The sorter’s preflight disk-space check (ensureSufficientDiskSpaceForSpilling) is currently wired only into the file-based spiller and is driven by a query-focused knob (internalQuerySpillingMinAvailableDiskSpaceBytes). 

Background / Current behavior

• File-based sorter spilling does:

• • Estimate required space for a merge batch as the sum of spill-range byte lengths.
  • Take the max of that and internalQuerySpillingMinAvailableDiskSpaceBytes.
  • Call ensureSufficientDiskSpaceForSpilling(tempDir, minRequiredDiskSpace) and fail early with OutOfDiskSpace if not enough room.
• The controlling knob name and placement (internalQuerySpillingMinAvailableDiskSpaceBytes under query knobs) strongly suggests it was designed for query/agg spill behavior, but it now effectively governs all file-based sorter usages, including index build paths.