mojira.dev
MC-6077

Comparators causes block updates while idle

Even when "idle", the comparators update things 2 blocks in front of it and 1 block behind it.
It seems to be doing it every redstone tick(i think) (2 gameticks) which can cause unecessary lag and problems because dispensers can fire on updates etc.

If you flick the lever in the picture the piston will extend because its being updated by the comparator.

Ok, so i actually checked through the code.
Apparently, the comparator is updating itself + the blocks infront/behind when it gets updated. um, derp? ๐Ÿ™‚

Linked issues

Attachments

Comments 44

Confirmed in 13w02b.

Anthony Martin

This behavior is very useful. If it is unintended, it would be nice if this behavior was officially added in some other mechanism.

Because my issue was marked as a duplicate of this issue, despite being different, I'm going to put in a request here as well that it be considered a different bug. My issue is basically the same, except it happens behind the comparator as well. This means comparators are useless for checking dispensers because they cause the dispenser to fire rapidly each time they receive any redstone power. My bug only occurs in the latest snapshot (13w03a) and it actually interferes with gameplay, unlike this bug, which is an annoyance at best.

Henrik Lindstrรถm

I added that it updates blocks behind it aswell to the description ๐Ÿ™‚

"Ok, so i actually checked through the code. Apparently, the comparator is updating itself + the blocks infront/behind when it gets updated."
Wow, that actually explains MC-7771
I mean, if update queue is lost after chunk unload, that is.

34 more comments
Matthew Sitton

As of 13w06a comparators have to face each other to cause block updates.

Yay its back ๐Ÿ˜ƒ

It's not an issue!

Ultimate Omicron

In 13w07a, directly pointing a comparator on normal mode at a self-resetting BUD causes the BUD to blink. Setting the comparator to subtract mode stops the pulsing.

Steve Blanding

Unfortunately, yes, it seems to have been completely fixed now. Why was it changed from 13w07a? I thought that was a reasonable compromise. Now the build I was working on is going to need to be quite a bit larger. ๐Ÿ˜ž

Henrik Lindstrรถm

Jens Bergensten

Confirmed

redstone, redstone-comparator

Snapshot 13w01b, Snapshot 13w02b, Snapshot 13w03a, Snapshot 13w04a, Snapshot 13w07a

Snapshot 13w05a, Snapshot 13w09a

Retrieved