Sounds good. I don't really have any strong opinions here. So looks like we are landing on this?
*PreplanTable: POST /v1/namespaces/ns/tables/t/preplan*{ "filter": { "type": "in", "term": "x", "values": [1, 2, 3] }, "select": ["x", "a.b"] } { "plan-tasks": [ { ... }, { ... } ] } // opaque object *PlanTable w/o a plan task: POST /v1/namespaces/ns/tables/t/plan*{ "filter": {"type": "in", "term": "x", "values": [1, 2, 3] }, "select": ["x", "a.b"] } { "file-scan-tasks": [ { ... }, { ... } ] } // FileScanTask OpenAPI model *PlanTable w/ a plan task: POST /v1/namespaces/ns/tables/t/plan*{ "filter": {"type": "in", "term": "x", "values": [1, 2, 3] }, "select": ["x", "a.b"], "plan-task": { ... } } { "file-scan-tasks": [ { ... }, { ... } ] } -Jack On Wed, Jan 31, 2024 at 10:08 AM Ryan Blue <b...@tabular.io> wrote: > I agree with Dan. I'd rather have two endpoints instead of needing an > option that changes the behavior entirely in the same route. I don't think > that a `preplan` route would be too bad. > > On Wed, Jan 31, 2024 at 9:51 AM Daniel Weeks <dwe...@apache.org> wrote: > >> I agree with the opaque tokens. >> >> However, I'm concerned we're overloading the endpoint two perform two >> distinctly different operations: distribute a plan and scan a plan. >> >> Changing the task-type then changes the behavior and the result. I feel >> it would be more straightforward to separate the distribute and scan >> endpoints. Then clients can call the scan directly if they do not know how >> to distribute and the behavior is clear from the REST Specification. >> >> -Dan >> >> On Tue, Jan 30, 2024 at 9:09 PM Jack Ye <yezhao...@gmail.com> wrote: >> >>> +1 for having the opaque plan tasks, that's probably the most flexible >>> way forward. And let's call them *plan tasks* going forward to >>> standardize the terminology. >>> >>> I think the name of the APIs can be determined based on the actual API >>> shape. For example, if we centralize these 2 plan and pre-plan actions to a >>> single API endpoint but just requesting different task types: >>> >>> >>> *pre-plan: POST /v1/namespaces/ns/tables/t/plan*{ "filter": { "type": >>> "in", "term": "x", "values": [1, 2, 3] }, "select": ["x", "a.b"], >>> "task-type": "plan-task" } >>> >>> { "plan-tasks": [ { ... }, { ... } ] } >>> >>> >>> *plan without a plan-task: POST /v1/namespaces/ns/tables/t/plan*{ >>> "filter": {"type": "in", "term": "x", "values": [1, 2, 3] }, "select": >>> ["x", "a.b"], "task-type": "file-scan-task" } // file-scan-task should be >>> the default type >>> >>> { "file-scan-tasks": [ { ... }, { ... } ] } >>> >>> >>> *plan with a plan-task: POST /v1/namespaces/ns/tables/t/plan*{ >>> "filter": {"type": "in", "term": "x", "values": [1, 2, 3] }, "select": >>> ["x", "a.b"], "task-type": "file-scan-task", "plan-task": { ... } } >>> >>> { "file-scan-tasks": [...] } >>> >>> In this model, we just have a single API, and we can call it something >>> like PlanTable or PlanTableScan. >>> >>> What do you think? >>> >>> -Jack >>> >>> >>> On Mon, Jan 29, 2024 at 6:17 PM Renjie Liu <liurenjie2...@gmail.com> >>> wrote: >>> >>>> But to move forward, I think we should go with the option that >>>>> preserves flexibility. I think the spec should state that plan tasks (if >>>>> we >>>>> call them that) are a JSON object that should be sent as-is back to the >>>>> REST service to be used. >>>> >>>> >>>> +1 for this. >>>> >>>> > One more thing that I would also change is that I don't think the >>>> "plan" and "scan" endpoints make much sense. We refer to the "scan" portion >>>> of this as "planFiles" in the reference implementation, and "scan" is used >>>> for actually reading data. To be less confusing, I think that file scan >>>> tasks should be returned by a "plan" endpoint and the manifest plan tasks >>>> (or shards) should be returned by a "pre-plan" endpoint. Does anyone else >>>> like the names "pre-plan" and "plan" better? >>>> >>>> I agree that "scan" may be quite confusing since it's actually planning >>>> file scan. Another options I can provide is: "plan" -> "plan-table-scan", >>>> "scan" -> "plan-file-scan" >>>> >>>> >>>> >>>> >>>> On Tue, Jan 30, 2024 at 9:03 AM Ryan Blue <b...@tabular.io> wrote: >>>> >>>>> As you noted the main point we still need to decide on is whether to >>>>> have a standard "shard" definition (e.g. manifest plan task) or to allow >>>>> it >>>>> to be opaque and specific to catalogs implementing the protocol. I've not >>>>> replied because I keep coming back to this decision and I'm not sure >>>>> whether the advantage is being clear about how it works (being explicit) >>>>> or >>>>> allowing implementations to differ (opaque). I'm skeptical that there will >>>>> be other strategies. >>>>> >>>>> But to move forward, I think we should go with the option that >>>>> preserves flexibility. I think the spec should state that plan tasks (if >>>>> we >>>>> call them that) are a JSON object that should be sent as-is back to the >>>>> REST service to be used. >>>>> >>>>> One more thing that I would also change is that I don't think the >>>>> "plan" and "scan" endpoints make much sense. We refer to the "scan" >>>>> portion >>>>> of this as "planFiles" in the reference implementation, and "scan" is used >>>>> for actually reading data. To be less confusing, I think that file scan >>>>> tasks should be returned by a "plan" endpoint and the manifest plan tasks >>>>> (or shards) should be returned by a "pre-plan" endpoint. Does anyone else >>>>> like the names "pre-plan" and "plan" better? >>>>> >>>>> Ryan >>>>> >>>>> On Mon, Jan 29, 2024 at 12:02 PM Chertara, Rahil >>>>> <rcher...@amazon.com.invalid> wrote: >>>>> >>>>>> Hi All hope everyone is doing well, >>>>>> >>>>>> >>>>>> Wanted to revive the discussion around the Rest Table Scan API work. >>>>>> For a refresher here is the original proposal: >>>>>> https://docs.google.com/document/d/1FdjCnFZM1fNtgyb9-v9fU4FwOX4An-pqEwSaJe8RgUg/edit#heading=h.cftjlkb2wh4h >>>>>> as well as the PR: https://github.com/apache/iceberg/pull/9252 >>>>>> >>>>>> >>>>>> From the last messages on the thread, I believe Ryan and Jack were in >>>>>> favor of having two distinct api endpoints /plan and /scan, as well as a >>>>>> stricter json definition for the "shard”, here is an example below from >>>>>> what was discussed. >>>>>> >>>>>> >>>>>> *POST /v1/namespaces/ns/tables/t/plan *{ "filter": { "type": "in", >>>>>> "term": "x", "values": [1, 2, 3] }, "select": ["x", "a.b"]} >>>>>> >>>>>> { "manifest-plan-tasks": [ >>>>>> { "start": 0, "length": 1000, "manifest": { "path": >>>>>> "s3://some/manifest.avro", ...}, "delete-manifests": [...] }, >>>>>> { ... } >>>>>> ]} >>>>>> >>>>>> >>>>>> *POST /v1/namespaces/ns/tables/t/scan *{ "filter": {"type": "in", >>>>>> "term": "x", "values": [1, 2, 3] }, >>>>>> >>>>>> "select": ["x", "a.b"], >>>>>> "manifest-plan-task": { "start": 0, "length": 1000, "manifest": { >>>>>> "path": "s3://some/manifest.avro", ...}, "delete-manifests": [...] } } >>>>>> >>>>>> { "file-scan-tasks": [...] } >>>>>> >>>>>> >>>>>> *POST /v1/namespaces/ns/tables/t/scan *{ "filter": {"type": "in", >>>>>> "term": "x", "values": [1, 2, 3] }, "select": ["x", "a.b"]} >>>>>> >>>>>> >>>>>> { "file-scan-tasks": [...] } >>>>>> >>>>>> >>>>>> >>>>>> However IIRC Micah and Renjie had some concerns around this stricter >>>>>> structure as this can make it harder to evolve in the future, as well as >>>>>> some potential scalability challenges for larger tables that have many >>>>>> manifest files. (Feel free to expand further on the concerns if my >>>>>> understanding is incorrect). >>>>>> >>>>>> >>>>>> >>>>>> Would appreciate if the community can leave any more >>>>>> thoughts/feedback on this thread, as well as on the google doc, and the >>>>>> PR. >>>>>> >>>>>> >>>>>> >>>>>> Regards, >>>>>> Rahil Chertara >>>>>> >>>>>> >>>>>> >>>>>> *From: *Renjie Liu <liurenjie2...@gmail.com> >>>>>> *Reply-To: *"dev@iceberg.apache.org" <dev@iceberg.apache.org> >>>>>> *Date: *Thursday, December 21, 2023 at 10:35 PM >>>>>> *To: *"dev@iceberg.apache.org" <dev@iceberg.apache.org> >>>>>> *Subject: *RE: [EXTERNAL] Proposal for REST APIs for Iceberg table >>>>>> scans >>>>>> >>>>>> >>>>>> >>>>>> *CAUTION*: This email originated from outside of the organization. >>>>>> Do not click links or open attachments unless you can confirm the sender >>>>>> and know the content is safe. >>>>>> >>>>>> >>>>>> >>>>>> I share the same concern with Micah. The shard detail should be >>>>>> implementation details of the server, rather than exposing directly to >>>>>> the >>>>>> client. If the goal is to make things stateless, we just need to attach a >>>>>> snapshot id + shard id, then a determined algorithm is supposed to give >>>>>> the >>>>>> same result. Also another concern is for huge analytics tables, we may >>>>>> have >>>>>> a lot of manifest files, which may lead to large traffic from the rest >>>>>> server. >>>>>> >>>>>> >>>>>> >>>>>> On Thu, Dec 21, 2023 at 7:41 AM Micah Kornfield < >>>>>> emkornfi...@gmail.com> wrote: >>>>>> >>>>>> Also +1 for having a more strict definition of the shard. Having >>>>>> arbitrary JSON was basically what we experimented with a string shard ID, >>>>>> and we ended up with something very similar to the manifest plan task you >>>>>> describe in the serialized ID string. >>>>>> >>>>>> >>>>>> >>>>>> IIUC the proposal correctly, I'd actually be -0.0 on the stricter >>>>>> structure. I think forcing a contract where it isn't strictly necessary >>>>>> makes it harder to evolve the system in the future. For example it makes >>>>>> it harder to address potential scalability problems in a transparent way >>>>>> (e.g. extreme edge cases in cardinality between manifest files and delete >>>>>> files). >>>>>> >>>>>> >>>>>> >>>>>> It also seems like it might overly constrain implementations (it is >>>>>> not clear we should need to compute the mapping between delete file >>>>>> manifests to data file manifests up front to start planning). >>>>>> >>>>>> >>>>>> >>>>>> On Tue, Dec 19, 2023 at 2:10 PM Jack Ye <yezhao...@gmail.com> wrote: >>>>>> >>>>>> +1 for having /plan and /scan, sounds like a good idea to separate >>>>>> those 2 distinct actions. >>>>>> >>>>>> >>>>>> >>>>>> Also +1 for having a more strict definition of the shard. Having >>>>>> arbitrary JSON was basically what we experimented with a string shard ID, >>>>>> and we ended up with something very similar to the manifest plan task you >>>>>> describe in the serialized ID string. >>>>>> >>>>>> >>>>>> >>>>>> So sounds like we are converging to the following APIs: >>>>>> >>>>>> >>>>>> >>>>>> >>>>>> *POST /v1/namespaces/ns/tables/t/plan *{ "filter": { "type": "in", >>>>>> "term": "x", "values": [1, 2, 3] }, "select": ["x", "a.b"]} >>>>>> >>>>>> { "manifest-plan-tasks": [ >>>>>> { "start": 0, "length": 1000, "manifest": { "path": >>>>>> "s3://some/manifest.avro", ...}, "delete-manifests": [...] }, >>>>>> { ... } >>>>>> ]} >>>>>> >>>>>> >>>>>> *POST /v1/namespaces/ns/tables/t/scan *{ "filter": {"type": "in", >>>>>> "term": "x", "values": [1, 2, 3] }, >>>>>> >>>>>> "select": ["x", "a.b"], >>>>>> "manifest-plan-task": { "start": 0, "length": 1000, "manifest": { >>>>>> "path": "s3://some/manifest.avro", ...}, "delete-manifests": [...] } } >>>>>> >>>>>> { "file-scan-tasks": [...] } >>>>>> >>>>>> >>>>>> *POST /v1/namespaces/ns/tables/t/scan *{ "filter": {"type": "in", >>>>>> "term": "x", "values": [1, 2, 3] }, "select": ["x", "a.b"]} >>>>>> >>>>>> >>>>>> { "file-scan-tasks": [...] } >>>>>> >>>>>> >>>>>> >>>>>> If this sounds good overall, we can update the prototype to have more >>>>>> detailed discussions in code. >>>>>> >>>>>> >>>>>> >>>>>> -Jack >>>>>> >>>>>> >>>>>> >>>>>> >>>>>> >>>>>> >>>>>> >>>>>> >>>>>> >>>>>> >>>>>> >>>>>> On Thu, Dec 14, 2023 at 6:10 PM Ryan Blue <b...@tabular.io> wrote: >>>>>> >>>>>> The tasks might look something like this: >>>>>> >>>>>> >>>>>> >>>>>> CombinedPlanTask >>>>>> >>>>>> - List<ManifestPlanTask> >>>>>> >>>>>> >>>>>> >>>>>> ManifestPlanTask >>>>>> >>>>>> - int start >>>>>> >>>>>> - int length >>>>>> >>>>>> - ManifestFile dataManifest >>>>>> >>>>>> - List<ManifestFile> deleteManifests >>>>>> >>>>>> >>>>>> >>>>>> On Thu, Dec 14, 2023 at 4:07 PM Ryan Blue <b...@tabular.io> wrote: >>>>>> >>>>>> Seems like that track has expired (This Internet-Draft will expire on >>>>>> 13 May 2022) >>>>>> >>>>>> Yeah, looks like we should just use POST. That’s too bad. QUERY seems >>>>>> like a good idea to me. >>>>>> >>>>>> Distinguish planning using shard or not >>>>>> >>>>>> I think this was a mistake on my part. I was still thinking that we >>>>>> would have a different endpoint for first-level planning to produce >>>>>> shards >>>>>> and the route to actually get files. Since both are POST requests with >>>>>> the >>>>>> same path (/v1/namespaces/ns/tables/t/scans) that no longer works. >>>>>> What about /v1/namespaces/ns/tables/t/scan and >>>>>> /v1/namespaces/ns/tables/t/plan? The latter could use some variant >>>>>> of planFiles since that’s what we are wrapping in the Java API. >>>>>> >>>>>> Necessity of scan ID >>>>>> >>>>>> Yes, I agree. If you have shard IDs then you don’t really need a scan >>>>>> ID. You could always have one internally but send it as part of the shard >>>>>> ID. >>>>>> >>>>>> Shape of shard payload >>>>>> >>>>>> I think we have 2 general options depending on how strict we want to >>>>>> be. >>>>>> >>>>>> 1. Require a standard shard definition >>>>>> 2. Allow arbitrary JSON and leave it to the service >>>>>> >>>>>> I lean toward the first option, which would be a data manifest and >>>>>> the associated delete manifests for the partition. We could also extend >>>>>> that to a group of manifests, each with a list of delete manifests. And >>>>>> we >>>>>> could also allow splitting to ensure tasks don’t get too large with big >>>>>> files. This all looks basically like FileScanTask, but with manifests and >>>>>> delete manifests. >>>>>> >>>>>> >>>>>> >>>>>> On Wed, Dec 13, 2023 at 4:39 PM Jack Ye <yezhao...@gmail.com> wrote: >>>>>> >>>>>> Seems like that track has expired (This Internet-Draft will expire on >>>>>> 13 May 2022), not sure how these RFCs are managed, but it does not seem >>>>>> hopeful to have this verb in. I think people are mostly using POST for >>>>>> this >>>>>> use case already. >>>>>> >>>>>> >>>>>> >>>>>> But overall I think we are in agreement with the general direction. A >>>>>> few detail discussions: >>>>>> >>>>>> >>>>>> >>>>>> *Distinguish planning using shard or not* >>>>>> >>>>>> Maybe we should add a query parameter like *distributed=true* to >>>>>> distinguish your first and third case, since they are now sharing the >>>>>> same >>>>>> signature. If the requester wants to use distributed planning, then some >>>>>> sharding strategy is provided as a response for the requester to send >>>>>> more >>>>>> detailed requests. >>>>>> >>>>>> *Necessity of scan ID* >>>>>> In this approach, is scan ID still required? Because the shard >>>>>> payload already fully describes the information to retrieve, it seems >>>>>> like >>>>>> we can just drop the *scan-id* query parameter in the second case. >>>>>> Seems like it's kept for the case if we still want to persist some state, >>>>>> but it seems like we can make a stateless style fully working. >>>>>> >>>>>> *Shape of shard payload* >>>>>> What do you think is necessary information of the shard payload? It >>>>>> seems like we need at least the location of the manifests, plus the >>>>>> delete >>>>>> manifests or delete files associated with the manifests. I like the idea >>>>>> of >>>>>> making it a "shard task" that is similar to a file scan task, and it >>>>>> might >>>>>> allow us to return a mixture of both types of tasks, so we can have >>>>>> better >>>>>> control of the response size. >>>>>> >>>>>> -Jack >>>>>> >>>>>> >>>>>> >>>>>> On Wed, Dec 13, 2023 at 3:50 PM Ryan Blue <b...@tabular.io> wrote: >>>>>> >>>>>> I just changed it to POST after looking into support for the QUERY >>>>>> method. It's a new HTTP method for cases like this where you don't want >>>>>> to >>>>>> pass everything through query params. Here's the QUERY method RFC >>>>>> <https://www.ietf.org/archive/id/draft-ietf-httpbis-safe-method-w-body-02.html>, >>>>>> but I guess it isn't finalized yet? >>>>>> >>>>>> >>>>>> >>>>>> Just read them like you would a POST request that doesn't actually >>>>>> create anything. >>>>>> >>>>>> >>>>>> >>>>>> On Wed, Dec 13, 2023 at 3:45 PM Jack Ye <yezhao...@gmail.com> wrote: >>>>>> >>>>>> Thanks, the Gist explains a lot of things. This is actually very >>>>>> close to our way of implementing the shard ID, we were defining the shard >>>>>> ID as a string, and the string content is actually something similar to >>>>>> the >>>>>> information of the JSON payload you showed, so we can persist minimum >>>>>> information in storage. >>>>>> >>>>>> >>>>>> >>>>>> Just one clarification needed for your Gist: >>>>>> >>>>>> >>>>>> >>>>>> > QUERY /v1/namespaces/ns/tables/t/scans?scan-id=1 >>>>>> >>>>>> >>>>>> >>>>>> > { "shard": { "id": 1, "manifests": ["C"] }, "filter": {"type": >>>>>> "in", "term": "x", "values": [1, 2, 3] } } >>>>>> >>>>>> >>>>>> >>>>>> > >>>>>> >>>>>> > { "file-scan-tasks": [...] } >>>>>> >>>>>> >>>>>> >>>>>> Here, what does this QUERY verb mean? Is that a GET? If it's GET, we >>>>>> cannot have a request body. That's actually why we expressed that as an >>>>>> ID >>>>>> string, since we can put it as a query parameter. >>>>>> >>>>>> >>>>>> >>>>>> -Jack >>>>>> >>>>>> >>>>>> >>>>>> >>>>>> >>>>>> >>>>>> >>>>>> >>>>>> >>>>>> >>>>>> >>>>>> >>>>>> >>>>>> >>>>>> >>>>>> >>>>>> >>>>>> >>>>>> >>>>>> On Wed, Dec 13, 2023 at 3:25 PM Ryan Blue <b...@tabular.io> wrote: >>>>>> >>>>>> Jack, >>>>>> >>>>>> It sounds like what I’m proposing isn’t quite clear because your >>>>>> initial response was arguing for a sharding capability. I agree that >>>>>> sharding is a good idea. I’m less confident about two points: >>>>>> >>>>>> 1. Requiring that the service is stateful. As Renjie pointed out, >>>>>> that makes it harder to scale the service. >>>>>> 2. The need for both pagination *and* sharding as separate things >>>>>> >>>>>> And I also think that Fokko has a good point about trying to keep >>>>>> things simple and not requiring the CreateScan endpoint. >>>>>> >>>>>> For the first point, I’m proposing that we still have a CreateScan >>>>>> endpoint, but instead of sending only a list of shard IDs it can also >>>>>> send >>>>>> either a standard shard “task” or an optional JSON definition. Let’s >>>>>> assume >>>>>> we can send arbitrary JSON for an example. Say I have a table with 4 >>>>>> manifests, A through D and that C and D match some query filter. >>>>>> When I call the CreateScan endpoint, the service would send back >>>>>> tasks with that information: {"id": 1, "manifests": ["C"]}, {"id": >>>>>> 2, "manifests": ["D"]}. By sending what the shards mean (the >>>>>> manifests to read), my service can be stateless: any node can get a >>>>>> request >>>>>> for shard 1, read manifest C, and send back the resulting data files. >>>>>> >>>>>> I don’t see much of an argument against doing this *in principle*. >>>>>> It gives you the flexibility to store state if you choose or to send >>>>>> state >>>>>> to the client for it to pass back when calling the GetTasks >>>>>> endpoint. There is a practical problem, which is that it’s annoying to >>>>>> send >>>>>> a GET request with a JSON payload because you can’t send a request body. >>>>>> It’s probably obvious, but I’m also not a REST purist so I’d be fine >>>>>> using >>>>>> POST or QUERY for this. It would look something like this Gist >>>>>> <https://gist.github.com/rdblue/d2b65bd2ad20f85ee9d04ccf19ac8aba>. >>>>>> >>>>>> In your last reply, you also asked whether a stateless service is a >>>>>> goal. I don’t think that it is, but if we can make simple changes to the >>>>>> spec to allow more flexibility on the server side, I think that’s a good >>>>>> direction. You also asked about a reference implementation and I consider >>>>>> CatalogHandlers >>>>>> <https://github.com/apache/iceberg/blob/main/core/src/main/java/org/apache/iceberg/rest/CatalogHandlers.java> >>>>>> to be that reference. It does everything except for the work done by your >>>>>> choice of web application framework. It isn’t stateless, but it only >>>>>> relies >>>>>> on a Catalog implementation for persistence. >>>>>> >>>>>> For the second point, I don’t understand why we need both sharding >>>>>> and pagination. That is, if we have a protocol that allows sharding, why >>>>>> is >>>>>> pagination also needed? From my naive perspective on how sharding would >>>>>> work, we should be able to use metadata from the manifest list to limit >>>>>> the >>>>>> potential number of data files in a given shard. As long as we can limit >>>>>> the size of a shard to produce more, pagination seems like unnecessary >>>>>> complication. >>>>>> >>>>>> Lastly, for Fokko’s point, I think another easy extension to the >>>>>> proposal is to support a direct call to GetTasks. There’s a >>>>>> trade-off here, but if you’re already sending the original filter along >>>>>> with the request (in order to filter records from manifest C for >>>>>> instance) then the request is already something the protocol can express. >>>>>> There’s an objection concerning resource consumption on the service and >>>>>> creating responses that are too large or take too long, but we can get >>>>>> around that by responding with a code that instructs the client to use >>>>>> the >>>>>> CreateScan API like 413 (Payload too large). I think that would >>>>>> allow simple clients to function for all but really large tables. The >>>>>> gist >>>>>> above also shows what this might look like. >>>>>> >>>>>> Ryan >>>>>> >>>>>> >>>>>> >>>>>> On Wed, Dec 13, 2023 at 11:53 AM Jack Ye <yezhao...@gmail.com> wrote: >>>>>> >>>>>> The current proposal definitely makes the server stateful. In our >>>>>> prototype we used other components like DynamoDB to keep track of states. >>>>>> If keeping it stateless is a tenant we can definitely make the proposal >>>>>> closer to that direction. Maybe one thing to make sure is, is this a core >>>>>> tenant of the REST spec? Today we do not even have an official reference >>>>>> implementation of the REST server, I feel it is hard to say what are the >>>>>> core tenants. Maybe we should create one? >>>>>> >>>>>> >>>>>> >>>>>> Pagination is a common issue in the REST spec. We also see similar >>>>>> limitations with other APIs like GetTables, GetNamespaces. When a catalog >>>>>> has many namespaces and tables it suffers from the same issue. It is also >>>>>> not ideal for use cases like web browsers, since typically you display a >>>>>> small page of results and do not need the full list immediately. So I >>>>>> feel >>>>>> we cannot really avoid some state to be kept for those use cases. >>>>>> >>>>>> >>>>>> >>>>>> Chunked response might be a good way to work around it. We also >>>>>> thought about using HTTP2. However, these options seem to be not very >>>>>> compatible with OpenAPI. We can do some further research in this domain, >>>>>> would really appreciate it if anyone has more insights and experience >>>>>> with >>>>>> OpenAPI that can provide some suggestions. >>>>>> >>>>>> >>>>>> >>>>>> -Jack >>>>>> >>>>>> >>>>>> >>>>>> >>>>>> >>>>>> >>>>>> >>>>>> On Tue, Dec 12, 2023 at 6:21 PM Renjie Liu <liurenjie2...@gmail.com> >>>>>> wrote: >>>>>> >>>>>> Hi, Rahi and Jack: >>>>>> >>>>>> Thanks for raising this. >>>>>> >>>>>> >>>>>> >>>>>> My question is that the pagination and sharding will make the rest >>>>>> server stateful, e.g. a sequence of calls is required to go to the same >>>>>> server. In this case, how do we ensure the scalability of the rest >>>>>> server? >>>>>> >>>>>> >>>>>> >>>>>> >>>>>> >>>>>> On Wed, Dec 13, 2023 at 4:09 AM Fokko Driesprong <fo...@apache.org> >>>>>> wrote: >>>>>> >>>>>> Hey Rahil and Jack, >>>>>> >>>>>> >>>>>> >>>>>> Thanks for bringing this up. Ryan and I also discussed this briefly >>>>>> in the early days of PyIceberg and it would have helped a lot in the >>>>>> speed >>>>>> of development. We went for the traditional approach because that would >>>>>> also support all the other catalogs, but now that the REST catalog is >>>>>> taking off, I think it still makes a lot of sense to get it in. >>>>>> >>>>>> >>>>>> >>>>>> I do share the concern raised Ryan around the concepts of shards and >>>>>> pagination. For PyIceberg (but also for Go, Rust, and DuckDB) that are >>>>>> living in a single process today the concept of shards doesn't add >>>>>> value. I >>>>>> see your concern with long-running jobs, but for the non-distributed >>>>>> cases, >>>>>> it will add additional complexity. >>>>>> >>>>>> >>>>>> >>>>>> Some suggestions that come to mind: >>>>>> >>>>>> - Stream the tasks directly back using a chunked >>>>>> response, reducing the latency to the first task. This would also >>>>>> solve >>>>>> things with the pagination. The only downside I can think of is having >>>>>> delete files where you first need to make sure there are deletes >>>>>> relevant >>>>>> to the task, this might increase latency to the first task. >>>>>> - Making the sharding optional. If you want to shard you call the >>>>>> CreateScan first and then call the GetScanTask with the IDs. If you >>>>>> don't >>>>>> want to shard, you omit the shard parameter and fetch the tasks >>>>>> directly >>>>>> (here we need also replace the scan string with the full >>>>>> column/expression/snapshot-id etc). >>>>>> >>>>>> Looking forward to discussing this tomorrow in the community sync >>>>>> <https://iceberg.apache.org/community/#iceberg-community-events>! >>>>>> >>>>>> >>>>>> >>>>>> Kind regards, >>>>>> >>>>>> Fokko >>>>>> >>>>>> >>>>>> >>>>>> >>>>>> >>>>>> >>>>>> >>>>>> Op ma 11 dec 2023 om 19:05 schreef Jack Ye <yezhao...@gmail.com>: >>>>>> >>>>>> Hi Ryan, thanks for the feedback! >>>>>> >>>>>> >>>>>> >>>>>> I was a part of this design discussion internally and can provide >>>>>> more details. One reason for separating the CreateScan operation was to >>>>>> make the API asynchronous and thus keep HTTP communications short. >>>>>> Consider >>>>>> the case where we only have GetScanTasks API, and there is no shard >>>>>> specified. It might take tens of seconds, or even minutes to read through >>>>>> all the manifest list and manifests before being able to return anything. >>>>>> This means the HTTP connection has to remain open during that period, >>>>>> which >>>>>> is not really a good practice in general (consider connection failure, >>>>>> load >>>>>> balancer and proxy load, etc.). And when we shift the API to >>>>>> asynchronous, >>>>>> it basically becomes something like the proposal, where a stateful ID is >>>>>> generated to be able to immediately return back to the client, and the >>>>>> client get results by referencing the ID. So in our current prototype >>>>>> implementation we are actually keeping this ID and the whole REST service >>>>>> is stateful. >>>>>> >>>>>> >>>>>> >>>>>> There were some thoughts we had about the possibility to define a >>>>>> "shard ID generator" protocol: basically the client agrees with the >>>>>> service >>>>>> a way to deterministically generate shard IDs, and service uses it to >>>>>> create shards. That sounds like what you are suggesting here, and it >>>>>> pushes >>>>>> the responsibility to the client side to determine the parallelism. But >>>>>> in >>>>>> some bad cases (e.g. there are many delete files and we need to read all >>>>>> those in each shard to apply filters), it seems like there might still be >>>>>> the long open connection issue above. What is your thought on that? >>>>>> >>>>>> >>>>>> >>>>>> -Jack >>>>>> >>>>>> >>>>>> >>>>>> On Sun, Dec 10, 2023 at 10:27 AM Ryan Blue <b...@tabular.io> wrote: >>>>>> >>>>>> Rahil, thanks for working on this. It has some really good ideas that >>>>>> we hadn't considered before like a way for the service to plan how to >>>>>> break >>>>>> up the work of scan planning. I really like that idea because it makes it >>>>>> much easier for the service to keep memory consumption low across >>>>>> requests. >>>>>> >>>>>> >>>>>> >>>>>> My primary feedback is that I think it's a little too complicated >>>>>> (with both sharding and pagination) and could be modified slightly so >>>>>> that >>>>>> the service doesn't need to be stateful. If the service isn't necessarily >>>>>> stateful then it should be easier to build implementations. >>>>>> >>>>>> >>>>>> >>>>>> To make it possible for the service to be stateless, I'm proposing >>>>>> that rather than creating shard IDs that are tracked by the service, the >>>>>> information for a shard can be sent to the client. My assumption here is >>>>>> that most implementations would create shards by reading the manifest >>>>>> list, >>>>>> filtering on partition ranges, and creating a shard for some reasonable >>>>>> size of manifest content. For example, if a table has 100MB of metadata >>>>>> in >>>>>> 25 manifests that are about 4 MB each, then it might create 9 shards with >>>>>> 1-4 manifests each. The service could send those shards to the client as >>>>>> a >>>>>> list of manifests to read and the client could send the shard information >>>>>> back to the service to get the data files in each shard (along with the >>>>>> original filter). >>>>>> >>>>>> >>>>>> >>>>>> There's a slight trade-off that the protocol needs to define how to >>>>>> break the work into shards. I'm interested in hearing if that would work >>>>>> with how you were planning on building the service on your end. Another >>>>>> option is to let the service send back arbitrary JSON that would get >>>>>> returned for each shard. Either way, I like that this would make it so >>>>>> the >>>>>> service doesn't need to persist anything. We could also make it so that >>>>>> small tables don't require multiple requests. For example, a client could >>>>>> call the route to get file tasks with just a filter. >>>>>> >>>>>> >>>>>> >>>>>> What do you think? >>>>>> >>>>>> >>>>>> >>>>>> Ryan >>>>>> >>>>>> >>>>>> >>>>>> On Fri, Dec 8, 2023 at 10:41 AM Chertara, Rahil >>>>>> <rcher...@amazon.com.invalid> wrote: >>>>>> >>>>>> Hi all, >>>>>> >>>>>> My name is Rahil Chertara, and I’m a part of the Iceberg team at >>>>>> Amazon EMR and Athena. I’m reaching out to share a proposal for a new >>>>>> Scan >>>>>> API that will be utilized by the RESTCatalog. The process for table scan >>>>>> planning is currently done within client engines such as Apache Spark. By >>>>>> moving scan functionality to the RESTCatalog, we can integrate Iceberg >>>>>> table scans with external services, which can lead to several benefits. >>>>>> >>>>>> For example, we can leverage caching and indexes on the server side >>>>>> to improve planning performance. Furthermore, by moving this scan logic >>>>>> to >>>>>> the RESTCatalog, non-JVM engines can integrate more easily. This all can >>>>>> be >>>>>> found in the detailed proposal below. Feel free to comment, and add your >>>>>> suggestions . >>>>>> >>>>>> Detailed proposal: >>>>>> https://docs.google.com/document/d/1FdjCnFZM1fNtgyb9-v9fU4FwOX4An-pqEwSaJe8RgUg/edit#heading=h.cftjlkb2wh4h >>>>>> >>>>>> Github POC: https://github.com/apache/iceberg/pull/9252 >>>>>> >>>>>> Regards, >>>>>> >>>>>> Rahil Chertara >>>>>> Amazon EMR & Athena >>>>>> rcher...@amazon.com >>>>>> >>>>>> >>>>>> >>>>>> >>>>>> >>>>>> >>>>>> -- >>>>>> >>>>>> Ryan Blue >>>>>> >>>>>> Tabular >>>>>> >>>>>> >>>>>> >>>>>> >>>>>> -- >>>>>> >>>>>> Ryan Blue >>>>>> >>>>>> Tabular >>>>>> >>>>>> >>>>>> >>>>>> >>>>>> -- >>>>>> >>>>>> Ryan Blue >>>>>> >>>>>> Tabular >>>>>> >>>>>> >>>>>> >>>>>> >>>>>> -- >>>>>> >>>>>> Ryan Blue >>>>>> >>>>>> Tabular >>>>>> >>>>>> >>>>>> >>>>>> >>>>>> -- >>>>>> >>>>>> Ryan Blue >>>>>> >>>>>> Tabular >>>>>> >>>>>> >>>>> >>>>> -- >>>>> Ryan Blue >>>>> Tabular >>>>> >>>> > > -- > Ryan Blue > Tabular >