Module merge 

Merge functions for distributed array query results.

Slice merges concatenate row sets from shards in arrival order and apply the coordinator-side limit. The output preserves each shard’s intra-shard order; cross-shard ordering reflects arrival, since the wire response (ArrayShardSliceResp::rows_msgpack) is a flat opaque Vec<Vec<u8>> with no per-row sort key. A globally Hilbert-ordered merge would require carrying a parallel prefix column on the wire and a k-way merge here — that is a wire-format change, not a merger change, and lives outside this module.

Aggregate merges combine per-shard partial aggregates using reducer-specific arithmetic (SUM/COUNT/MIN/MAX — same Welford technique as the timeseries merger).

Structs

ArrayAggPartial

Partial aggregate contributed by a single shard for one group-by bucket.

Functions

any_truncated_before_horizon_agg

Returns true if any shard reported that system_as_of fell below its oldest tile version, causing the shard to contribute zero partials.

any_truncated_before_horizon_slice

Returns true if any shard reported that system_as_of fell below its oldest tile version and it produced zero rows as a result.

merge_slice_rows

Merge row batches from multiple shards into one result set.

reduce_agg_partials

Merge per-shard partial aggregates into one result per group-by key.