Hi Romain, 409 is not possible, per the Iceberg spec. It would be translated into a "table already exists" error on the client side and wouldn't be retired.
Thanks, Alex On Thu, Jun 11, 2026 at 2:40 PM Romain Manni-Bucau <[email protected]> wrote: > > Hi all > > if it helps 429 is more linked to rate limiting which is misleading there ( > https://www.rfc-editor.org/info/rfc6585/#section-4), 503 to a server error > or state (unavailable) > why not using 409 (conflict) or 412 (precondition failed)? > > hope i'm not too "off topic" > > Romain Manni-Bucau > @rmannibucau <https://x.com/rmannibucau> | .NET Blog > <https://dotnetbirdie.github.io/> | Blog <https://rmannibucau.github.io/> | > Old > Blog <http://rmannibucau.wordpress.com> | Github > <https://github.com/rmannibucau> | LinkedIn > <https://www.linkedin.com/in/rmannibucau> | Book > <https://www.packtpub.com/en-us/product/java-ee-8-high-performance-9781788473064> > Javaccino founder (Java/.NET service - contact via linkedin) > > > Le jeu. 11 juin 2026 à 14:30, Alexandre Dutra <[email protected]> a écrit : > > > The server-side retry idea is interesting, but it won't eliminate the > > problem completely, will it? > > > > If not, I'd suggest pursuing the server-side retry idea as a separate > > effort. > > > > We still need to settle on what status code to return for > > TARGET_ENTITY_CONCURRENTLY_MODIFIED: > > > > - 429 (without the Retry-After header) > > - 503 > > > > I still think 503 is slightly preferable, but won't fight for it either. > > > > Thanks, > > Alex > > > > On Thu, Jun 11, 2026 at 10:24 AM Nándor Kollár <[email protected]> wrote: > > > > > > Thanks, Dmitri, for the explanation. It now makes sense to me to > > > handle the retries on the server side. If there's still a conflict > > > after a couple of retry attempts, then a 429 response code seems > > > reasonable to me. > > > > > > Thanks, > > > Nandor > > > > > > Dmitri Bourlatchkov <[email protected]> ezt írta (időpont: 2026. jún. > > > 11., Cs, 0:06): > > > > > > > > Hi Nandor, > > > > > > > > Rename is fundamentally different from other table operations in that > > it > > > > only affect a catalog-owned piece of data, which is the name. > > > > > > > > Table metadata or properties are not affected. > > > > > > > > I imagine the likely conflict is between a rename and a metadata > > update, > > > > which is conceptually not a client-side conflict. The server should be > > able > > > > to handle it locally. > > > > > > > > However, metadata update conflicts have to bounce to the client > > > > because Polaris cannot resolve them in most cases. The only exception > > AFAIK > > > > is the compact/update conflict [1285]. > > > > > > > > A rename/rename conflict will bounce to the client as a 404 on the > > first > > > > retry. > > > > > > > > [1285] https://github.com/apache/polaris/pull/1285 > > > > > > > > Cheers, > > > > Dmitri. > > > > > > > > On Wed, Jun 10, 2026 at 3:47 PM Nándor Kollár <[email protected]> > > wrote: > > > > > > > > > Hi All, > > > > > > > > > > I'm not against a server-side retry, but I think in that case we > > > > > should do the same for other table update operations no? That sounds > > > > > like a more consistent approach. > > > > > > > > > > Thanks, > > > > > Nandor > > > > > > > > > > Dmitri Bourlatchkov <[email protected]> ezt írta (időpont: 2026. jún. > > > > > 10., Sze, 15:41): > > > > > > > > > > > > Hi All, > > > > > > > > > > > > How about we make Polaris retry the rename a few times on the > > server > > > > > side? > > > > > > If it gets TARGET_ENTITY_CONCURRENTLY_MODIFIED all the times, we > > > > > eventually > > > > > > fail with 429. > > > > > > > > > > > > Prolonged optimistic lock failures probably mean that there are, > > indeed, > > > > > > too many requests. Ideally we should respond with 429 on all > > requests > > > > > > clashing on the entity in question (not just the rename), but I > > guess it > > > > > is > > > > > > not technically feasible ATM. > > > > > > > > > > > > WDYT? > > > > > > > > > > > > Thanks, > > > > > > Dmitri. > > > > > > > > > > > > On Wed, Jun 10, 2026 at 9:10 AM Alexandre Dutra <[email protected] > > > > > > > > wrote: > > > > > > > > > > > > > Hi all, > > > > > > > > > > > > > > I also reviewed the PR and left some comments. Just to summarize > > my > > > > > > > thoughts: > > > > > > > > > > > > > > - ENTITY_CANNOT_BE_RESOLVED and CATALOG_PATH_CANNOT_BE_RESOLVED > > should > > > > > > > be mapped to 404 -> NoSuchNamespaceException. The comments for > > them in > > > > > > > BaseResult are imho inaccurate (they are non-retriable). > > > > > > > > > > > > > > - TARGET_ENTITY_CONCURRENTLY_MODIFIED: unfortunately 409 is > > precluded > > > > > > > because of the Iceberg spec. I am not a big fan of 429 because it > > > > > > > could force clients to throttle. So, I think the current > > proposal of > > > > > > > 503 -> ServiceUnavailableException is the least worst choice (as > > it's > > > > > > > retriable). > > > > > > > > > > > > > > Thanks, > > > > > > > Alex > > > > > > > > > > > > > > On Wed, Jun 10, 2026 at 11:18 AM Nándor Kollár < > > > > > [email protected]> > > > > > > > wrote: > > > > > > > > > > > > > > > > Hi All, > > > > > > > > > > > > > > > > The Iceberg REST spec doesn't appear to define 429 as a valid > > > > > response > > > > > > > > status for rename operations, and I don't think it's an ideal > > choice > > > > > > > > either, since it typically indicates rate-limiting issues > > rather than > > > > > > > > conflicting updates. > > > > > > > > > > > > > > > > In my opinion, 409 would be the most appropriate status code, > > but the > > > > > > > > REST spec reserves it for a different purpose. Perhaps 428 > > > > > > > > Precondition Required could be used to signal a conflict, but > > that > > > > > > > > status is generally intended for GET-then-PUT concurrency > > scenarios, > > > > > > > > which doesn't seem to match this case. > > > > > > > > > > > > > > > > I think we'll be diverging from the Iceberg spec either way, > > since it > > > > > > > > doesn't define a response code for conflicting rename > > operations. > > > > > > > > Given that, it's probably better to use a status code that > > isn't > > > > > > > > defined by the spec at all (such as 429) than to reuse one > > that the > > > > > > > > spec already assigns a different meaning to. Considering this, > > I vote > > > > > > > > for 429 as the least worst option. > > > > > > > > > > > > > > > > As of ENTITY_CANNOT_BE_RESOLVED, it sounds like a 404 for me > > too. > > > > > > > > However, the comment suggests that it may be used for conflict > > > > > > > > scenarios as well, and client should retry: > > > > > > > > > > > > > > > > // the specified entity (and its path) cannot be resolved. > > There is a > > > > > > > > possibility that by the > > > > > > > > // time a call is made by the client to the persistent storage, > > > > > > > > something has changed due to > > > > > > > > // concurrent modification(s). The client should retry in that > > case. > > > > > > > > ENTITY_CANNOT_BE_RESOLVED(4), > > > > > > > > > > > > > > > > Thanks, > > > > > > > > Nandor > > > > > > > > > > > > > > > > Dmitri Bourlatchkov <[email protected]> ezt írta (időpont: > > 2026. jún. > > > > > > > > 10., Sze, 0:43): > > > > > > > > > > > > > > > > > > Hi All, > > > > > > > > > > > > > > > > > > I reviewed PR [4646] (but did not leave any comments in GH, > > > > > replying > > > > > > > here) > > > > > > > > > and the current 500 error is most certainly not correct for > > this > > > > > > > failure > > > > > > > > > mode. 503 is not ideal either, as I commented earlier. > > > > > > > > > > > > > > > > > > From the PR I gather that people are generally uncomfortable > > > > > returning > > > > > > > a > > > > > > > > > 409 response because it has a narrow meaning in the Iceberg > > REST > > > > > API > > > > > > > spec. > > > > > > > > > It is a fair point. > > > > > > > > > > > > > > > > > > Re: the TARGET_ENTITY_CONCURRENTLY_MODIFIED case. How about > > 429 > > > > > (Too > > > > > > > Many > > > > > > > > > Requests)? > > > > > > > > > > > > > > > > > > 429 is clearly retryable and does not carry any implications > > about > > > > > the > > > > > > > > > state of the system after handling the request. > > > > > > > > > > > > > > > > > > The message could say "Unable to rename entity due to > > overlapping > > > > > > > > > concurrent modifications". We do not have to set the > > Retry-After > > > > > > > header. > > > > > > > > > > > > > > > > > > Re: ENTITY_CANNOT_BE_RESOLVED. I believe this is a solid 404 > > case. > > > > > > > > > > > > > > > > > > WDYT? > > > > > > > > > > > > > > > > > > [4646] https://github.com/apache/polaris/pull/4646 > > > > > > > > > > > > > > > > > > Cheers, > > > > > > > > > Dmitri. > > > > > > > > > > > > > > > > > > > > > > > > > > > On Tue, Jun 9, 2026 at 12:02 AM Dmitri Bourlatchkov < > > > > > [email protected]> > > > > > > > > > wrote: > > > > > > > > > > > > > > > > > > > Hi Nandor, > > > > > > > > > > > > > > > > > > > > Good question :) > > > > > > > > > > > > > > > > > > > > I did not read the PR yet, but my gut feel is towards the > > 409 > > > > > error > > > > > > > code > > > > > > > > > > because 5xx generally means a fundamental issue with the > > service > > > > > that > > > > > > > > > > goes beyond the scope of client requests. > > > > > > > > > > > > > > > > > > > > In a more general perspective, traditional HTTP status > > codes are > > > > > > > often too > > > > > > > > > > narrow to express all the API minute error details. My > > personal > > > > > view > > > > > > > is > > > > > > > > > > that a rich payload object in the response can be useful > > in such > > > > > > > cases... > > > > > > > > > > but again that will require a spec change. > > > > > > > > > > > > > > > > > > > > That said, if the request does not require additional > > client > > > > > input > > > > > > > for a > > > > > > > > > > retry, Polaris should retry. I assume we can refactor the > > code to > > > > > > > clearly > > > > > > > > > > distinguish retryable and non-retryable failures on the > > server > > > > > side. > > > > > > > That > > > > > > > > > > part should not require spec changes. > > > > > > > > > > > > > > > > > > > > Cheers, > > > > > > > > > > Dmitri. > > > > > > > > > > > > > > > > > > > > On Mon, Jun 8, 2026 at 9:48 AM Nándor Kollár < > > > > > > > [email protected]> > > > > > > > > > > wrote: > > > > > > > > > > > > > > > > > > > >> Hi all, > > > > > > > > > >> > > > > > > > > > >> I'd like to ask for the community's opinion on the > > appropriate > > > > > > > > > >> response status code for table/view rename operations when > > > > > there is > > > > > > > a > > > > > > > > > >> conflicting operation in progress. > > > > > > > > > >> > > > > > > > > > >> A PR was recently raised [1], which I believe highlighted > > the > > > > > > > question > > > > > > > > > >> of what the correct status code should be in such conflict > > > > > > > scenarios. > > > > > > > > > >> To me, the Iceberg REST Catalog specification does not > > clearly > > > > > > > address > > > > > > > > > >> this case. Neither 409 Conflict nor 503 Service > > Unavailable > > > > > seems > > > > > > > > > >> entirely appropriate for indicating to the client that the > > > > > operation > > > > > > > > > >> could not be completed due to a conflict and that > > retrying the > > > > > > > > > >> operation may succeed. > > > > > > > > > >> > > > > > > > > > >> I think 409 Conflict might be the better choice, but that > > would > > > > > > > > > >> require a change to the specification. It would also end > > up > > > > > serving > > > > > > > > > >> two different purposes: a non-retriable scenario, where > > the > > > > > target > > > > > > > > > >> name is already reserved, and a retriable scenario, where > > the > > > > > > > > > >> operation failed due to a temporary conflict. What do you > > think? > > > > > > > > > >> > > > > > > > > > >> [1] https://github.com/apache/polaris/pull/4646 > > > > > > > > > >> > > > > > > > > > >> Thanks, > > > > > > > > > >> Nandor > > > > > > > > > >> > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > -- > > > > > > > > Kollár Nándor > > > > > > > > > > > > > >
