tp: make FlexVector::shrink_to_fit a no-op at minimal capacity - #7198
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shrink_to_fit unconditionally reallocated and copied the storage even when capacity was already the smallest legal size for the current element count. Dataframe::Finalize calls it on every column of every built dataframe, so each finalize silently copied all column storage. That copy also defeats any downstream design that wants to share or move finalized column storage instead of duplicating it. Return early when the aligned size already equals capacity, making the call free in the common already-minimal case.
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stevegolton
approved these changes
Aug 25, 2026
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shrink_to_fit unconditionally reallocated and copied the storage even
when capacity was already the smallest legal size for the current
element count. Dataframe::Finalize calls it on every column of every
built dataframe, so each finalize silently copied all column storage.
That copy also defeats any downstream design that wants to share or
move finalized column storage instead of duplicating it.
Return early when the aligned size already equals capacity, making the
call free in the common already-minimal case.