batch_commit_weights

Call v216 → current #100

Commits weights on multiple subnets in a single transaction.

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Used by: validatorsdevelopers

The Big Picture

For validators operating across multiple commit-reveal subnets, batch_commit_weights is essential. Instead of N separate commit transactions (with N fees and N confirmations), you submit all commits atomically. This is critical for large validators who might validate on 10+ subnets - the gas savings and operational simplicity are substantial.

Why This Matters

Commit-reveal requires precise timing. Batching commits means one transaction to track, one confirmation to wait for, and one fee to pay. For validators juggling many subnets, this reduces operational complexity and costs significantly.

Example Scenario

You validate on subnets 1, 3, 7, and 18 - all using commit-reveal. After evaluating miners on each, compute hashes: hash1=sha256(weights1+salt1), etc. Call batch_commit_weights(netuids=[1,3,7,18], commits=[hash1,hash2,hash3,hash4]). One transaction, four commits. Now schedule batch_reveal_weights for the reveal windows.

Common Questions

What if commit-reveal windows differ across subnets?
You'll need to reveal in separate batches matching each window, or ensure your batch covers subnets with aligned windows. Mismatched timing requires multiple reveals.
What happens if one commit fails?
Typically the entire batch fails. Ensure all parameters are valid before submitting. Consider using Utility.batch for partial success if needed.
Do I need to remember salts for each subnet?
Yes - each commit has its own salt. Store them securely. Most validator software handles salt management automatically.

Use Cases

  • Multi-subnet validators committing evaluations in one transaction
  • Synchronized commit across related subnets
  • Gas-efficient commit-reveal participation for large validators
  • Operational efficiency for validators on many subnets

From Chain Metadata

Allows a hotkey to commit weight hashes for multiple netuids as a batch.

Input Parameters

#NameTypeDescription
0
netuids
Vec<Compact<u16>> Vecnetuids (Vec<Compact<u16>>)
1
commit_hashes
Vec<H256> Veccommit_hashes (Vec<H256>)

Permissions

Origin
Signed
Required Role
Any

Permission data inferred from metadata. May be incomplete.

Requirements

  • Commit-reveal enabled on target subnets
  • Valid commit hashes for each subnet
  • Validator registered on all target subnets

Effects

Storage Modified

WeightCommitsLastTxBlock

Postconditions

  • Commits stored for all specified subnets
  • Commit timestamps recorded

Side Effects

  • Must reveal each commit separately or in batch
  • Commits expire if not revealed in time

Possible Errors

NotEnoughStakeToSetWeightsWeightVecNotEqualSizeNotSettingEnoughWeightsWeightVecLengthIsLowMaxWeightExceededSettingWeightsTooFastIncorrectWeightVersionKeyCanNotSetRootNetworkWeightsNoWeightsCommitFoundWeightsCommitNotAllowedExpiredWeightCommitCommittingWeightsTooFastAdminActionProhibitedDuringWeightsWindow

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 });

// Build batch_commit_weights call
const netuids = 1;
const commit_hashes = 0 as any /* Vec<H256> */;

const call = api.tx[stringCamelCase("SubtensorModule")][stringCamelCase("batch_commit_weights")](
  netuids,
  commit_hashes
);

Runtime Info

View Source
Pallet Index
7
Call Index
100
First Version
v216
Current Version
v393
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