kill_prefix
Call v101 → current #6Remove all storage items with a given prefix (root only).
View calls on chainCall Workflow
This diagram shows the call execution flow: starting with kill_prefix, passing through validation
(signature, nonce, mortality, fee payment), then pre-dispatch checks, followed by dispatch, and finally post-dispatch where ExtrinsicSuccess is emitted and fees are settled.
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Used by: validatorsdevelopers
The Big Picture
Bulk deletion of storage by prefix. When a pallet is removed, this removes all its storage.
Use Cases
- Remove entire pallet storage
- Clean up all map entries
From Chain Metadata
Kill all storage items with a key that starts with the given prefix. **NOTE:** We rely on the Root origin to provide us the number of subkeys under the prefix we are removing to accurately calculate the weight of this function.
Input Parameters
Permissions
Origin
Unknown
Required Role
Permission data inferred from metadata. May be incomplete.
Requirements
- Caller is root/sudo
- Valid storage prefix
- Accurate subkey count
Effects
Postconditions
- All matching storage items deleted
Side Effects
- Can delete large amounts of data
Code Examples
import { createClient, Binary } from "polkadot-api";
import { getWsProvider } from "polkadot-api/ws";
import { sub } from "@polkadot-api/descriptors"; // generated by: npx papi add sub -w wss://entrypoint-finney.opentensor.ai:443
const client = createClient(getWsProvider("wss://entrypoint-finney.opentensor.ai:443"));
const api = client.getTypedApi(sub);
// Build kill_prefix call (typed, named args)
const prefix = Binary.fromOpaque(new Uint8Array(0));
const subkeys = 0;
const tx = api.tx.System.kill_prefix({
prefix,
subkeys,
});Runtime Info
- Pallet Index
- 0
- Call Index
- 6
- First Version
- v101
- Current Version
- v472