branch-4.0: [fix](parquet) Fix struct column reading error when all queried fields are missing after schema evolution #59586 #59839
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…s are missing after schema evolution (#59586) ### What problem does this PR solve? - relate pr: #57204 **Problem Summary:** When querying struct fields in Iceberg tables after schema evolution, if all queried struct fields are missing in old Parquet files, the code fails with error: ``` File column name 'removed' not found in struct children ``` **Root Cause:** When all queried struct sub-fields are missing in the old Parquet file (e.g., newly added fields after schema evolution), the code needs to find a reference column from the file schema to get repetition level (RL) and definition level (DL) information. However, if the reference column (e.g., `removed`) was dropped from the table schema, calling `root_node->get_children_node_by_file_column_name()` will fail because the column doesn't exist in `root_node`. **Scenario:** 1. Create table with struct containing: `removed`, `rename`, `keep`, `drop_and_add` 2. Insert data (creates Parquet file with these fields) 3. Perform schema evolution: DROP `a_struct.removed`, DROP then ADD `a_struct.drop_and_add` (gets new field ID), ADD `a_struct.added` 4. Query `struct_element(a_struct, 'drop_and_add')` or `struct_element(a_struct, 'added')` on the old file 5. The query fails because: - All queried fields (`drop_and_add`, `added`) are missing in the old file - Code tries to use `removed` as reference column (it exists in file but was dropped from table schema) - Accessing `removed` via `root_node` fails because it doesn't exist in table schema ### Solution: Use `TableSchemaChangeHelper::ConstNode::get_instance()` instead of looking up from `root_node` for the reference column. Since the reference column is only used to get RL/DL information (not for schema mapping), using `ConstNode` is safe and avoids the issue where the reference column doesn't exist in `root_node`. ### Release note None ### Check List (For Author) - Test <!-- At least one of them must be included. --> - [ ] Regression test - [ ] Unit Test - [ ] Manual test (add detailed scripts or steps below) - [ ] No need to test or manual test. Explain why: - [ ] This is a refactor/code format and no logic has been changed. - [ ] Previous test can cover this change. - [ ] No code files have been changed. - [ ] Other reason <!-- Add your reason? --> - Behavior changed: - [ ] No. - [ ] Yes. <!-- Explain the behavior change --> - Does this need documentation? - [ ] No. - [ ] Yes. <!-- Add document PR link here. eg: apache/doris-website#1214 --> ### Check List (For Reviewer who merge this PR) - [ ] Confirm the release note - [ ] Confirm test cases - [ ] Confirm document - [ ] Add branch pick label <!-- Add branch pick label that this PR should merge into -->
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Thank you for your contribution to Apache Doris. Please clearly describe your PR:
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run buildall |
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skip buildall |
yiguolei
approved these changes
Jan 14, 2026
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Cherry-picked from #59586