We merged the spec change for content file in
https://github.com/apache/iceberg/pull/9717, the next step is to merge the
PlanTable and PreplanTable API spec change in
https://github.com/apache/iceberg/pull/9695. I guess people were a bit busy
in the past few weeks due to the Iceberg summit, you should see more
progress pretty soon!
Best,
Jack Ye
On Sat, May 18, 2024 at 4:05 PM Pucheng Yang <py...@pinterest.com.invalid>
wrote:
> Hi all, I wonder if we have a ETA for this change? thanks
>
> On Wed, Jan 31, 2024 at 10:30 AM Chertara, Rahil
> <rcher...@amazon.com.invalid> wrote:
>
>> Sure, I can look into adding this to the spec.
>> Thanks to everyone for sharing their thoughts, appreciate it!
>>
>>
>>
>> *From: *Ryan Blue <b...@tabular.io>
>> *Reply-To: *"dev@iceberg.apache.org" <dev@iceberg.apache.org>
>> *Date: *Wednesday, January 31, 2024 at 10:22 AM
>> *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.
>>
>>
>>
>> Looks good to me! Should we get a PR up to add it to the OpenAPI spec?
>>
>>
>>
>> On Wed, Jan 31, 2024 at 10:16 AM Jack Ye <yezhao...@gmail.com> wrote:
>>
>> 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
>>
>>
>>
>>
>> --
>>
>> Ryan Blue
>>
>> Tabular
>>
>
