apache / apache/parquet-java

[Vectorized Reader] Add attributes in ColumnVector and RowBatch

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Component: Java Component: Parquet Priority: Major Type: task
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描述

As discussed in HIVE-8128, we want to add some attributes in vector.

- In `ColumnVector`, add two attributes: one is `boolean noNulls`, which indicates whether the whole column vector has no null value. The other is `boolean isRepeating`, which indicates whether the same value repeats for whole column vector. They could be calculated at the same time when we read a vector. SQL engines (like Hive) can check these attribute to skip some values.
- In `RowBatch`, add one attribute `int size`, which indicates the number of rows in this batch. This is just for easy usage. Its value should be the same as `RowBatch.columns\[0\].numValues`.

**Reporter**: [Dong Chen](https://issues.apache.org/jira/secure/ViewProfile.jspa?name=dongc) / @dongc
**Assignee**: [Nezih Yigitbasi](https://issues.apache.org/jira/secure/ViewProfile.jspa?name=nezihyigitbasi) / @nezihyigitbasi

**Note**: *This issue was originally created as [PARQUET-333](https://issues.apache.org/jira/browse/PARQUET-333). Please see the [migration documentation](https://issues.apache.org/jira/browse/PARQUET-2502) for further details.*

贡献指南

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调研方向

首先定位 ColumnVector、RowBatch 以及向量化 reader 的实现。跟踪向量和 batch 在哪里被填充,然后验证 noNulls、isRepeating 和 size 是否符合所述语义,并确认现有的 reader 测试覆盖了生成的元数据。

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