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fix(processor): zero tuples handed out again after a shrinking resize - #1323
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Shrinking a FactorizedTable with resize() gave tuples back to the block without counting them as uninitialized, so growing the table again handed out the old tuples' bytes instead of zeros. The only shrinking caller (HashTableQueue::mergeInto) never grows the table again, so nothing hits this today. DataBlock::truncate() gives the bytes back and marks them to be zeroed when claimed again. Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
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This work was produced with the help of language models.
Follow-up to #1300 (review nit).
FactorizedTable::resize()to fewer tuples gave the tuples back to the block without counting them as uninitialized, so growing the table again handed out the old tuples' bytes instead of zeros. Nothing hits this today: the only shrinking caller,HashTableQueue::mergeInto, only reads the shrunk table and deletes it, so that path does no extra zeroing either.Fix. The shrink branch goes through
DataBlock::truncate(), which gives the bytes back and setsnumUninitializedBytes = freeSize, so they are zeroed when claimed again. A DASSERT checks it only shrinks.Tests.
FactorizedTableTest.TuplesAreZeroAfterShrinkAndRegrowshrinks a table to 5 tuples and regrows it viaresize()andappendEmptyTuple()across several 4 KB zeroing steps; the regrown tuples must be zero and the kept ones intact. It fails without the new line. Full ctest: 3118/3118.