What is rollback and how does it work?

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Wuzzy
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What is rollback and how does it work?

by Wuzzy » Post

So Minetest has this rollback feature since a while now. You can find it in the server commands.
/help rollback and /help rollback_check.

But to be honest, I haven't figured out what this rollback thing is, what it does and how it is supposed to be used. The chat command help is not very detailed.

What is rollback and how does it work?
What exactly is “rolled back”?´
And what is this weird actor argument for?

hajo
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Re: What is rollback and how does it work?

by hajo » Post

Wuzzy wrote:What is rollback and how does it work?
* Wikipedia - "returns the database to some previous state .. usually implemented with a transaction log"
* https://wiki.minetest.net/Server_commands#Rollback
* http://dev.minetest.net/Global_Minetest_object#Rollback

HalvorRaknes
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Re: What is rollback and how does it work?

by HalvorRaknes » Post

I also wonder what the "actor" argument is (as versus the "user" argument).

Also I cannot figure out what I should enter for myself since I'm playing in single-user mode.

Mineminer
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Re: What is rollback and how does it work?

by Mineminer » Post

Wuzzy wrote:
Thu Jan 25, 2018 01:32
So Minetest has this rollback feature since a while now. You can find it in the server commands.
/help rollback and /help rollback_check.

But to be honest, I haven't figured out what this rollback thing is, what it does and how it is supposed to be used. The chat command help is not very detailed.

What is rollback and how does it work?
What exactly is “rolled back”?´
And what is this weird actor argument for?
It also apparently at the expense of disk activity. But I am confused if it mainly IO (Input and Output) OR if it IOPS (Inputs and Outputs Per Second).

So I just Rdiff-Backup a centralized place from my machine frequently throughout the day on the daily to a remote AND do a daily restart which also zips everything to a local (but seperate) NFS encrypted share.

So "if the gater hits the fans" we are prepared either way.

LordPhyre
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Re: What is rollback and how does it work?

by LordPhyre » Post

HalvorRaknes wrote:
Wed Nov 24, 2021 15:14
I also wonder what the "actor" argument is (as versus the "user" argument).

Also I cannot figure out what I should enter for myself since I'm playing in single-user mode.
All singleplayer accounts have the name "singleplayer". So if you have rollback enabled on that world, and you want to rollback your actions on that world (placing, breaking, taking/putting items in chests, giving privs?) then use "singleplayer" as the target.
Wuzzy wrote:
Thu Jan 25, 2018 01:32
But to be honest, I haven't figured out what this rollback thing is, what it does and how it is supposed to be used. The chat command help is not very detailed.

What is rollback and how does it work?
What exactly is “rolled back”?´
And what is this weird actor argument for?
Rollback is just a command that works as a permanent wayback machine for any player related activities done on your world/server.
When inputting a name for /rollback, all actions within the timespan specified will be permanently undone. As of now, I don't think there's a way to undo rollback.
This includes any physical manipulation of the world, movement of items, and possibly undoing certain commands (like /grant or /revoke, though I haven't fully tested this.)
Worldedit doesn't count, because for some reason maybe worldedit actions are labeled as server actions, not player actions. I don't know really.

Rollback_check is only to view who did rollback-able actions within a specified radius.
It gives you a log of blocks placed/destroyed, based on how long back you want, where/which blocks to check for, and also how many lines of data you would like to see, (I think the limit for that is 100 lines.)

It's a very simple concept, really. But I don't know how it works. Not that I really care, but it would be interesting to know.

As for the weird "actor" argument, I have no clue what you're talking about.

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