Re-uploading a large export with an externalId column ran one
updateMany per row inside a single interactive transaction; on a
9 000-row file that outlived Prisma's 5 s timeout and the request ended
in a 500.
A re-imported externalId row whose stored value, unit, instant, glucose
context and note already match the line is now a duplicate: not written,
reported as skipped / duplicate. Changed rows still update, a tombstoned
one is still resurrected. The existence probes run per measurement type
in chunks of 1 000 keys, and the writes commit in chunks of 200 (creates
via createManyAndReturn, updates as one batch transaction per chunk)
instead of one transaction around the whole file. A failure part-way
leaves earlier chunks written, and re-uploading the same file completes
the rest.
The OpenAPI description now says what a re-upload does, including the
natural-key dedup for rows without an externalId, which it used to call
a duplicate.
