NextUnsignedAt

Storage Plain v216 → current

The block number when the next unsigned pulse transaction will be accepted.

Queried by: validatorsdevelopers

The Big Picture

Unsigned transactions are 'free' - no one pays fees. To prevent abuse, the chain only accepts one per block. This storage tracks when the next one is allowed. Offchain workers should check this before submitting to avoid wasted effort.

Why This Matters

If your offchain worker's pulse submissions keep failing, check NextUnsignedAt. If current block < NextUnsignedAt, your unsigned transaction will be rejected. Wait until that block.

Example Scenario

Query NextUnsignedAt() returns 7000100. Current block is 7000099. Your unsigned pulse submission will be rejected - wait one more block. At block 7000100, submit and it succeeds.

Common Questions

Why rate limit unsigned transactions?: Without limits, anyone could spam free transactions. One per block ensures the chain isn't flooded while still allowing regular pulse submission.
What if I need to submit signed instead?: Signed transactions aren't rate-limited this way (they pay fees). If offchain worker timing is problematic, signed submission is an alternative.

Use Cases

Time offchain worker pulse submissions correctly
Debug why pulse submissions are being rejected
Understand rate limiting for unsigned transactions

From Chain Metadata

Defines the block when next unsigned transaction will be accepted. To prevent spam of unsigned (and unpaid!) transactions on the network, we only allow one transaction per block. This storage entry defines when new transaction is going to be accepted.

Purpose & Usage

Purpose

Rate limiting for unsigned pulse submissions to prevent spam.

Common Query Patterns

Check before submitting unsigned pulses
Plan offchain worker timing
Debug pulse submission rate limiting

Notes

Only one unsigned pulse transaction per block allowed
Value updates after each successful unsigned submission
Prevents spam of free (unsigned) transactions

Stored Value

u32

value (u32)

Relationships

Modified By

write_pulse

Related Events

NewPulse

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 NextUnsignedAt storage (no keys - plain value)
const result = await api.query
  [stringCamelCase("Drand")]
  [stringCamelCase("NextUnsignedAt")]();
console.log("NextUnsignedAt:", result.toHuman());

Runtime Info

View Source

Pallet: Drand
Storage Kind: Plain
First Version: v216
Current Version: v393

Back to Drand Storage