jrgemignani opened a new pull request, #2430:
URL: https://github.com/apache/age/pull/2430
Add two C set-returning functions that compute unweighted (hop-count)
shortest paths over the cached global graph adjacency via BFS, callable both at
the SQL top level and inside a cypher() RETURN:
- age_shortest_path(...) -> the single shortest path (0 or 1 rows)
- age_all_shortest_paths(...) -> every shortest path, one per row
The signature follows the natural Cypher argument order (graph, start, end,
edge_types, direction, min_hops, max_hops), registered in
sql/agtype_typecast.sql (install) and age--1.7.0--y.y.y.sql (upgrade).
Unimplemented parameters fail loudly: multiple relationship types and a
non-zero min_hops raise ERRCODE_FEATURE_NOT_SUPPORTED. A single edge type
(string or one-element array) is honored, and a NULL endpoint yields no rows
per Cypher null semantics (wrong-typed endpoints / NULL graph still error).
To call the SRFs inside a cypher() RETURN, transform_cypher_return now sets
query->hasTargetSRFs (it was the only results-producing clause that didn't, so
the planner never added a ProjectSet node), and transform_FuncCall
auto-prepends the graph name for snake_case shortest_path / all_shortest_paths.
camelCase names are reserved for the future native grammar.
Robustness:
- BFS guards against non-existent endpoints (returns 0 rows instead of
crashing) and honors CHECK_FOR_INTERRUPTS.
- An unknown edge label now matches no edges instead of silently
traversing all of them (get_label_relation returns InvalidOid).
- manage_GRAPH_global_contexts no longer self-deadlocks: its process-local
mutex is released via PG_TRY/PG_CATCH if the critical section errors.
Adds the age_shortest_path regression test (directed/undirected, label
filtering, parallel edges, self-loops, max_hops, the not-supported stubs, NULL
and non-existent endpoint/graph guards). 37/37 installcheck pass.
Co-authored-by: Claude [email protected]
modified: Makefile
modified: age--1.7.0--y.y.y.sql
new file: regress/expected/age_shortest_path.out
new file: regress/sql/age_shortest_path.sql
modified: sql/agtype_typecast.sql
modified: src/backend/parser/cypher_clause.c
modified: src/backend/parser/cypher_expr.c
modified: src/backend/utils/adt/age_global_graph.c
modified: src/backend/utils/adt/age_vle.c
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