perf: hash-adjacency overhaul

Makefile

@@ -127,6 +127,7 @@ OBJS = src/backend/age.o \
        src/backend/utils/ag_func.o \
        src/backend/utils/graph_generation.o \
        src/backend/utils/cache/ag_cache.o \
+       src/backend/utils/cache/agehash.o \
        src/backend/utils/load/ag_load_labels.o \
        src/backend/utils/load/ag_load_edges.o \
        src/backend/utils/load/age_load.o \
@@ -153,6 +154,7 @@ REGRESS = scan \
           graphid \
           agtype \
           agtype_hash_cmp \
+          agehash \
           catalog \
           cypher \
           expr \

age--1.7.0--y.y.y.sql

@@ -459,3 +459,13 @@ BEGIN
     END LOOP;
 END;
 $$;
+
+-- Internal selftest for the agehash open-addressing hashtable. Returns "OK"
+-- on success or "FAIL: ..." with a diagnostic message. Intended for the
+-- agehash regression test only.
+CREATE FUNCTION ag_catalog._agehash_self_test()
+    RETURNS text
+    LANGUAGE c
+    VOLATILE
+    PARALLEL UNSAFE
+AS 'MODULE_PATHNAME';

regress/expected/agehash.out

@@ -0,0 +1,14 @@
+/*
+ * agehash internal selftest.
+ *
+ * Exercises the Robin Hood open-addressing hashtable used by AGE's hot-path
+ * caches at boundary sizes (1, 7, 8, 9, 63, 64, 65, 1024, ...) and across
+ * grow thresholds. A success returns the literal "OK"; any failure returns
+ * "FAIL: <reason>" describing the offending case.
+ */
+SELECT ag_catalog._agehash_self_test();
+ _agehash_self_test 
+--------------------
+ OK
+(1 row)
+

regress/sql/agehash.sql

@@ -0,0 +1,9 @@
+/*
+ * agehash internal selftest.
+ *
+ * Exercises the Robin Hood open-addressing hashtable used by AGE's hot-path
+ * caches at boundary sizes (1, 7, 8, 9, 63, 64, 65, 1024, ...) and across
+ * grow thresholds. A success returns the literal "OK"; any failure returns
+ * "FAIL: <reason>" describing the offending case.
+ */
+SELECT ag_catalog._agehash_self_test();

sql/age_main.sql

@@ -86,6 +86,16 @@ CREATE FUNCTION ag_catalog._label_id(graph_name name, label_name name)
 PARALLEL SAFE
 AS 'MODULE_PATHNAME';
 
+-- Internal selftest for the agehash open-addressing hashtable. Returns "OK"
+-- on success or "FAIL: ..." with a diagnostic message. Intended for the
+-- agehash regression test only.
+CREATE FUNCTION ag_catalog._agehash_self_test()
+    RETURNS text
+    LANGUAGE c
+    VOLATILE
+    PARALLEL UNSAFE
+AS 'MODULE_PATHNAME';
+
 --
 -- utility functions
 --