update_spend_logs flushes the queue with a single create_many per batch, so one
row carrying bytes Postgres refuses (a residual NUL byte is the canonical case)
fails the entire insert and drops every good spend log alongside it. PR #29515
strips NUL bytes from the JSON columns, but the scalar string columns (end_user,
model, session_id, ...) still flow through unsanitized, so a poisoned row can
still reach the write and take a batch of up to 1000 good rows down with it.
On a genuine data-layer rejection the batch is now bisected so the good rows
still persist and only the offending row is dropped and logged with its
request_id. The classification lives in PrismaDBExceptionHandler.is_prisma_data_error
(matched by exact type so systemic subclasses like a missing table are not
mistaken for a single poison row), which keeps prisma an in-function import and
litellm.proxy.utils importable without the proxy extra. Transport failures,
including the "can't reach database server" outage that prisma mislabels as a
DataError, are re-raised unchanged so the existing connection-retry path still
runs and a transient outage never turns into silent per-row data loss.
The bisection carries a per-batch isolation budget so an authenticated caller
flooding poisoned rows cannot amplify one failed bulk insert into ~2N failed
inserts and N log lines; once the budget is spent the still-failing remainder
is dropped wholesale under a single log line.
Resolves LIT-4103
Any PrismaError should be treated as a DB connection error for the
allow_requests_on_db_unavailable feature and 503 responses. The narrow
keyword-based check is now in is_database_transport_error, which is
what the reconnect logic in auth_checks.py should use.
Fixes test_delete_access_group_503_on_db_connection_error and
test_handle_authentication_error_db_unavailable failures caused by
PR #21706 narrowing is_database_connection_error.
