The MATERIALIZED-CTE scalar guard forced Postgres to materialize all object
rows with their full JSON (~100 GB) to temp before json_each — on NFS that's a
huge spill and pathologically slow (risks disk-full). Replace with an inline
CASE that feeds json_each an empty object for non-object rows: same scalar
guard, but a single streaming pass with no materialization.
Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>
bvandeusen