[SPARK-16524][SQL] Add RowBatch and RowBasedHashMapGenerator #14349
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This PR is a cleaned version for #14174. |
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Test build #62839 has finished for PR 14349 at commit
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LGTM (from #14174) |
| * [8 bytes pointer to next] | ||
| * Thus, record length = 4 + 4 + klen + vlen + 8 | ||
| */ | ||
| public final class VariableLengthRowBasedKeyValueBatch extends RowBasedKeyValueBatch { |
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you can write the test suites in scala -- it tends to simplify the code.
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Merging in master. |
cloud-fan
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Feb 4, 2017
| * | ||
| * The format for each record looks like this: | ||
| * [UnsafeRow for key of length klen] [UnsafeRow for Value of length vlen] | ||
| * [8 bytes pointer to next] |
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why do we need a pointer? Since the key-value size is fixed, can we just use (klen + vlen) * n to address the n-th entry?
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The 8 byte is left intentionally for some compatibility reason. AFAIK, this is due the fact that sometimes a key can be followed by multiple values. @davies can probably explain it better.
HyukjinKwon
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Dec 10, 2024
…e to debug level
### What changes were proposed in this pull request?
This PR aims to lower `RowBasedKeyValueBatch.spill` warning message to debug level.
```java
public final long spill(long size, MemoryConsumer trigger) throws IOException {
- logger.warn("Calling spill() on RowBasedKeyValueBatch. Will not spill but return 0.");
+ logger.debug("Calling spill() on RowBasedKeyValueBatch. Will not spill but return 0.");
return 0;
}
```
### Why are the changes needed?
Although Apache Spark has been showing a warning message since 2.1.0, there is nothing for a user to be able to do further. This is more like a dev-side debug message. So, we had better lower the level to `DEBUG` from `WARN`.
- #14349
### Does this PR introduce _any_ user-facing change?
No behavior change. This is a log message.
### How was this patch tested?
Manual review.
### Was this patch authored or co-authored using generative AI tooling?
No.
Closes #49116 from dongjoon-hyun/SPARK-50524.
Authored-by: Dongjoon Hyun <dongjoon@apache.org>
Signed-off-by: Hyukjin Kwon <gurwls223@apache.org>
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What changes were proposed in this pull request?
This PR is the first step for the following feature:
For hash aggregation in Spark SQL, we use a fast aggregation hashmap to act as a "cache" in order to boost aggregation performance. Previously, the hashmap is backed by a
ColumnarBatch. This has performance issues when we have wide schema for the aggregation table (large number of key fields or value fields).In this JIRA, we support another implementation of fast hashmap, which is backed by a
RowBasedKeyValueBatch. We then automatically pick between the two implementations based on certain knobs.In this first-step PR, implementations for
RowBasedKeyValueBatchandRowBasedHashMapGeneratorare added.How was this patch tested?
Unit tests:
RowBasedKeyValueBatchSuite