fix: allow duplicate column names in query responses #2623
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Fixes client throwing errors like `Multiple entries with same key: number=1 and number=0` For queries with duplicate column names. IE: `select number, * from system.numbers limit 1;`
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| colIndexMapBuilder.put(columnName, i); | ||
| } | ||
| this.colIndex = colIndexMapBuilder.build(); | ||
| this.colIndex = colIndexMapBuilder; |
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The colIndex map is no longer immutable after switching from ImmutableMap to HashMap, but it's still exposed as a public field. Consider making this field private or ensuring it remains immutable by wrapping it with Collections.unmodifiableMap() to prevent external modifications.
chernser
reviewed
Oct 25, 2025
| this.query = query; | ||
| this.columns = ImmutableList.copyOf(columns); | ||
| ImmutableMap.Builder<String, Integer> colIndexMapBuilder = ImmutableMap.builder(); | ||
| Map<String, Integer> colIndexMapBuilder = new HashMap<>(); |
Contributor
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HashMap is much slower that ImmutableMap - that we have measured in our benchmark tests.
ImmutableMap allows to leave last value.
Contributor
|
Good day, @maxjustus ! Thank you for the contribution! However we have fix for the problem in review #2618 |
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Fixes client throwing errors like
Multiple entries with same key: number=1 and number=0For queries with duplicate column names. IE:select number, * from system.numbers limit 1;. Aligns withclickhouse clientwhich allows duplicate column names.