MaxAllowedValidatorsSet

Event Re-added v101 → v127, v133 → v219, v233 → v265, v273 → v277, v290 → current #27

Emitted when maximum validators allowed is changed.

Useful for: validatorssubnet ownersanalyticsdevelopers

The Big Picture

Subnets can limit how many validators participate - not just total neurons, but specifically how many can have validator permits. This affects consensus (more validators = more decentralized but slower). Changes to this limit affect who can validate and validator competition dynamics.

Why This Matters

If you want to validate on a subnet, you need a validator permit. The max validators limit determines how many permits exist. A lower limit means more competition for permits. A higher limit means more opportunity but potentially more diluted rewards.

Example Scenario

Subnet 3 had 64 max validators. To improve decentralization, they increase to 128. MaxAllowedValidatorsSet fires. 64 new validator permit slots open up. If you were waiting for a spot, now's your chance - reduced competition for permits.

Common Questions

What happens if max validators decreases?: Existing validators are typically safe (grandfathered). But new permits aren't issued and natural attrition shrinks the set toward the new limit.
Is max validators the same as max UIDs?: No. MaxAllowedUids is total neurons (miners + validators). MaxAllowedValidators specifically limits how many have validator permits. A subnet could have 256 UIDs but only 64 validators.
How do I become a validator when slots are limited?: You need enough stake to rank in the top MaxAllowedValidators neurons. Below that threshold, you're a miner. Add more stake or wait for validators to leave.

Use Cases

Track validator capacity limits on subnets
Plan validator participation based on availability
Monitor subnet validator policy changes
Build validator opportunity tracking tools

How to Use This Event

→ Monitor validator limits on target subnets
→ Track changes affecting validator competition
→ Build validator slot availability tracking

From Chain Metadata

setting the max number of allowed validators on a subnet.

Triggers

Preconditions

Caller has admin/sudo privileges

Effects

Postconditions

MaxAllowedValidators updated

Side Effects

May affect validator permit distribution

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

Version History

Version:

v101 block 1 2 args

v133 block 1,404,224 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: 27
First Version: v101
Current Version: v393

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