Fix #16836: rewrite main column data in case of an update that only modifies the validity#16851
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Mytherin merged 2 commits intoduckdb:v1.2-histrionicusfrom Mar 27, 2025
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…only modifies the validity
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…lues when reading files created by older versions of DuckDB
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On second thought - I've reworked the PR to revert #15737 instead. While we can fix this on the writing side, when reading files created by older versions of DuckDB we would still produce incorrect results without reverting that PR. In effect - we can no longer rely on dictionary compression correctly containing |
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Fix duckdb/duckdb#16836: rewrite main column data in case of an update that only modifies the validity (duckdb/duckdb#16851)
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Fixes #16836
This regression was caused by #15737
Effectively that change introduced an optimization for dictionary-compressed data where the validity data would be read directly from the dictionary - instead of being read from the separate validity data. This is possible because dictionary-compressed data stores validity data (at offset 0 in the dictionary).
However, when doing an
UPDATE, we would not rewrite the dictionary data when changing only the validity - which would then cause the dictionary column to no longer contain the new (updated) validity data. The fix here is to also rewrite the main column data when updating the validity data.Note that we currently do this for all primitive types - we could limit this to compression methods (like dictionary) that need this - but we can leave that for a future PR. (CC @Tishj).