feat: implement compressed CSV/JSON export functionality #7162
+1,629
−242
Conversation
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
github-actions
bot
added
size/M
docs-not-required
Contributor
|
Thanks. Question: Why deprecated LazyBufferedWriter? |
Contributor
There was a problem hiding this comment.
Pull Request Overview
This PR adds compression support for JSON and CSV export functionality in the COPY TO command. The implementation introduces a new CompressedWriter abstraction that wraps async writers with compression support for multiple formats (GZIP, BZIP2, XZ, ZSTD).
Key Changes:
- Added
compressed_writer.rsmodule withCompressedWriterandIntoCompressedWritertrait - Refactored
stream_to_filefunction to support compression for both JSON and CSV formats - Removed the
LazyBufferedWriterand associated error types as compression is now handled byCompressedWriter - Added comprehensive test cases for compressed exports in both CSV and JSON formats
Reviewed Changes
Copilot reviewed 13 out of 13 changed files in this pull request and generated 2 comments.
Show a summary per file
| File | Description |
|---|---|
| src/common/datasource/src/compressed_writer.rs | New module implementing compressed writer wrapper for multiple compression formats |
| src/common/datasource/src/file_format.rs | Refactored stream_to_file to support compression; replaced LazyBufferedWriter with direct buffer handling and compression |
| src/common/datasource/src/file_format/json.rs | Updated stream_to_json to accept JsonFormat parameter and pass compression type to stream_to_file; added compression tests |
| src/common/datasource/src/file_format/csv.rs | Updated stream_to_csv to pass compression type to stream_to_file; added compression tests |
| src/common/datasource/src/buffered_writer.rs | Removed LazyBufferedWriter implementation as it's no longer needed with the new compression approach |
| src/common/datasource/src/error.rs | Removed BufferedWriterClosed error variant that was specific to the old LazyBufferedWriter |
| src/common/datasource/src/lib.rs | Added compressed_writer module export |
| src/common/datasource/src/test_util.rs | Updated test utility to pass JsonFormat parameter to stream_to_json |
| src/operator/src/statement/copy_table_to.rs | Updated to pass JsonFormat to stream_to_json function |
| tests/cases/standalone/common/copy/copy_to_json_compressed.sql | New SQL test cases for compressed JSON exports |
| tests/cases/standalone/common/copy/copy_to_json_compressed.result | Expected results for compressed JSON export tests |
| tests/cases/standalone/common/copy/copy_to_csv_compressed.sql | New SQL test cases for compressed CSV exports |
| tests/cases/standalone/common/copy/copy_to_csv_compressed.result | Expected results for compressed CSV export tests |
💡 Add Copilot custom instructions for smarter, more guided reviews. Learn how to get started.
Member
As mentioned earlier in #6286, the main reason is that the OpenDAL writer already provides internal buffering during writes. |
WenyXu
reviewed
Oct 30, 2025
WenyXu
reviewed
Nov 12, 2025
tests/cases/standalone/common/copy/copy_from_csv_compressed.sql
Outdated
Show resolved
Hide resolved
tests/cases/standalone/common/copy/copy_from_json_compressed.sql
Outdated
Show resolved
Hide resolved
fengjiachun
reviewed
Nov 12, 2025
McKnight22
force-pushed
the
pr-add_compression_option
branch
from
617b3c7 to
18bdd41
Compare
github-actions
bot
added
docs-required
- Add CompressedWriter for real-time compression during CSV/JSON export - Support GZIP, BZIP2, XZ, ZSTD compression formats - Remove LazyBufferedWriter dependency for simplified architecture - Implement Encoder -> Compressor -> FileWriter data flow - Add tests for compressed CSV/JSON export Signed-off-by: McKnight22 <[email protected]>
- refactor and extend compressed_writer tests - add coverage for Bzip2 and Xz compression Signed-off-by: McKnight22 <[email protected]>
- Switch to threshold-based chunked flushing - Avoid unnecessary writes on empty buffers - Replace direct write_all() calls with the new helper for consistency Signed-off-by: McKnight22 <[email protected]>
- Add support for reading compressed CSV and JSON in COPY FROM - Support GZIP, BZIP2, XZ, ZSTD compression formats - Add tests for compressed CSV/JSON import Signed-off-by: McKnight22 <[email protected]>
- Fix review comments Signed-off-by: McKnight22 <[email protected]>
- Move temp_dir out of the loop Signed-off-by: McKnight22 <[email protected]>
McKnight22
force-pushed
the
pr-add_compression_option
branch
from
a55ff8c to
bc93f58
Compare
Sign up for free
to join this conversation on GitHub.
Already have an account?
Sign in to comment
4 participants
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.
I hereby agree to the terms of the GreptimeDB CLA.
Refer to a related PR or issue link (optional)
#6286
What's changed and what's your intention?
Summary (mandatory):
This PR introduces support for GZIP, BZIP2, XZ, ZSTD compression in the COPY TO statement for CSV/JSON exports.
Details:
Added CompressionType option to specify file export compression formats: GZIP, BZIP2, XZ, ZSTD.
Deprecated LazyBufferedWriter and simplify the data flow to Encoder -> Compressor -> FileWriter.
Implemented compressed file export functionality only for CSV and JSON.
PR Checklist
Please convert it to a draft if some of the following conditions are not met.