fix: account for initial hash table allocation in ArrowBytesMap/ArrowBytesViewMap#21249
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yashrb24 wants to merge 3 commits intoapache:mainfrom
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fix: account for initial hash table allocation in ArrowBytesMap/ArrowBytesViewMap#21249yashrb24 wants to merge 3 commits intoapache:mainfrom
yashrb24 wants to merge 3 commits intoapache:mainfrom
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…BytesViewMap ArrowBytesMap and ArrowBytesViewMap initialize their hash table with with_capacity(INITIAL_MAP_CAPACITY) but set map_size to 0. The insert_accounted method only tracks incremental growth beyond the current capacity, so the initial allocation is never counted in size() — understating memory usage. Initialize map_size with map.allocation_size() to capture the pre-allocated memory.
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Verify that ArrowBytesMap::size() and ArrowBytesViewMap::size() account for the hash table memory pre-allocated by HashTable::with_capacity(). Both tests fail without the fix (map_size: 0) and pass with it.
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Which issue does this PR close?
Rationale for this change
ArrowBytesMapandArrowBytesViewMapallocate their hash tables withHashTable::with_capacity(INITIAL_MAP_CAPACITY)but initializemap_sizeto0. Theinsert_accountedmethod only tracks incremental growth beyond the current capacity, so the initial allocation fromwith_capacityis never counted.size()understates memory usage until the first resize.What changes are included in this PR?
Initialize
map_sizewithmap.allocation_size()in bothArrowBytesMap::newandArrowBytesViewMap::newto capture the pre-allocated memory.Are these changes tested?
The change is a one-line init fix. Existing tests cover the
size()method behavior.Are there any user-facing changes?
No API changes.
size()now returns the memory estimate that includes the initial hash table allocation.