Hi Aritra,

Thanks for starting this discussion. It's a very interesting feature.

>From my POV I see two sub-topics, where I hope for broader community
engagement.

1) Credential Vending for Federated IRC catalogs in principle.

IIRC, this PR builds on top of fedetrating to AWS S3 tables via the Iceberg
REST Catalog API.

Does AWS support credential vending in their IRC implementation?

If yes, should Polaris merely channel them to the client instead of minting
different credentials?

If no, should Polaris treat S3 tables as a sub-type of S3 storage? I see
some similarities to normal S3 + STS use case, at the same time the ARNs
scheme is different and policies are different. This creates too many
if/else constructs in the existing storage integration code, so I hope it
might be possible to refactor that and leverate polymorphism to reduce
if/else branches.

2) As I noted in GH comments, the current POC code uses different channels
for passing S3 table locations and normal S3 bucket locations. I believe it
is time to refactor that part of Polaris to represent both use cases on the
same call path leading to the storage integration code.

Tornike has draft PR [3699], which seems to be moving in a generally
compatible direction. I hope we can make progress on that refactoring,
benefiting the S3 tables too.

[3699] https://github.com/apache/polaris/pull/3699

Cheers,
Dmitri.

On Tue, Mar 24, 2026 at 5:46 PM Gupta, Aritra <[email protected]> wrote:

> Dear All,
>
> With Polaris 1.3, SigV4 auth support was added for federated catalogs,
> which is great. I've been trying to use this to federate Polaris to Amazon
> S3 Tables, but wasn't able to make it fully work. Metadata operations like
> listing namespaces and loading tables work fine through federation, but
> credential vending breaks because S3 Tables uses a different IAM action
> namespace (s3tables:) and ARN format than standard S3. The existing session
> policy logic hardcodes s3: actions, so the policy intersection ends up
> empty and clients get ACCESS_DENIED on data access.
>
> I've put together a directional first-cut draft PR that adds S3 Tables
> credential vending support. The approach auto-detects S3 Tables catalogs
> from the signingName in the SigV4 connection config, so no additional user
> configuration is needed beyond what's already required for federation.
>
> This is very much a starting point, and there's more work needed around
> integration testing, documentation, and code cleanup. I'd really appreciate
> the community's input on whether the overall direction makes sense, and any
> help or feedback from folks who have context on the credential vending flow
> would be wonderful.
>
> Looking forward to the discussion!
>
> Links:
>
> Draft PR: https://github.com/apache/polaris/pull/4052
> Related Issue: https://github.com/apache/polaris/issues/577
>
> Best,
> Aritra Gupta
>
>

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