[Vectorized Reader] Add attributes in ColumnVector and RowBatch
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- Java
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Description
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.*
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Research direction
Start by locating ColumnVector, RowBatch, and the vectorized reader implementation. Trace where vectors and batches are populated, then verify that noNulls, isRepeating, and size match the stated semantics and that existing reader tests cover the resulting metadata.
Written by the indexing model from the issue text.
Assessment
- Tech stack
- java
- Domain
- data-engineering
- Issue type
- Feature
- Difficulty
- 3/5
- Estimated time
- 1-2 days
- Activity status
- Stale
- Clarity
- Mostly clear
- Newbie friendliness
- 35/100