Use BufferedOutputStream when writing the Zip file to improve performance#1579
Merged
Goooler merged 3 commits intoGradleUp:8.xfrom Aug 5, 2025
Merged
Conversation
When not using STORED entries use a BufferedOutputStream to avoid lots of small writes to the file system. Testing this with a 300mb jar build I see the total build time going from 40s to 30s. Note that it is not possible to do this with STORED entries as the implementation requires a RandomAccessFile to update the CRC after write.
c6d623a to
37b2918
Compare
Goooler
approved these changes
Aug 5, 2025
BufferedOutputStream when writing the Zip file to improve performance
Contributor
There was a problem hiding this comment.
Pull Request Overview
This PR improves ZIP file creation performance by using BufferedOutputStream for non-STORED compression methods. The change conditionally wraps the file output stream with a buffer to reduce system call overhead during ZIP file writing.
Key changes:
- Modified
DefaultZipCompressorto conditionally useBufferedOutputStreambased on compression method - Added changelog entry documenting the performance improvement
Reviewed Changes
Copilot reviewed 2 out of 2 changed files in this pull request and generated 1 comment.
| File | Description |
|---|---|
| DefaultZipCompressor.groovy | Adds conditional buffering logic to improve ZIP writing performance for non-STORED entries |
| README.md | Documents the performance improvement in the changelog |
src/main/groovy/com/github/jengelman/gradle/plugins/shadow/internal/DefaultZipCompressor.groovy
Show resolved
Hide resolved
Goooler
reviewed
Aug 5, 2025
src/main/groovy/com/github/jengelman/gradle/plugins/shadow/internal/DefaultZipCompressor.groovy
Outdated
Show resolved
Hide resolved
…ernal/DefaultZipCompressor.groovy
dongjoon-hyun
added a commit
to apache/spark-kubernetes-operator
that referenced
this pull request
Jan 20, 2026
### What changes were proposed in this pull request? This PR aims to upgrade `com.gradleup.shadow` to 8.3.9. ### Why are the changes needed? To bring the latest bug fixed versions. - https://github.com/GradleUp/shadow/releases/tag/8.3.9 - GradleUp/shadow#1579 - https://github.com/GradleUp/shadow/releases/tag/8.3.8 - GradleUp/shadow#1493 - GradleUp/shadow#1488 - https://github.com/GradleUp/shadow/releases/tag/8.3.7 - GradleUp/shadow#1470 ### Does this PR introduce _any_ user-facing change? No. ### How was this patch tested? Pass the CIs. ### Was this patch authored or co-authored using generative AI tooling? No. Closes #469 from dongjoon-hyun/SPARK-55102. Authored-by: Dongjoon Hyun <dongjoon@apache.org> Signed-off-by: Dongjoon Hyun <dongjoon@apache.org>
This file contains hidden or bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters
Sign up for free
to join this conversation on GitHub.
Already have an account?
Sign in to comment
Add this suggestion to a batch that can be applied as a single commit.This suggestion is invalid because no changes were made to the code.Suggestions cannot be applied while the pull request is closed.Suggestions cannot be applied while viewing a subset of changes.Only one suggestion per line can be applied in a batch.Add this suggestion to a batch that can be applied as a single commit.Applying suggestions on deleted lines is not supported.You must change the existing code in this line in order to create a valid suggestion.Outdated suggestions cannot be applied.This suggestion has been applied or marked resolved.Suggestions cannot be applied from pending reviews.Suggestions cannot be applied on multi-line comments.Suggestions cannot be applied while the pull request is queued to merge.Suggestion cannot be applied right now. Please check back later.
When not using STORED entries use a BufferedOutputStream to avoid lots of small writes to the file system.
Testing this with a 300mb jar build I see the total build time going from 40s to 30s.
Note that it is not possible to do this with STORED entries as the implementation requires a RandomAccessFile to update the CRC after write.