[
https://issues.apache.org/jira/browse/BEAM-10277?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel
]
Brian Hulette updated BEAM-10277:
---------------------------------
Description:
h3. Problem/Status
The schema proto has an [encoding_position
field|https://github.com/apache/beam/blob/2c619c81082839e054f16efee9311b9f74b6e436/model/pipeline/src/main/proto/schema.proto#L55]
that is currently unused in every row coder implementation. The intention of
this field is that it indicates an alternative order for the fields to be
encoded in by [beam:coder:row:v1
implementations|https://github.com/apache/beam/blob/1e60f383fb39b9ff8d44edcbe5357da4c1e52378/model/pipeline/src/main/proto/beam_runner_api.proto#L937-L990].
Currently all the implementations ignore this field, and always encode the
fields in the order that they appear in the schema.
h3. Motivation
The idea with the encoding position is that it will give runners a way to
enforce schema compatibility (BEAM-9502), by re-ordering the way fields are
encoded when the schema changes between two job submissions. Schema changes
could be due to fields re-ordering, or field additions/deletions.
h3. Code pointers
The Python beam:coder:row:v1 implementation lives in
[row_coder.py|https://github.com/apache/beam/blob/master/sdks/python/apache_beam/coders/row_coder.py]
The Java implementation is a little more complicated, distributed between
[SchemaCoder|https://github.com/apache/beam/blob/master/sdks/java/core/src/main/java/org/apache/beam/sdk/schemas/SchemaCoder.java],
[RowCoder|https://github.com/apache/beam/blob/master/sdks/java/core/src/main/java/org/apache/beam/sdk/coders/RowCoder.java],
and
[RowCoderGenerator|https://github.com/apache/beam/blob/master/sdks/java/core/src/main/java/org/apache/beam/sdk/coders/RowCoderGenerator.java].
RowCoderGenerator contains the code relevant to this jira - it uses bytebuddy
to generate Java code for the coder. We need it to generate code that puts
fields in the order specified by encoding_position.
h3. Testing
Python and Java implementations should be tested with unit tests
([RowCoderTest|https://github.com/apache/beam/blob/master/sdks/java/core/src/test/java/org/apache/beam/sdk/coders/RowCoderTest.java],
[row_coder_test|https://github.com/apache/beam/blob/master/sdks/python/apache_beam/coders/row_coder_test.py]).
We should also test them for compatibility by adding test cases that exercise
the encoding_position in
[standard_coders.yaml|https://github.com/apache/beam/blob/master/model/fn-execution/src/main/resources/org/apache/beam/model/fnexecution/v1/standard_coders.yaml].
These tests will be executed by
[CommonCoderTest|https://github.com/apache/beam/blob/master/runners/core-construction-java/src/test/java/org/apache/beam/runners/core/construction/CommonCoderTest.java]
and
[standard_coders_test|https://github.com/apache/beam/blob/master/sdks/python/apache_beam/coders/standard_coders_test.py].
There's some example code for generating a new test case
[here|https://github.com/apache/beam/blob/master/model/fn-execution/src/main/resources/org/apache/beam/model/fnexecution/v1/standard_coders.yaml#L387-L400].
was:
h3. Problem/Status
The schema proto has an [encoding_position
field|https://github.com/apache/beam/blob/2c619c81082839e054f16efee9311b9f74b6e436/model/pipeline/src/main/proto/schema.proto#L55]
that is currently unused in every row coder implementation. The intention of
this field is that it indicates an alternative order for the fields to be
encoded in by [beam:coder:row:v1
implementations|https://github.com/apache/beam/blob/1e60f383fb39b9ff8d44edcbe5357da4c1e52378/model/pipeline/src/main/proto/beam_runner_api.proto#L937-L990].
Currently all the implementations ignore this field, and always encode the
fields in the order that they appear in the schema.
h3. Motivation
The idea with the encoding position is that it will give runners away to
enforce schema compatibility (BEAM-9502), by re-ordering the way fields are
encoded when the schema changes between two job submissions. Schema changes
could be due to fields re-ordering, or field additions/deletions.
h3. Code pointers
The Python beam:coder:row:v1 implementation lives in
[row_coder.py|https://github.com/apache/beam/blob/master/sdks/python/apache_beam/coders/row_coder.py]
The Java implementation is a little more complicated, distributed between
[SchemaCoder|https://github.com/apache/beam/blob/master/sdks/java/core/src/main/java/org/apache/beam/sdk/schemas/SchemaCoder.java],
[RowCoder|https://github.com/apache/beam/blob/master/sdks/java/core/src/main/java/org/apache/beam/sdk/coders/RowCoder.java],
and
[RowCoderGenerator|https://github.com/apache/beam/blob/master/sdks/java/core/src/main/java/org/apache/beam/sdk/coders/RowCoderGenerator.java].
RowCoderGenerator contains the code relevant to this jira - it uses bytebuddy
to generate Java code for the coder. We need it to generate code that puts
fields in the order specified by encoding_position.
h3. Testing
Python and Java implementations should be tested with unit tests
([RowCoderTest|https://github.com/apache/beam/blob/master/sdks/java/core/src/test/java/org/apache/beam/sdk/coders/RowCoderTest.java],
[row_coder_test|https://github.com/apache/beam/blob/master/sdks/python/apache_beam/coders/row_coder_test.py]).
We should also test them for compatibility by adding test cases that exercise
the encoding_position in
[standard_coders.yaml|https://github.com/apache/beam/blob/master/model/fn-execution/src/main/resources/org/apache/beam/model/fnexecution/v1/standard_coders.yaml].
These tests will be executed by
[CommonCoderTest|https://github.com/apache/beam/blob/master/runners/core-construction-java/src/test/java/org/apache/beam/runners/core/construction/CommonCoderTest.java]
and
[standard_coders_test|https://github.com/apache/beam/blob/master/sdks/python/apache_beam/coders/standard_coders_test.py].
There's some example code for generating a new test case
[here|https://github.com/apache/beam/blob/master/model/fn-execution/src/main/resources/org/apache/beam/model/fnexecution/v1/standard_coders.yaml#L387-L400].
> beam:coder:row:v1 implementations should respect encoding_position
> ------------------------------------------------------------------
>
> Key: BEAM-10277
> URL: https://issues.apache.org/jira/browse/BEAM-10277
> Project: Beam
> Issue Type: Improvement
> Components: sdk-java-core, sdk-py-core
> Reporter: Brian Hulette
> Assignee: Irwin Alejandro Rodirguez Ramirez
> Priority: P3
> Labels: Clarified
> Time Spent: 7h 50m
> Remaining Estimate: 0h
>
> h3. Problem/Status
> The schema proto has an [encoding_position
> field|https://github.com/apache/beam/blob/2c619c81082839e054f16efee9311b9f74b6e436/model/pipeline/src/main/proto/schema.proto#L55]
> that is currently unused in every row coder implementation. The intention of
> this field is that it indicates an alternative order for the fields to be
> encoded in by [beam:coder:row:v1
> implementations|https://github.com/apache/beam/blob/1e60f383fb39b9ff8d44edcbe5357da4c1e52378/model/pipeline/src/main/proto/beam_runner_api.proto#L937-L990].
> Currently all the implementations ignore this field, and always encode the
> fields in the order that they appear in the schema.
> h3. Motivation
> The idea with the encoding position is that it will give runners a way to
> enforce schema compatibility (BEAM-9502), by re-ordering the way fields are
> encoded when the schema changes between two job submissions. Schema changes
> could be due to fields re-ordering, or field additions/deletions.
> h3. Code pointers
> The Python beam:coder:row:v1 implementation lives in
> [row_coder.py|https://github.com/apache/beam/blob/master/sdks/python/apache_beam/coders/row_coder.py]
> The Java implementation is a little more complicated, distributed between
> [SchemaCoder|https://github.com/apache/beam/blob/master/sdks/java/core/src/main/java/org/apache/beam/sdk/schemas/SchemaCoder.java],
>
> [RowCoder|https://github.com/apache/beam/blob/master/sdks/java/core/src/main/java/org/apache/beam/sdk/coders/RowCoder.java],
> and
> [RowCoderGenerator|https://github.com/apache/beam/blob/master/sdks/java/core/src/main/java/org/apache/beam/sdk/coders/RowCoderGenerator.java].
> RowCoderGenerator contains the code relevant to this jira - it uses
> bytebuddy to generate Java code for the coder. We need it to generate code
> that puts fields in the order specified by encoding_position.
> h3. Testing
> Python and Java implementations should be tested with unit tests
> ([RowCoderTest|https://github.com/apache/beam/blob/master/sdks/java/core/src/test/java/org/apache/beam/sdk/coders/RowCoderTest.java],
>
> [row_coder_test|https://github.com/apache/beam/blob/master/sdks/python/apache_beam/coders/row_coder_test.py]).
> We should also test them for compatibility by adding test cases that
> exercise the encoding_position in
> [standard_coders.yaml|https://github.com/apache/beam/blob/master/model/fn-execution/src/main/resources/org/apache/beam/model/fnexecution/v1/standard_coders.yaml].
> These tests will be executed by
> [CommonCoderTest|https://github.com/apache/beam/blob/master/runners/core-construction-java/src/test/java/org/apache/beam/runners/core/construction/CommonCoderTest.java]
> and
> [standard_coders_test|https://github.com/apache/beam/blob/master/sdks/python/apache_beam/coders/standard_coders_test.py].
> There's some example code for generating a new test case
> [here|https://github.com/apache/beam/blob/master/model/fn-execution/src/main/resources/org/apache/beam/model/fnexecution/v1/standard_coders.yaml#L387-L400].
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