Module drive_document_count_and_sum_query 

Joint count-and-sum no-prove executor surface — backs the AVG no-prove path’s unified single-walk dispatch. See its module docstring for the perf / atomicity contract. Server-only because the surface only fires on the no-prove (server-materialized) path. Joint count-and-sum executor surface for the AVG no-prove path.

Drive::execute_document_count_and_sum_request consumes the same DocumentAverageRequest / DocumentAverageResponse pair used by the prove path and dispatches to one of three per-mode executors depending on the resolved [DocumentSumMode].

Per-shape execution

• Total / PerInValue (empty-where, or Equal/In on a summable + countable index): point-lookup walk against the index, decoding (count, sum) from each visited CountSumTree / ProvableCountSumTree terminator in one call via Element::count_sum_value_or_default. One grovedb read per In branch yields both metrics together.
• RangeNoProof distinct shapes (GroupByRange / GroupByCompound + range on a rangeAverageable index): one grovedb walk against crate::query::drive_document_sum_query::DriveDocumentSumQuery::distinct_sum_path_query’s ProvableCountProvableSumTree terminators, emitting one (count, sum) per visited distinct in-range key. Bounded by the request’s limit (default falls back to drive_config.default_query_limit, explicit limits are clamped to drive_config.max_query_limit).
• RangeNoProof aggregate shapes (Aggregate / GroupByIn + range): grovedb’s combined merk-internal accumulator — query_aggregate_count_and_sum against the PCPS path query — yielding (u64, i64) from a single O(log n) traversal. Compound In + range per-In fans out (≤100 branches per the In::in_values() validator cap) and issues one combined accumulator call per branch under a shared read transaction.

Routing

Mode resolution reuses sum’s versioned routing table (crate::query::drive_document_sum_query::mode_detection::detect_sum_mode_from_inputs) — the routing decision is consensus-relevant and identical for count, sum, and joint count+sum on the no-prove path, so forking the table here would invite the drift bug PR #3661 caught (count’s GroupByCompound row had diverged from sum’s). A trivial AverageMode → SumMode adapter feeds sum’s mode detector; prove = false is passed unconditionally because the prove path never enters this module.

Engine-side primitive note

grovedb exposes query_aggregate_count_and_sum as the combined no-prove accumulator (proof-side analog AggregateCountAndSumOnRange is what the prove path uses for the same shape). The aggregate RangeNoProof branch routes through it directly — one merk-internal (u128, i128) walk per request, narrowed to (u64, i64) at the grovedb entry. Same cost class and the same shape the prove path uses, just without the proof envelope.

Modules

drive_dispatcher

Joint count-and-sum dispatcher entry point for the AVG no-prove path.

executors

Per-DocumentSumMode joint count-and-sum no-prove executors.