Count Avg. Presences Per Guild Guild Count

• discord.js version: 12.3.1 (1e63f3756e814d6b1a2a9c17af9c2b28ce37e472)

• Node.js version: 14.12.0

• Operating system: RancherOS: 4.14.138-rancher #1 SMP Sat Aug 10 11:25:46 UTC 2019 x86_64 GNU/Linux

• Priority this issue should have – please be realistic and elaborate if possible: Low Relevant client options:

• partials: none

• gateway intents: "GUILDS", "GUILD_MEMBERS", "GUILD_BANS", "GUILD_VOICE_STATES", "GUILD_PRESENCES", "GUILD_MESSAGES", "DIRECT_MESSAGES"

• other: none

• [X] I have also tested the issue on latest master, commit hash: 1e63f3756e814d6b1a2a9c17af9c2b28ce37e472

[qwright10]

This is completely expected. When you do something in node that requires a lot of "processing power," you CPU usage should and usually will jump up to 100%.

[JMTK]

It's not that I'm surprised that it's 100% CPU, it's that I don't think the current code for accessing a user's presence is scalable in its current state, because it's going to a Guild's presence cache to return it for each user. Before looking at the code, my original assumption was that I would be looping ~252000 times, not 500 million(per shard)

[monbrey]

Presences are Guild-bound. The Discord API does not provide a User.presence directly, hence the getter instead finds one from a Guild.