spark-instrumented-optimizer/core/src
DB Tsai f4d5aa4213 [SPARK-29434][CORE] Improve the MapStatuses Serialization Performance
### What changes were proposed in this pull request?
Instead of using GZIP for compressing the serialized `MapStatuses`, ZStd provides better compression rate and faster compression time.

The original approach is serializing and writing data directly into `GZIPOutputStream` as one step; however, the compression time is faster if a bigger chuck of the data is processed by the codec at once. As a result, in this PR, the serialized data is written into an uncompressed byte array first, and then the data is compressed. For smaller `MapStatues`, we find it's 2x faster.

Here is the benchmark result.

#### 20k map outputs, and each has 500 blocks
1. ZStd two steps in this PR: 0.402 ops/ms, 89,066 bytes
2. ZStd one step as the original approach: 0.370 ops/ms, 89,069 bytes
3. GZip: 0.092 ops/ms, 217,345 bytes

#### 20k map outputs, and each has 5 blocks
1. ZStd two steps in this PR: 0.9 ops/ms, 75,449 bytes
2. ZStd one step as the original approach: 0.38 ops/ms, 75,452 bytes
3. GZip: 0.21 ops/ms, 160,094 bytes

### Why are the changes needed?
Decrease the time for serializing the `MapStatuses` in large scale job.

### Does this PR introduce any user-facing change?
No.

### How was this patch tested?
Existing tests.

Closes #26085 from dbtsai/mapStatus.

Lead-authored-by: DB Tsai <d_tsai@apple.com>
Co-authored-by: Dongjoon Hyun <dhyun@apple.com>
Signed-off-by: Dongjoon Hyun <dhyun@apple.com>
2019-10-20 13:56:23 -07:00
..
main [SPARK-29434][CORE] Improve the MapStatuses Serialization Performance 2019-10-20 13:56:23 -07:00
test [SPARK-29515][CORE] MapStatuses SerDeser Benchmark 2019-10-18 21:30:36 +00:00