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From Hyukjin Kwon <gurwls...@gmail.com>
Subject Re: Request to document the direct relationship between other configurations
Date Thu, 13 Feb 2020 00:47:47 GMT
Yes, that's probably our final goal to revisit the configurations to make
it structured and deduplicated documentation cleanly. +1.

One point I would like to add is though to add such information to the
documentation until we actually manage our final goal
since probably it's going to take a while to revisit/fix and make it fully
structured with the documentation.
If we go more conservatively, we can add such information to the new
configurations being added from now on at least, and keeping the existing
configurations as are.


On Thu, 13 Feb 2020, 06:12 Dongjoon Hyun, <dongjoon.hyun@gmail.com> wrote:

> Thank you for raising the issue, Hyukjin.
>
> According to the current status of discussion, it seems that we are able
> to agree on updating the non-structured configurations and keeping the
> structured configuration AS-IS.
>
> I'm +1 for the revisiting the configurations if that is our direction. If
> there is some mismatch in structured configurations, we may fix them
> together.
>
> Bests,
> Dongjoon.
>
> On Wed, Feb 12, 2020 at 8:08 AM Jules Damji <dmatrix@comcast.net> wrote:
>
>> All are valid and valuable observations to put into practice:
>>
>> * structured and meaningful config names
>> * explainable text or succinct description
>> * easily accessible or searchable
>>
>> While these are aspirational but gradually doable if we make it part of
>> the dev and review cycle. Often meaningful config names, like security,
>> come as after thought.
>>
>> At the AMA in Amsterdam Spark Summit last year, a few developers lamented
>> the lack of finding Spark configs—what they do; what they are used for;
>> when and why; and what are their default values.
>>
>> Though you one fetch them programmatically, one still has to know what
>> specific config one islooking for.
>>
>> Cheers
>> Jules
>>
>> Sent from my iPhone
>> Pardon the dumb thumb typos :)
>>
>> On Feb 12, 2020, at 5:19 AM, Hyukjin Kwon <gurwls223@gmail.com> wrote:
>>
>> 
>> Yeah, that's one of my point why I dont want to document this in the
>> guide yet.
>>
>> I would like to make sure dev people are on the same page that
>> documenting is a better practice. I dont intend to force as a hard
>> requirement; however, if that's pointed out, it should better to address.
>>
>>
>> On Wed, 12 Feb 2020, 21:30 Wenchen Fan, <cloud0fan@gmail.com> wrote:
>>
>>> In general I think it's better to have more detailed documents, but we
>>> don't have to force everyone to do it if the config name is structured. I
>>> would +1 to document the relationship of we can't tell it from the config
>>> names, e.g. spark.shuffle.service.enabled
>>> and spark.dynamicAllocation.enabled.
>>>
>>> On Wed, Feb 12, 2020 at 7:54 PM Hyukjin Kwon <gurwls223@gmail.com>
>>> wrote:
>>>
>>>> Also, I would like to hear other people' thoughts on here. Could I ask
>>>> what you guys think about this in general?
>>>>
>>>> 2020년 2월 12일 (수) 오후 12:02, Hyukjin Kwon <gurwls223@gmail.com>님이
작성:
>>>>
>>>>> To do that, we should explicitly document such structured
>>>>> configuration and implicit effect, which is currently missing.
>>>>> I would be more than happy if we document such implied relationship,
>>>>> *and* if we are very sure all configurations are structured correctly
>>>>> coherently.
>>>>> Until that point, I think it might be more practical to simply
>>>>> document it for now.
>>>>>
>>>>> > Btw, maybe off-topic, `spark.dynamicAllocation` is having another
>>>>> issue on practice - whether to duplicate description between configuration
>>>>> code and doc. I have been asked to add description on configuration code
>>>>> regardlessly, and existing codebase doesn't. This configuration is
>>>>> widely-used one.
>>>>> This is actually something we should fix too. in SQL configuration,
>>>>> now we don't have such duplications as of
>>>>> https://github.com/apache/spark/pull/27459 as it generates. We should
>>>>> do it in other configurations.
>>>>>
>>>>>
>>>>> 2020년 2월 12일 (수) 오전 11:47, Jungtaek Lim <kabhwan.opensource@gmail.com>님이
>>>>> 작성:
>>>>>
>>>>>> I'm looking into the case of `spark.dynamicAllocation` and this seems
>>>>>> to be the thing to support my voice.
>>>>>>
>>>>>>
>>>>>> https://github.com/apache/spark/blob/master/docs/configuration.md#dynamic-allocation
>>>>>>
>>>>>> I don't disagree with adding "This requires
>>>>>> spark.shuffle.service.enabled to be set." in the description of
>>>>>> `spark.dynamicAllocation.enabled`. This cannot be inferred implicitly,
>>>>>> hence it should be better to have it.
>>>>>>
>>>>>> Why I'm in favor of structured configuration & implicit effect
over
>>>>>> describing everything explicitly is there.
>>>>>>
>>>>>> 1. There're 10 configurations (if the doc doesn't miss any other
>>>>>> configuration) except `spark.dynamicAllocation.enabled`, and only
4
>>>>>> configurations are referred in the description of
>>>>>> `spark.dynamicAllocation.enabled` - majority of config keys are missing.
>>>>>> 2. I think it's intentional, but the table starts
>>>>>> with `spark.dynamicAllocation.enabled` which talks implicitly but
>>>>>> intuitively that if you disable this then everything on dynamic allocation
>>>>>> won't work. Missing majority of references on config keys don't get
it hard
>>>>>> to understand.
>>>>>> 3. Even `spark.dynamicAllocation` has bad case - see
>>>>>> `spark.dynamicAllocation.shuffleTracking.enabled` and
>>>>>> `spark.dynamicAllocation.shuffleTimeout`. It is not respecting the
>>>>>> structure of configuration. I think this is worse than not explicitly
>>>>>> mentioning the description. Let's assume the name has
>>>>>> been `spark.dynamicAllocation.shuffleTracking.timeout` - isn't it
intuitive
>>>>>> that setting `spark.dynamicAllocation.shuffleTracking.enabled` to
`false`
>>>>>> would effectively disable `spark.dynamicAllocation.shuffleTracking.timeout`?
>>>>>>
>>>>>> Btw, maybe off-topic, `spark.dynamicAllocation` is having another
>>>>>> issue on practice - whether to duplicate description between configuration
>>>>>> code and doc. I have been asked to add description on configuration
code
>>>>>> regardlessly, and existing codebase doesn't. This configuration is
>>>>>> widely-used one.
>>>>>>
>>>>>>
>>>>>> On Wed, Feb 12, 2020 at 11:22 AM Hyukjin Kwon <gurwls223@gmail.com>
>>>>>> wrote:
>>>>>>
>>>>>>> Sure, adding "[DISCUSS]" is a good practice to label it. I had
to do
>>>>>>> it although it might be "redundant" :-) since anyone can give
feedback to
>>>>>>> any thread in Spark dev mailing list, and discuss.
>>>>>>>
>>>>>>> This is actually more prevailing given my rough reading of
>>>>>>> configuration files. I would like to see this missing relationship
as a bad
>>>>>>> pattern, started from a personal preference.
>>>>>>>
>>>>>>> > Personally I'd rather not think someone won't understand
setting
>>>>>>> `.enabled` to `false` means the functionality is disabled and
effectively
>>>>>>> it disables all sub-configurations.
>>>>>>> > E.g. when `spark.sql.adaptive.enabled` is `false`, all the
>>>>>>> configurations for `spark.sql.adaptive.*` are implicitly no-op.
For me this
>>>>>>> is pretty intuitive and the one of major
>>>>>>> > benefits of the structured configurations.
>>>>>>>
>>>>>>> I don't think this is a good idea we assume for users to know
such
>>>>>>> contexts. One might think
>>>>>>> `spark.sql.adaptive.shuffle.fetchShuffleBlocksInBatch.enabled`
can
>>>>>>> partially enable the feature. It is better to be explicit to
>>>>>>> document since some of configurations are even difficult for
users to
>>>>>>> confirm if it is working or not.
>>>>>>> For instance, one might think setting
>>>>>>> 'spark.eventLog.rolling.maxFileSize' automatically enables rolling.
Then,
>>>>>>> they realise the log is not rolling later after the file
>>>>>>> size becomes bigger.
>>>>>>>
>>>>>>>
>>>>>>> 2020년 2월 12일 (수) 오전 10:47, Jungtaek Lim <
>>>>>>> kabhwan.opensource@gmail.com>님이 작성:
>>>>>>>
>>>>>>>> I'm sorry if I miss something, but this is ideally better
to be
>>>>>>>> started as [DISCUSS] as I haven't seen any reference to have
consensus on
>>>>>>>> this practice.
>>>>>>>>
>>>>>>>> For me it's just there're two different practices co-existing
on
>>>>>>>> the codebase, meaning it's closer to the preference of individual
(with
>>>>>>>> implicitly agreeing that others have different preferences),
or it hasn't
>>>>>>>> been discussed thoughtfully.
>>>>>>>>
>>>>>>>> Personally I'd rather not think someone won't understand
setting
>>>>>>>> `.enabled` to `false` means the functionality is disabled
and effectively
>>>>>>>> it disables all sub-configurations. E.g. when `spark.sql.adaptive.enabled`
>>>>>>>> is `false`, all the configurations for `spark.sql.adaptive.*`
are
>>>>>>>> implicitly no-op. For me this is pretty intuitive and the
one of major
>>>>>>>> benefits of the structured configurations.
>>>>>>>>
>>>>>>>> If we want to make it explicit, "all" sub-configurations
should
>>>>>>>> have redundant part of the doc. More redundant if the condition
is nested.
>>>>>>>> I agree this is the good step of "be kind" but less pragmatic.
>>>>>>>>
>>>>>>>> I'd be happy to follow the consensus we would make in this
thread.
>>>>>>>> Appreciate more voices.
>>>>>>>>
>>>>>>>> Thanks,
>>>>>>>> Jungtaek Lim (HeartSaVioR)
>>>>>>>>
>>>>>>>>
>>>>>>>> On Wed, Feb 12, 2020 at 10:36 AM Hyukjin Kwon <gurwls223@gmail.com>
>>>>>>>> wrote:
>>>>>>>>
>>>>>>>>> > I don't plan to document this officially yet
>>>>>>>>> Just to prevent confusion, I meant I don't yet plan to
document
>>>>>>>>> the fact that we should write the relationships in configurations
as a
>>>>>>>>> code/review guideline in
>>>>>>>>> https://spark.apache.org/contributing.html
>>>>>>>>>
>>>>>>>>>
>>>>>>>>> 2020년 2월 12일 (수) 오전 9:57, Hyukjin Kwon <gurwls223@gmail.com>님이
작성:
>>>>>>>>>
>>>>>>>>>> Hi all,
>>>>>>>>>>
>>>>>>>>>> I happened to review some PRs and I noticed that
some
>>>>>>>>>> configurations don't have some information
>>>>>>>>>> necessary.
>>>>>>>>>>
>>>>>>>>>> To be explicit, I would like to make sure we document
the direct
>>>>>>>>>> relationship between other configurations
>>>>>>>>>> in the documentation. For example,
>>>>>>>>>> `spark.sql.adaptive.shuffle.reducePostShufflePartitions.enabled`
>>>>>>>>>> can be only enabled when `spark.sql.adaptive.enabled`
is enabled.
>>>>>>>>>> That's clearly documented.
>>>>>>>>>> We're good in general given that we document them
in general in
>>>>>>>>>> Apache Spark.
>>>>>>>>>> See 'spark.task.reaper.enabled',
>>>>>>>>>> 'spark.dynamicAllocation.enabled', 'spark.sql.parquet.filterPushdown',
etc.
>>>>>>>>>>
>>>>>>>>>> However, I noticed such a pattern that such information
is
>>>>>>>>>> missing in some components in general, for example,
>>>>>>>>>> `spark.history.fs.cleaner.*`, `spark.history.kerberos.*`
and
>>>>>>>>>> `spark.history.ui.acls.* `
>>>>>>>>>>
>>>>>>>>>> I hope we all start to document such information.
Logically users
>>>>>>>>>> can't know the relationship and I myself
>>>>>>>>>> had to read the codes to confirm when I review.
>>>>>>>>>> I don't plan to document this officially yet because
to me it
>>>>>>>>>> looks a pretty logical request to me; however,
>>>>>>>>>> let me know if you guys have some different opinions.
>>>>>>>>>>
>>>>>>>>>> Thanks.
>>>>>>>>>>
>>>>>>>>>>
>>>>>>>>>>

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