I want to rename one of our collective pallet instances to be visible in the PolkaddotJs App.

I think the best option would be to migrate raw data.

I assume that all pallet data has the same trie path prefix.

So I can do a copy of all keys with this prefix.

Will this approach work?

Rename could be a common operation. Could anybody refer relevant examples?

Another alternative is to have two pallets instances running, filter out calls to old pallet. Migrate each storage using typed interface. I think this approach is overkill. I need actually do this for 2 pallets.

2 Answers 2


I assume that all pallet data has the same trie path prefix.

Yes, this makes it much easier to migration.
There are move_pallet and move_storage_from_pallet which can help.

There is even a test in the collective pallet to test these functions here. Something like:

let old_pallet = "OldCollective";
let new_pallet = <Collective as PalletInfoAccess>::name();

Maybe someone else can point you to best-practices when it comes to renaming pallets.
The only thing that comes to my mind now is that: If you are doing this on a para-chain; it is important that the migration stays within the block weight limit. The try-runtime command prints the consumed weight relative to the block weight on completion so you can use that as indication but should still over-estimate.

  • 1
    AFAIK, there are only a few keys in the collective storage. I think the weight is totally fine.
    – AurevoirXavier
    Dec 2, 2022 at 13:30
  • 1
    Yea but it all goes into the PoV - so if the maps hold a lot of values this will increase. Dec 2, 2022 at 13:33

This is a Substrate/Polkadot "official" pallet prefix migration example.

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