When maxIndexBuildMemoryUsageMegabytes is set to a fractional value between 0 and 1 (which the code interprets as a percentage of total RAM), getTotalIndexBuildMaxMemoryUsageBytes() always returns 0 due to a variable shadowing bug: the inner size_t computedLimitBytes declaration on line 280 of multi_index_block.cpp shadows the outer one, so the computed percentage-based limit is never assigned to the variable that gets returned. This causes the sorter's memory limit to be set to 0 for any fractional parameter value, effectively breaking the percentage-based memory configuration path.