[format] Skip the CSV header only in the split that contains it - #9065
Open
thswlsqls wants to merge 1 commit into
Open
[format] Skip the CSV header only in the split that contains it#9065thswlsqls wants to merge 1 commit into
thswlsqls wants to merge 1 commit into
Conversation
CsvFileReader#setupReading skipped a line on every split, but the header only exists at byte 0. Splits with a non-zero offset therefore dropped their own first data row, so a header-bearing CSV larger than source.split.target-size silently lost one row per extra split. Generated-by: Claude Code
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
1 participant
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Outdated suggestions cannot be applied.This suggestion has been applied or marked resolved.Suggestions cannot be applied from pending reviews.Suggestions cannot be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.
Purpose
fix #9063
CsvFileReader#setupReadingskipped a line on every split, but the header only exists at byte 0, so a split withoffset > 0dropped its own first data row.source.split.target-sizelost one row per extra split.StandardLineReader#skipFirstLineand read in full by the previous split, so guarding onoffset == 0cannot duplicate rows and leaves the single-split path unchanged; a comment records this.Tests
CsvFileFormatTest#testHeaderSkippedOnlyInFirstSplit: reads a 50-row file as two segments viacreateReader(context, offset, length)and asserts no row is lost or duplicated, withcsv.include-headertrue and false. Fails on master (49 of 50 rows).mvn -pl paimon-format -DfailIfNoTests=false clean install— 530 tests passed.read()helper only usescreateReader(context).