[BUG][Dataloader] preserve column casing in DataFusion SQL dialect to fix camelCase column lookups#536
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ShreyeshArangath merged 4 commits intolinkedin:mainfrom Apr 8, 2026
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…e column lookups The DataFusion dialect's NORMALIZATION_STRATEGY was set to LOWERCASE, causing sqlglot to lowercase all identifiers during SQL optimization. This broke tables with camelCase columns (e.g. viewerId, feedPosition) because both DataFusion execution and PyIceberg scans are case-sensitive. Change the strategy to CASE_SENSITIVE, which matches DataFusion's actual behavior and preserves original identifier casing throughout the pipeline. Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>
… tests Makes the test data truly ambiguous — all three columns lowercase to "userid", so a lowercasing dialect would collapse them into one column. Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>
…-case tests Renames generic userId/USERID/UserID to purchaseAmount/PURCHASEAMOUNT/ PurchaseAmount for better readability while preserving the case-collision property that makes the tests meaningful. Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>
Replaces colliding casing variants (purchaseAmount/PURCHASEAMOUNT/ PurchaseAmount) with distinct descriptive columns (purchaseAmount, itemCount, discountRate) that better represent a real schema. Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>
robreeves
approved these changes
Apr 8, 2026
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Summary
The DataFusion dialect's NORMALIZATION_STRATEGY was set to LOWERCASE, causing sqlglot to lowercase all identifiers during SQL optimization. This broke tables with camelCase columns (e.g. viewerId, feedPosition) because both DataFusion execution and PyIceberg scans are case-sensitive.
Change the strategy to CASE_SENSITIVE, which matches DataFusion's actual behavior and preserves original identifier casing throughout the pipeline.
Changes
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