A "List Type" sounds like a good direction to me.
The comment on the type system was a bit brief, I agree. The idea is
to see
if something like that can ease validation. Especially the correlation
system seems quite complex (proxies to work around order of
initialization).
For example, let's assume we don't think primarily about "java
types" but
would define types as one of the following (just examples, haven't
thought
all the details through):
(a) category type: implies string, and a fix set of possible values.
Those would be passes and naturally make it into the docs and
validation.
Maps to a String or Enum in Java.
(b) numeric integer type: implies long (or optionally integer, if
we want
to automatically check overflow / underflow). would take typical domain
validators, like non-negative, etc.
(c) numeric real type: same as above (double or float)
(d) numeric interval type: either defined as an interval, or
references
other parameter by key. validation by valid interval.
(e) quantity: a measure and a unit. separately parsable. The
measure's
type could be any of the numeric types above, with same validation
rules.
With a system like the above, would we still correlation validators?
Are
there still cases that we need to catch early (config loading) or
are the
remaining cases sufficiently rare and runtime or setup specific,
that it is
fine to handle them in component initialization?
On Sun, Aug 18, 2019 at 6:36 PM Dawid Wysakowicz
<dwysakow...@apache.org>
wrote:
Hi Stephan,
Thank you for your opinion.
Actually list/composite types are the topics we spent the most of the
time. I understand that from a perspective of a full blown type
system,
a field like isList may look weird. Please let me elaborate a bit more
on the reason behind it though. Maybe we weren't clear enough about it
in the FLIP. The key feature of all the conifg options is that they
must
have a string representation as they might come from a configuration
file. Moreover it must be a human readable format, so that the values
might be manually adjusted. Having that in mind we did not want to
add a
support of an arbitrary nesting and we decided to allow for lists only
(and flat objects - I think though in the current design there is a
mistake around the Configurable interface). I think though you have a
point here and it would be better to have a ListConfigOption
instead of
this field. Does it make sense to you?
As for the second part of your message. I am not sure if I understood
it. The validators work with parse/deserialized values from
Configuration that means they can be bound to the generic parameter of
Configuration. You can have a RangeValidator<? extends
Comparable/Number>. I don't think the type hierarchy in the
ConfigOption
has anything to do with the validation logic. Could you elaborate a
bit
more what did you mean?
Best,
Dawid
On 18/08/2019 16:42, Stephan Ewen wrote:
I like the idea of enhancing the configuration and to do early
validation.
I feel that some of the ideas in the FLIP seem a bit ad hoc,
though. For
example, having a boolean "isList" is a clear indication of not
having
thought through the type/category system.
Also, having a more clear category system makes validation simpler.
For example, I have seen systems distinguishing between numeric
parameters
(valid ranges), category parameters (set of possible values),
quantities
like duration and memory size (need measure and unit), which
results in
an
elegant system for validation.
On Fri, Aug 16, 2019 at 5:22 PM JingsongLee <lzljs3620...@aliyun.com
.invalid>
wrote:
+1 to this, thanks Timo and Dawid for the design.
This allows the currently cluttered configuration of various
modules to be unified.
This is also first step of one of the keys to making new unified
TableEnvironment available for production.
Previously, we did encounter complex configurations, such as
specifying the skewed values of column in DDL. The skew may
be a single field or a combination of multiple fields. So the
configuration is very troublesome. We used JSON string to
configure it.
Best,
Jingsong Lee
------------------------------------------------------------------
From:Jark Wu <imj...@gmail.com>
Send Time:2019年8月16日(星期五) 16:44
To:dev <dev@flink.apache.org>
Subject:Re: [DISCUSS] FLIP-54: Evolve ConfigOption and Configuration
Thanks for starting this design Timo and Dawid,
Improving ConfigOption has been hovering in my mind for a long time.
We have seen the benefit when developing blink configurations and
connector
properties in 1.9 release.
Thanks for bringing it up and make such a detailed design.
I will leave my thoughts and comments there.
Cheers,
Jark
On Fri, 16 Aug 2019 at 22:30, Zili Chen <wander4...@gmail.com>
wrote:
Hi Timo,
It looks interesting. Thanks for preparing this FLIP!
Client API enhancement benefit from this evolution which
hopefully provides a better view of configuration of Flink.
In client API enhancement, we likely make the deployment
of cluster and submission of job totally defined by configuration.
Will take a look at the document in days.
Best,
tison.
Timo Walther <twal...@apache.org> 于2019年8月16日周五
下午10:12写道：
Hi everyone,
Dawid and I are working on making parts of ExecutionConfig and
TableConfig configurable via config options. This is necessary
to make
all properties also available in SQL. Additionally, with the
new SQL
DDL
based on properties as well as more connectors and formats
coming up,
unified configuration becomes more important.
We need more features around string-based configuration in the
future,
which is why Dawid and I would like to propose FLIP-54 for
evolving
the
ConfigOption and Configuration classes:
https://docs.google.com/document/d/1IQ7nwXqmhCy900t2vQLEL3N2HIdMg-JO8vTzo1BtyKU/edit
In summary it adds:
- documented types and validation
- more common types such as memory size, duration, list
- simple non-nested object types
Looking forward to your feedback,
Timo
