MaxRegistrationsPerBlockSet

Event Re-added v101 → v219, v233 → v265, v273 → v277, v290 → current #14

Emitted when maximum registrations per block is changed.

Useful for: minersvalidatorssubnet ownersanalyticsdevelopers

The Big Picture

Even if many people want to register in the same block, there's a cap on how many can succeed. This prevents registration races from overwhelming the network. If 100 people try to register but the max is 3, only 3 succeed (usually first-in wins). This event changes that cap.

Why This Matters

On hot subnets, registration is competitive. If the per-block max is low, you're competing for limited slots each block. Higher max means less per-block competition. Understanding this helps you time registration attempts and set realistic expectations.

Example Scenario

Subnet 1 is extremely popular with many registration attempts. To prevent block congestion, the max is set to 2 per block. MaxRegistrationsPerBlockSet fires. Even with 50 pending registrations, only 2 succeed per block. You might need to retry multiple times or wait for less busy periods.

Common Questions

What happens to registrations that exceed the limit?: They fail and must retry in the next block. You lose the transaction fee but not your burn (burn only happens on success). Keep trying until you get a slot.
How do I increase my chances of getting through?: Submit early in blocks (if possible), set higher priority fees if supported, or try during off-peak times. Some luck is involved.
Does this limit apply to PoW and burn separately?: Usually it's a combined limit for the subnet. Check your subnet's specific implementation for whether there are separate limits per registration type.

Use Cases

Track registration throughput limits
Plan registration timing during high demand
Monitor subnet capacity management
Build registration queue management tools

How to Use This Event

→ Monitor throughput limits on competitive subnets
→ Build registration timing optimization
→ Track registration capacity policies

From Chain Metadata

we set max registrations per block.

Triggers

Preconditions

Caller has admin/sudo privileges

Effects

Postconditions

MaxRegistrationsPerBlock updated

Side Effects

Limits registration throughput per block

Event Data

#	Name	Type	Description
0	arg0	u16	Event field #0 (u16)
1	arg1	u16	Event field #1 (u16)

Code Examples

import { ApiPromise, WsProvider } from "@polkadot/api";
import { stringCamelCase } from "@polkadot/util";

const provider = new WsProvider("wss://entrypoint-finney.opentensor.ai:443");
const api = await ApiPromise.create({ provider });

// Subscribe to MaxRegistrationsPerBlockSet events
api.query.system.events((events) => {
  events
    .filter(({ event }) =>
      event.section === stringCamelCase("SubtensorModule") &&
      event.method === "MaxRegistrationsPerBlockSet"
    )
    .forEach(({ event }) => {
      console.log("MaxRegistrationsPerBlockSet:", event.data.toHuman());
    });
});

Version History

Version:

v101 block 1 2 args

v233 block 4,920,350 2 args

v273 block 5,659,032 2 args

v290 block 5,947,548 2 args Current

Runtime Info

View Source

Pallet Index: 7
Event Index: 14
First Version: v101
Current Version: v393

Back to SubtensorModule Events