[HUDI-1887] Setting default value to false for enabling schema post processor

[nsivabalan]

What is the purpose of the pull request

https://issues.apache.org/jira/browse/HUDI-1343 was added so that default and nulls are handled properly. This fix is applicable only to deltastreamer flow. But later, we had a fix in spark ds layer which fixed the defaults and null values. So, the schema post processor is not really required anymore. Hence making the default value to disabled.

Brief change log

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• Modify AnnotationLocation checkstyle rule in checkstyle.xml

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Committer checklist

• Has a corresponding JIRA in PR title & commit

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[codecov-commenter]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 52.90%. Comparing base (c5220b9) to head (701640c).
Report is 4136 commits behind head on master.

Additional details and impacted files

@@            Coverage Diff            @@
##             master    #2911   +/-   ##
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  Coverage     52.90%   52.90%           
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  Lines         23574    23574           
  Branches       2510     2510           
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  Hits          12472    12472           
- Misses         9998     9999    +1     
+ Partials       1104     1103    -1     

Flag	Coverage Δ
hudicli	39.53% <ø> (ø)
hudiclient	∅ <ø> (∅)
hudicommon	50.38% <ø> (+0.01%)	⬆️
hudiflink	58.98% <ø> (ø)
hudihadoopmr	33.33% <ø> (ø)
hudisparkdatasource	73.33% <ø> (ø)
hudisync	46.73% <ø> (ø)
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hudiutilities	69.43% <100.00%> (-0.10%)	⬇️

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Files with missing lines	Coverage Δ
...in/java/org/apache/hudi/utilities/UtilHelpers.java	63.37% <100.00%> (-1.17%)	⬇️

... and 1 file with indirect coverage changes

[n3nash]

LGTM. Will wait for @bvaradar to confirm later tonight/tomorrow before merging this.

[vinothchandar]

@nsivabalan are n't there any tests affected by this change? Also do we even need this post processor feature anymore? Should can the entire feature instead of just making it not enabled by default?

[nsivabalan]

yeah, I am trying to understand the implications of removing the post processor. we may not have namespace in delta streamer's target schema if we remove the post processor. so what we need to understand is, what incase schema has namespace in hudi data files, and then delta streamer produces records w/ schema not having namespace. marking as WIP for now.

[nsivabalan]

yes, Only reason we still wanted to have is, just incase some user wishes to migrate from a path of having namespace to a path of not having namespace. but if we can totally remove it, I am all for it.

[nsivabalan]

@n3nash : could you think of any reason why we need to have this instead of removing it altogether.

[n3nash]

@nsivabalan It's the same reason you mentioned. The post processor adds the namespace. So if users have written log files with AVRO name-spacing and we disable post process for them, it will break. But this only happens in a specific path of DeltaSync - can you point out which one ? From my interactions in the community, I can suggest whether that path is a frequently used path or not - if it's not, let's remove this complexity.

[nsivabalan]

@n3nash : when there is no target schema set and so hudi falls back to RowBasedSchemaProvider for target shema.

[vinothchandar]

I am marking this a non-blocker.

[nsivabalan]

@vinothchandar : If you are good with the patch, I can rebase and land it.

[hudi-bot]

CI report:

• 701640c Azure: FAILURE

Bot commands

@hudi-bot supports the following commands:

• @hudi-bot run azure re-run the last Azure build

[yihua]

We have added more SchemaPostProcessor implementation since this PR is posted, including ChainedSchemaPostProcessor, KafkaOffsetPostProcessor, DropColumnSchemaPostProcessor, and DeleteSupportSchemaPostProcessor, we cannot disable it by default any more. Closing this PR.