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From Andrey Mashenkov <andrey.mashen...@gmail.com>
Subject Re: IEP-54: Schema-first approach for 3.0
Date Tue, 24 Nov 2020 09:27:55 GMT
Denis,

Good point. Both serializers use reflection API.
However, we will allow users to configure static schema along with 'strict'
schema mode, we still need to validate user classes on client nodes against
the latest schema in the grid  and reflection API is the only way to do it.
One can find a few articles on the internet on how to enable reflection in
GraalVM.

I'll create a task for supporting GraalVM, and maybe someone who is
familiar with GraalVM will suggest a solution or a proper workaround. Or
I'll do it a bit later.
If no workaround is found, we could allow users to write it's own
serializer, but I don't think it is a good idea to expose any internal
classes to the public.

On Tue, Nov 24, 2020 at 2:55 AM Denis Magda <dmagda@apache.org> wrote:

> Andrey, thanks for the update,
>
> Does any of the serializers take into consideration the
> native-image-generation feature of GraalVM?
> https://www.graalvm.org/reference-manual/native-image/
>
> With the current binary marshaller, we can't even generate a native image
> for the code using our thin client APIs.
>
> -
> Denis
>
>
> On Mon, Nov 23, 2020 at 4:39 AM Andrey Mashenkov <
> andrey.mashenkov@gmail.com>
> wrote:
>
> > Hi Igniters,
> >
> > I'd like to continue discussion of IEP-54 (Schema-first approach).
> >
> > Hope everyone who is interested had a chance to get familiar with the
> > proposal [1].
> > Please, do not hesitate to ask questions and share your ideas.
> >
> > I've prepared a prototype of serializer [2] for the data layout described
> > in the proposal.
> > In prototy, I compared 2 approaches to (de)serialize objects, the first
> one
> > uses java reflection/unsafe API and similar to one we already use in
> Ignite
> > and the second one generates serializer for particular user class and
> uses
> > Janino library for compilation.
> > Second one shows better results in benchmarks.
> > I think we can go with it as default serializer and have reflection-based
> > implementation as a fallback if someone will have issues with the first
> > one.
> > WDYT?
> >
> > There are a number of tasks under the umbrella ticket [3] waiting for the
> > assignee.
> >
> > BTW, I'm going to create more tickets for schema manager modes
> > implementation, but would like to clarify some details.
> >
> > I thought schemaManager on each node should held:
> >   1. Local mapping of "schema version" <--> validated local key/value
> > classes pair.
> >   2. Cluster-wide schema changes history.
> > On the client side. Before any key-value API operation we should
> validate a
> > schema for a given key-value pair.
> > If there is no local-mapping exists for a given key-value pair or if a
> > cluster wide schema has a more recent version then the key-value pair
> > should be validated against the latest version and local mapping should
> be
> > updated/actualized.
> > If an object doesn't fit to the latest schema then it depends on schema
> > mode: either fail the operation ('strict' mode) or a new mapping should
> be
> > created and a new schema version should be propagated to the cluster.
> >
> > On the server side we usually have no key-value classes and we operate
> with
> > tuples.
> > As schema change history is available and a tuple has schema version,
> then
> > it is possible to upgrade any received tuple to the last version without
> > desialization.
> > Thus we could allow nodes to send key-value pairs of previous versions
> (if
> > they didn't receive a schema update yet) without reverting schema changes
> > made by a node with newer classes.
> >
> > Alex, Val, Ivan did you mean the same?
> >
> >
> > [1]
> >
> >
> https://cwiki.apache.org/confluence/display/IGNITE/IEP-54%3A+Schema-first+Approach
> > [2] https://github.com/apache/ignite/tree/ignite-13618/modules/commons
> > [3] https://issues.apache.org/jira/browse/IGNITE-13616
> >
> > On Thu, Sep 17, 2020 at 9:21 AM Ivan Pavlukhin <vololo100@gmail.com>
> > wrote:
> >
> > > Folks,
> > >
> > > Please do not ignore history. We had a thread [1] with many bright
> > > ideas. We can resume it.
> > >
> > > [1]
> > >
> >
> http://apache-ignite-developers.2346864.n4.nabble.com/Applicability-of-term-cache-to-Apache-Ignite-td36541.html
> > >
> > > 2020-09-10 0:08 GMT+03:00, Denis Magda <dmagda@apache.org>:
> > > > Val, makes sense, thanks for explaining.
> > > >
> > > > Agree that we need to have a separate discussion thread for the
> "table"
> > > and
> > > > "cache" terms substitution. I'll appreciate it if you start the
> thread
> > > > sharing pointers to any relevant IEPs and reasoning behind the
> > suggested
> > > > change.
> > > >
> > > > -
> > > > Denis
> > > >
> > > >
> > > > On Tue, Sep 8, 2020 at 6:01 PM Valentin Kulichenko <
> > > > valentin.kulichenko@gmail.com> wrote:
> > > >
> > > >> Hi Denis,
> > > >>
> > > >> I guess the wording in the IEP is a little bit confusing. All it
> means
> > > is
> > > >> that you should not create nested POJOs, but rather inline fields
> > into a
> > > >> single POJO that is mapped to a particular schema. In other words,
> > > nested
> > > >> POJOs are not supported.
> > > >>
> > > >> Alex, is this correct? Please let me know if I'm missing something.
> > > >>
> > > >> As for the "cache" term, I agree that it is outdated, but I'm not
> sure
> > > >> what we can replace it with. "Table" is tightly associated with SQL,
> > but
> > > >> SQL is optional in our case. Do you want to create a separate
> > discussion
> > > >> about this?
> > > >>
> > > >> -Val
> > > >>
> > > >> On Tue, Sep 8, 2020 at 4:37 PM Denis Magda <dmagda@apache.org>
> wrote:
> > > >>
> > > >>> Val,
> > > >>>
> > > >>> I've checked the IEP again and have a few questions.
> > > >>>
> > > >>> Arbitrary nested objects and collections are not allowed as column
> > > >>> values.
> > > >>> > Nested POJOs should either be inlined into schema, or stored
as
> > BLOBs
> > > >>>
> > > >>>
> > > >>> Could you provide a DDL code snippet showing how the inlining
of
> > POJOs
> > > >>> is
> > > >>> supposed to work?
> > > >>>
> > > >>> Also, we keep using the terms "cache" and "table" throughout the
> IEP.
> > > Is
> > > >>> it
> > > >>> the right time to discuss an alternate name that would replace
> those
> > > >>> too?
> > > >>> Personally, the "table" should stay and the "cache" should go
> > > >>> considering
> > > >>> that SQL is one of the primary APIs in Ignite and that DDL is
> > supported
> > > >>> out-of-the-box.
> > > >>>
> > > >>>
> > > >>> -
> > > >>> Denis
> > > >>>
> > > >>>
> > > >>> On Mon, Sep 7, 2020 at 12:26 PM Valentin Kulichenko <
> > > >>> valentin.kulichenko@gmail.com> wrote:
> > > >>>
> > > >>> > Ivan,
> > > >>> >
> > > >>> > I see your point. I agree that with the automatic updates
we step
> > > into
> > > >>> the
> > > >>> > schema-last territory.
> > > >>> >
> > > >>> > Actually, if we support automatic evolution, we can as well
> support
> > > >>> > creating a cache without schema and inferring it from the
first
> > > >>> > insert.
> > > >>> In
> > > >>> > other words, we can have both "schema-first" and "schema-last"
> > modes.
> > > >>> >
> > > >>> > Alexey, what do you think?
> > > >>> >
> > > >>> > -Val
> > > >>> >
> > > >>> > On Mon, Sep 7, 2020 at 5:59 AM Alexey Goncharuk <
> > > >>> > alexey.goncharuk@gmail.com>
> > > >>> > wrote:
> > > >>> >
> > > >>> > > Ivan,
> > > >>> > >
> > > >>> > > Thank you, I got your concern now. As it is mostly regarding
> the
> > > >>> > > terminology, I am absolutely fine with changing the
name to
> > > whatever
> > > >>> fits
> > > >>> > > the approach best. Dynamic or evolving schema sounds
great. I
> > will
> > > >>> make
> > > >>> > > corresponding changes to the IEP once we settle on the
name.
> > > >>> > >
> > > >>> > > пн, 7 сент. 2020 г. в 11:33, Ivan Pavlukhin
<
> vololo100@gmail.com
> > >:
> > > >>> > >
> > > >>> > > > Hi Val,
> > > >>> > > >
> > > >>> > > > Thank you for your answer!
> > > >>> > > >
> > > >>> > > > My understanding is a little bit different. Yes,
schema
> > evolution
> > > >>> > > > definitely should be possible. But I see a main
difference in
> > > "how
> > > >>> > > > schema is updated". I treat a common SQL approach
> schema-first.
> > > >>> Schema
> > > >>> > > > and data manipulation operations are clearly separated
and it
> > > >>> enables
> > > >>> > > > interesting capabilities, e.g. preventing untended
schema
> > changes
> > > >>> > > > by
> > > >>> > > > mistaken data operations, restricting user permissions
to
> > change
> > > >>> > > > schema.
> > > >>> > > >
> > > >>> > > > > Schema-first means that schema exists in advance
and all
> the
> > > >>> stored
> > > >>> > > data
> > > >>> > > > is compliant with it - that's exactly what is proposed.
> > > >>> > > >
> > > >>> > > > A schema-last approach mentioned in [1] also assumes
that
> > schema
> > > >>> > > > exists, but it is inferred from data. Is not it
more similar
> to
> > > >>> > > > the
> > > >>> > > > proposing approach?
> > > >>> > > >
> > > >>> > > > And I would like to say, that my main concern so
far is
> mostly
> > > >>> > > > about
> > > >>> > > > terminology. And I suppose if it confuses me then
others
> might
> > be
> > > >>> > > > confused as well. My feeling is closer to "dynamic
or liquid
> or
> > > >>> > > > may
> > > >>> be
> > > >>> > > > evolving schema".
> > > >>> > > >
> > > >>> > > > [1]
> > > >>> > > >
> > > >>> >
> > >
> https://people.cs.umass.edu/~yanlei/courses/CS691LL-f06/papers/SH05.pdf
> > > >>> > > >
> > > >>> > > > 2020-09-07 0:47 GMT+03:00, Valentin Kulichenko
<
> > > >>> > > > valentin.kulichenko@gmail.com>:
> > > >>> > > > > Hi Ivan,
> > > >>> > > > >
> > > >>> > > > > I don't see an issue with that. Schema-first
means that
> > schema
> > > >>> exists
> > > >>> > > in
> > > >>> > > > > advance and all the stored data is compliant
with it -
> that's
> > > >>> exactly
> > > >>> > > > what
> > > >>> > > > > is proposed. There are no restrictions prohibiting
changes
> to
> > > >>> > > > > the
> > > >>> > > schema.
> > > >>> > > > >
> > > >>> > > > > -Val
> > > >>> > > > >
> > > >>> > > > > On Sat, Sep 5, 2020 at 9:52 PM Ivan Pavlukhin
<
> > > >>> vololo100@gmail.com>
> > > >>> > > > wrote:
> > > >>> > > > >
> > > >>> > > > >> Alexey,
> > > >>> > > > >>
> > > >>> > > > >> I am a little bit confused with terminology.
My
> > understanding
> > > >>> > conforms
> > > >>> > > > >> to a survey [1] (see part X Semi Structured
Data). Can we
> > > >>> > > > >> really
> > > >>> > treat
> > > >>> > > > >> a "dynamic schema" approach as a kind
of "schema-first"?
> > > >>> > > > >>
> > > >>> > > > >> [1]
> > > >>> > > > >>
> > > >>> > >
> > > >>>
> > >
> https://people.cs.umass.edu/~yanlei/courses/CS691LL-f06/papers/SH05.pdf
> > > >>> > > > >>
> > > >>> > > > >> 2020-09-02 1:53 GMT+03:00, Denis Magda
<dmagda@apache.org
> >:
> > > >>> > > > >> >>
> > > >>> > > > >> >> However, could you please elaborate
on the relation
> > between
> > > >>> > Ignite
> > > >>> > > > and
> > > >>> > > > >> >> ORM?
> > > >>> > > > >> >> Is there a use case for Hibernate
running on top of
> > Ignite
> > > >>> > > > >> >> (I
> > > >>> > > haven't
> > > >>> > > > >> >> seen
> > > >>> > > > >> >> one so far)? If so, what is missing
exactly on the
> Ignite
> > > >>> side to
> > > >>> > > > >> support
> > > >>> > > > >> >> this? In my understanding, all
you need is SQL API
> which
> > we
> > > >>> > already
> > > >>> > > > >> have.
> > > >>> > > > >> >> Am I missing something?
> > > >>> > > > >> >
> > > >>> > > > >> >
> > > >>> > > > >> > Good point, yes, if all the ORM integrations
use Ignite
> > SQL
> > > >>> APIs
> > > >>> > > > >> > internally, then they can easily
translate an Entity
> > object
> > > >>> into
> > > >>> > an
> > > >>> > > > >> > INSERT/UPDATE statement that lists
all the object's
> > fields.
> > > >>> > Luckily,
> > > >>> > > > >> > our
> > > >>> > > > >> > Spring Data integration is already
based on the Ignite
> SQL
> > > >>> > > > >> > APIs
> > > >>> > and
> > > >>> > > > >> > needs
> > > >>> > > > >> > to be improved once the schema-first
approach is
> > supported.
> > > >>> That
> > > >>> > > would
> > > >>> > > > >> > solve a ton of usability issues.
> > > >>> > > > >> >
> > > >>> > > > >> > I would revise the Hibernate integration
as well during
> > the
> > > >>> Ignite
> > > >>> > > 3.0
> > > >>> > > > >> dev
> > > >>> > > > >> > phase. Can't say if it's used a lot
but Spring Data is
> > > >>> > > > >> > getting
> > > >>> > > > traction
> > > >>> > > > >> for
> > > >>> > > > >> > sure.
> > > >>> > > > >> >
> > > >>> > > > >> > @Michael Pollind, I'll loop you in
as long as you've
> > started
> > > >>> > working
> > > >>> > > > on
> > > >>> > > > >> the
> > > >>> > > > >> > Ignite support for Micornaut Data
> > > >>> > > > >> > <
> > > >>> >
> https://micronaut-projects.github.io/micronaut-data/latest/guide/>
> > > >>> > > > and
> > > >>> > > > >> > came across some challenges. Just
watch this discussion.
> > > >>> > > > >> > That's
> > > >>> > what
> > > >>> > > > is
> > > >>> > > > >> > coming in Ignite 3.0.
> > > >>> > > > >> >
> > > >>> > > > >> >
> > > >>> > > > >> > -
> > > >>> > > > >> > Denis
> > > >>> > > > >> >
> > > >>> > > > >> >
> > > >>> > > > >> > On Mon, Aug 31, 2020 at 5:11 PM Valentin
Kulichenko <
> > > >>> > > > >> > valentin.kulichenko@gmail.com>
wrote:
> > > >>> > > > >> >
> > > >>> > > > >> >> Hi Denis,
> > > >>> > > > >> >>
> > > >>> > > > >> >> Generally speaking, I believe
that the schema-first
> > > approach
> > > >>> > > natively
> > > >>> > > > >> >> addresses the issue if duplicate
fields in key and
> value
> > > >>> objects,
> > > >>> > > > >> because
> > > >>> > > > >> >> schema will be created for a
cache, not for an object,
> as
> > > it
> > > >>> > > happens
> > > >>> > > > >> now.
> > > >>> > > > >> >> Basically, the schema will define
whether there is a
> > > primary
> > > >>> key
> > > >>> > or
> > > >>> > > > >> >> not,
> > > >>> > > > >> >> and which fields are included
in case there is one. Any
> > API
> > > >>> that
> > > >>> > we
> > > >>> > > > >> would
> > > >>> > > > >> >> have must be compliant with this,
so it becomes fairly
> > easy
> > > >>> > > > >> >> to
> > > >>> > work
> > > >>> > > > >> >> with
> > > >>> > > > >> >> data as with a set of records,
rather than key-value
> > pairs.
> > > >>> > > > >> >>
> > > >>> > > > >> >> However, could you please elaborate
on the relation
> > between
> > > >>> > Ignite
> > > >>> > > > and
> > > >>> > > > >> >> ORM?
> > > >>> > > > >> >> Is there a use case for Hibernate
running on top of
> > Ignite
> > > >>> > > > >> >> (I
> > > >>> > > haven't
> > > >>> > > > >> >> seen
> > > >>> > > > >> >> one so far)? If so, what is missing
exactly on the
> Ignite
> > > >>> side to
> > > >>> > > > >> support
> > > >>> > > > >> >> this? In my understanding, all
you need is SQL API
> which
> > we
> > > >>> > already
> > > >>> > > > >> have.
> > > >>> > > > >> >> Am I missing something?
> > > >>> > > > >> >>
> > > >>> > > > >> >> -Val
> > > >>> > > > >> >>
> > > >>> > > > >> >> On Mon, Aug 31, 2020 at 2:08
PM Denis Magda <
> > > >>> dmagda@apache.org>
> > > >>> > > > wrote:
> > > >>> > > > >> >>
> > > >>> > > > >> >> > Val,
> > > >>> > > > >> >> >
> > > >>> > > > >> >> > I would propose adding another
point to the
> motivations
> > > >>> > > > >> >> > list
> > > >>> > > which
> > > >>> > > > >> >> > is
> > > >>> > > > >> >> > related to the ORM frameworks
such as Spring Data,
> > > >>> Hibernate,
> > > >>> > > > >> Micronaut
> > > >>> > > > >> >> and
> > > >>> > > > >> >> > many others.
> > > >>> > > > >> >> >
> > > >>> > > > >> >> > Presently, the storage engine
requires to distinguish
> > key
> > > >>> > objects
> > > >>> > > > >> >> > from
> > > >>> > > > >> >> the
> > > >>> > > > >> >> > value ones that complicate
the usage of Ignite with
> > those
> > > >>> ORM
> > > >>> > > > >> >> > frameworks
> > > >>> > > > >> >> > (especially if a key object
comprises several
> fields).
> > > >>> > > > >> >> > More
> > > >>> on
> > > >>> > > this
> > > >>> > > > >> can
> > > >>> > > > >> >> be
> > > >>> > > > >> >> > found here:
> > > >>> > > > >> >> >
> > > >>> > > > >> >> >
> > > >>> > > > >> >>
> > > >>> > > > >>
> > > >>> > > >
> > > >>> > >
> > > >>> >
> > > >>>
> > >
> >
> http://apache-ignite-developers.2346864.n4.nabble.com/DISCUSSION-Key-and-Value-fields-with-same-name-and-SQL-DML-td47557.html
> > > >>> > > > >> >> >
> > > >>> > > > >> >> > It will be nice if the new
schema-first approach
> allows
> > > us
> > > >>> to
> > > >>> > > work
> > > >>> > > > >> with
> > > >>> > > > >> >> > a
> > > >>> > > > >> >> > single entity object when
it comes to the ORMs. With
> no
> > > >>> need to
> > > >>> > > > >> >> > split
> > > >>> > > > >> >> > the
> > > >>> > > > >> >> > entity into a key and value.
Just want to be sure
> that
> > > the
> > > >>> > Ignite
> > > >>> > > > >> >> > 3.0
> > > >>> > > > >> >> > has
> > > >>> > > > >> >> > all the essential public
APIs that would support the
> > > >>> > > single-entity
> > > >>> > > > >> >> > based
> > > >>> > > > >> >> > approach.
> > > >>> > > > >> >> >
> > > >>> > > > >> >> > What do you think?
> > > >>> > > > >> >> >
> > > >>> > > > >> >> > -
> > > >>> > > > >> >> > Denis
> > > >>> > > > >> >> >
> > > >>> > > > >> >> >
> > > >>> > > > >> >> > On Fri, Aug 28, 2020 at
3:50 PM Valentin Kulichenko <
> > > >>> > > > >> >> > valentin.kulichenko@gmail.com>
wrote:
> > > >>> > > > >> >> >
> > > >>> > > > >> >> > > Igniters,
> > > >>> > > > >> >> > >
> > > >>> > > > >> >> > > One of the big changes
proposed for Ignite 3.0 is
> the
> > > >>> > so-called
> > > >>> > > > >> >> > > "schema-first approach".
To add more clarity, I've
> > > >>> > > > >> >> > > started
> > > >>> > > > writing
> > > >>> > > > >> >> > > the
> > > >>> > > > >> >> > IEP
> > > >>> > > > >> >> > > for this change:
> > > >>> > > > >> >> > >
> > > >>> > > > >> >> > >
> > > >>> > > > >> >> >
> > > >>> > > > >> >>
> > > >>> > > > >>
> > > >>> > > >
> > > >>> > >
> > > >>> >
> > > >>>
> > >
> >
> https://cwiki.apache.org/confluence/display/IGNITE/IEP-54%3A+Schema-first+Approach
> > > >>> > > > >> >> > >
> > > >>> > > > >> >> > > Please take a look
and let me know if there are any
> > > >>> immediate
> > > >>> > > > >> >> > > thoughts,
> > > >>> > > > >> >> > > suggestions, or objections.
> > > >>> > > > >> >> > >
> > > >>> > > > >> >> > > -Val
> > > >>> > > > >> >> > >
> > > >>> > > > >> >> >
> > > >>> > > > >> >>
> > > >>> > > > >> >
> > > >>> > > > >>
> > > >>> > > > >>
> > > >>> > > > >> --
> > > >>> > > > >>
> > > >>> > > > >> Best regards,
> > > >>> > > > >> Ivan Pavlukhin
> > > >>> > > > >>
> > > >>> > > > >
> > > >>> > > >
> > > >>> > > >
> > > >>> > > > --
> > > >>> > > >
> > > >>> > > > Best regards,
> > > >>> > > > Ivan Pavlukhin
> > > >>> > > >
> > > >>> > >
> > > >>> >
> > > >>>
> > > >>
> > > >
> > >
> > >
> > > --
> > >
> > > Best regards,
> > > Ivan Pavlukhin
> > >
> >
> >
> > --
> > Best regards,
> > Andrey V. Mashenkov
> >
>


-- 
Best regards,
Andrey V. Mashenkov

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