On Mon, Feb 27, 2023 at 3:47 PM SiNan Liu <liusinan1...@gmail.com> wrote:
> > > > I read it and they look identical. What's the difference between them? > > Current avro,json, and protobuf schemas are all implemented based on AVRO. > > What do you mean, they are all implemented based on Avro? You mean the > > protobuf schema is converted into an Avro Schema, and then you use Avro > > compatibility validation? > > > `org.apache.pulsar.broker.service.schema.ProtobufSchemaCompatibilityCheck` > `org.apache.pulsar.broker.service.schema.AvroSchemaCompatibilityCheck` > `org.apache.pulsar.broker.service.schema.JsonSchemaCompatibilityCheck` > They all extends `AvroSchemaBasedCompatibilityCheck`, the > `checkCompatible()` is the same implementation with `AVRO`. > Can you please explain how a Protobuf Schema descriptor can be validated for backward compatibility check using Avro based compatibility rules? Doesn't it expect the schema to be Avro, but it is actually a Protobuf descriptor? Is there some translation happening? > > > I think you should structure the validation rules differently: > > > The Compatibility check strategy is described on the website > > https://pulsar.apache.org/docs/next/schema-understand/#schema-compatibility-check-strategy > 1. BACKWARD(CanReadExistingStrategy): Consumers using schema V3 can process > data written by producers using the last schema version V2. So V2 is > "writtenSchema" and V3 is "readSchema". > 2. FORWARD(CanBeReadByExistingStrategy): Consumers using the last schema > version V2 can process data written by producers using a new schema V3, > even though they may not be able to use the full capabilities of the new > schema. So V3 is "writtenSchema" and V2 is "readSchema". > 3. FULL(CanBeReadMutualStrategy): Schemas are both backward and forward > compatible. > Schema can evolve. The old version schema and the new version schema should > be well understood. > > I'm sorry - I don't understand. I understand the different compatibility check strategies. If you just spell them out here, then as you say, just translate the Protobuf Descriptor into an Avro schema and run the Avro compatibility validation, no? I believe the answer is no, since you may want to verify different things when it comes to Protobuf, which are different then Avro. At the current state, I can't understand your design at all. Please help clarify that. > > So each strategy should have its own section. > > > The arguments of `canRead()` are writtenSchema and readSchema. As we've > just described, we only need to change the order of arguments we pass to > `canRead()`. > > > > Thanks, > sinan > > > Asaf Mesika <asaf.mes...@gmail.com> 于2023年2月27日周一 20:49写道： > > > > > > > And you can see the difference between ProtoBuf and ProtoBufNative: > > > > > > https://pulsar.apache.org/docs/next/schema-get-started/#protobufnative > > > > > > https://pulsar.apache.org/docs/next/schema-get-started/#protobuf > > > > > I read it and they look identical. What's the difference between them? > > > > Current avro,json, and protobuf schemas are all implemented based on > AVRO. > > > > What do you mean, they are all implemented based on Avro? You mean the > > protobuf schema is converted into an Avro Schema, and then you use Avro > > compatibility validation? > > > > > > > *Here are the basic compatibility rules we've defined:* > > > > > > I think you should structure the validation rules differently: > > > > * Backward checks > > ** List down rules, where use newSchema (the schema used by producer or > > consumer) and existingSchema (last schema used) > > * Forward > > ** List down rules, where use newSchema (the schema used by producer or > > consumer) and existingSchema (last schema used) > > > > So each strategy should have its own section. > > > > I'm saying this since you used "writttenSchema" word but it represents > > something completely different if it's backward or forward check. > > > > Once you'll have that structure like that, I personally will be able to > > read and understand it. > > > > > > The motivation and problem statement are now good - thanks for improving > > it. > > > > On Mon, Feb 27, 2023 at 8:20 AM SiNan Liu <liusinan1...@gmail.com> > wrote: > > > > > Hi! I updated the PIP issue again. This time I've added some background > > and > > > some explanations. > > > > > > The compatibility check rules are already written in the > Implementation. > > > ProtoBufNative implements the same canRead method as Apache Avro. > > > It does this by checking whether the schema for writing and reading is > > > compatible. I also indicate whether the writtenSchema and readSchema of > > the > > > Backward, Forward, and Full strategies are the old or the new version > of > > > the schema. > > > > > > Thanks, > > > sinan > > > > > > Asaf Mesika <asaf.mes...@gmail.com> 于2023年2月26日周日 23:24写道： > > > > > > > I'm sorry, but this PIP lacks a lot of background knowledge, so you > > need > > > to > > > > add IMO for people to understand it. You don't need to explain the > > entire > > > > pulsar in this PIP, but at the very least a few paragraphs detailing > > all > > > > you need to know, to put you in context: > > > > > > > > > > > > - Start by saying Pulsar as a built-in schema registry inside > Pulsar > > > > broker. > > > > - Every time the client updates the schema, it uploads it to > the > > > > broker. When that happens, it has a feature which validates if > > the > > > > new > > > > schema version is compatible with the previous versions. There > > > > are 4 types > > > > of compatibility: Full, ... (complete and explain each one > > briefly) > > > > - Also explain Pulsar Schema registry supports various schema > > > > protocols: Avro, protobuf native, ... (complete the rest), each > > > > protocol > > > > has a schema which dictates how to serialize and deserialize the > > > message > > > > content into typed object. > > > > - Explain in short what is protobuf native (compare protobuf > > > non-native) > > > > - Please don't paste code instead of explaining. > > > > - Explain that protobuf native current validation check is only > > > > composed of checking the root message name is the same between > > > > the current > > > > schema version and the new version. > > > > - Explain briefly what is a root message and its name. > > > > - Explain the problem (list scenarios) that we have because > > > protobuf > > > > native schema only supports FULL compatibility validation. > > > > > > > > > > > > Regarding high level design - as in what you plan to do. > > > > I suggest you add "High Level Design" and in it detail how you plan > to > > > > validate, per protobuf version, per compatibility check (backward, > > > forward, > > > > full,...). > > > > I tried reading the implementation - for me , it's all over the > place. > > > Can > > > > you please list in order what I wrote above, and list the validation > > > rules > > > > with a good explanation why you validate it like that? > > > > > > > > Lastly, one you have all the validation rules clearly stated, you can > > use > > > > it to document it properly so users can know what validation to > expect. > > > > > > > > Thanks, > > > > > > > > Asaf > > > > > > > > > > > > On Wed, Feb 22, 2023 at 5:10 PM SiNan Liu <liusinan1...@gmail.com> > > > wrote: > > > > > > > > > Sorry, my mistake. I removed the code and described the design to > > > improve > > > > > the PROTOBUF_NATIVE schema compatibility checks. You can have a > look. > > > 😊 > > > > > > > > > > Asaf Mesika <asaf.mes...@gmail.com> 于2023年2月22日周三 21:16写道： > > > > > > > > > > > I read it but you're almost directly diving into the code - it > will > > > > take > > > > > me > > > > > > hours just to reverse engineer your design. > > > > > > > > > > > > Can you please include a "High Level Design" section in which you > > > > explain > > > > > > how you plan to tackle any issue? > > > > > > If I can read that section and explain to someone else how this > > will > > > > > work, > > > > > > it means the section is complete. > > > > > > > > > > > > Let's leave the code to the PRs. > > > > > > > > > > > > > > > > > > On Sun, Feb 19, 2023 at 2:59 PM SiNan Liu < > liusinan1...@gmail.com> > > > > > wrote: > > > > > > > > > > > > > Hi all, > > > > > > > > > > > > > > I made a PIP to discuss: > > > > https://github.com/apache/pulsar/issues/19565 > > > > > . > > > > > > > > > > > > > > We can talk about the current design here. Especially for the > > field > > > > > type > > > > > > > change check rules, please give your valuable advice. > > > > > > > > > > > > > > Thanks, > > > > > > > Sinan > > > > > > > > > > > > > > > > > > > > > > > > > > > >
