pub fn record(path: AccessPath)Expand description
Record the access path chosen by a SELECT SSTable-scan step.
Called at each decision boundary in the executor. The last call before a test
reads last reflects the path the query actually took. The store is lock-free
and infallible (no poisoning surface); recording is a diagnostic side channel and
never aborts a query.
Additionally emits the degraded read-path counter
(cqlite.query.degraded_path.total, issue #2163) exactly when path is an
honest AccessPath::FallbackFullScan, carrying the bounded
FallbackReason::label as cqlite.query.fallback_reason. A targeted path
never increments it. The emission is a no-op with zero OTel linkage when the
observability feature is off.