LastUpdate

Storage Map v101 → current

Block number of last weight update for a neuron .

Queried by: validatorsdevelopersanalytics

The Big Picture

Active validators update weights regularly to reflect current network state. This timestamp shows when each neuron last updated. Stale weights (many blocks old) suggest inactive or poorly maintained validators - important for delegation decisions.

Why This Matters

Is this validator actively maintaining their weights, or set-and-forget? Recent LastUpdate means active participation. Old LastUpdate is a red flag.

Example Scenario

Current block is 7,000,000. Query LastUpdate(netuid=1, uid=5) returns 6,999,950. Validator updated 50 blocks ago - very active. If it returned 6,900,000, that's 100,000 blocks stale - concerning.

Common Questions

How fresh should weights be?: Depends on the subnet's tempo. Generally, weights should update at least once per epoch. Check subnet parameters for specific expectations.
What's the rate limit?: Check WeightsSetRateLimit for the subnet. You typically can't update more than once per N blocks.

Use Cases

Check if validator is actively updating weights
Determine when weights can be updated again (rate limiting)
Identify stale or inactive validators
Build validator activity monitoring dashboards

Purpose & Usage

Purpose

Track weight freshness and rate limiting.

Common Query Patterns

Check if weights are stale
Verify rate limit compliance

Part of: Epoch Processing

Query Keys

#	Name	Type	Description
1	key1 → netuid	u16	Subnet ID

Stored Value

Vec<u64> Vec

Block numbers of last update per UID

Relationships

Modified By

batch_reveal_weights batch_set_weights reveal_mechanism_weights reveal_weights set_mechanism_weights set_weights

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 });

// Query LastUpdate storage
const key1 = 0;

const result = await api.query
  [stringCamelCase("SubtensorModule")]
  [stringCamelCase("LastUpdate")](
  key1
);

console.log("LastUpdate:", result.toHuman());

On-Chain Activity

Write Frequency

●●●●●● Ultra-High >10M est. writes

>10M estimated writes

#2 most written storage item

Write Source Calls + Hooks

Modified by both user extrinsics and runtime hooks

As of block 7,429,232

Runtime Info

View Source

Pallet: SubtensorModule
Storage Kind: Map
First Version: v101
Current Version: v393

Back to SubtensorModule Storage