Remove chunk_constraint catalog tracking for non-dimensional constraints

Rely on postgres for tracking non-dimensional constraints

Author: svenklemm

.unreleased/pr_9893

@@ -0,0 +1 @@
+Implements: #9893 Remove chunk_constraint catalog tracking for non-dimensional constraints

sql/updates/latest-dev.sql

@@ -8,50 +8,45 @@ WHERE cc.chunk_id = c.id
   AND cc.hypertable_constraint_name IS NOT NULL
   AND cc.constraint_name = cc.hypertable_constraint_name;
 
--- Rename legacy <chunk_id>_<seq>_<parent> chunk-side FKs to the parent name
--- so the event-trigger hooks can locate them by name on DROP/RENAME.
+-- Rename legacy chunk-side constraints to the names the new code recomputes:
+-- FKs use the parent's name; unique/PK/exclusion/trigger use the deterministic
+-- "<chunk_id>_<parent>" form
 DO $$
 DECLARE
     r RECORD;
 BEGIN
     FOR r IN
         SELECT pg_catalog.format('%I.%I', c.schema_name, c.table_name) AS chunk_table,
                cc.constraint_name AS old_name,
-               cc.hypertable_constraint_name AS new_name
+               CASE WHEN parent.contype = 'f' THEN cc.hypertable_constraint_name
+                    ELSE format('%s_%s', c.id, cc.hypertable_constraint_name)
+               END AS new_name
         FROM _timescaledb_catalog.chunk_constraint cc
         JOIN _timescaledb_catalog.chunk c ON c.id = cc.chunk_id
         JOIN _timescaledb_catalog.hypertable ht ON ht.id = c.hypertable_id
         JOIN pg_constraint parent
             ON parent.conrelid = pg_catalog.format('%I.%I', ht.schema_name, ht.table_name)::regclass
             AND parent.conname = cc.hypertable_constraint_name
-            AND parent.contype = 'f'
+            AND parent.contype IN ('f', 'u', 'p', 'x', 't')
         WHERE cc.dimension_slice_id IS NULL
           AND cc.hypertable_constraint_name IS NOT NULL
-          AND cc.constraint_name <> cc.hypertable_constraint_name
     LOOP
-        EXECUTE pg_catalog.format('ALTER TABLE %s RENAME CONSTRAINT %I TO %I',
-                                  r.chunk_table, r.old_name, r.new_name);
+        IF r.old_name <> r.new_name THEN
+            EXECUTE pg_catalog.format('ALTER TABLE %s RENAME CONSTRAINT %I TO %I',
+                                      r.chunk_table, r.old_name, r.new_name);
+        END IF;
     END LOOP;
 END
 $$;
 
--- Drop the obsolete chunk_constraint rows for outbound FKs; the event-trigger
--- hooks locate chunk-side FKs by name and no longer need this catalog.
-DELETE FROM _timescaledb_catalog.chunk_constraint cc
-USING _timescaledb_catalog.chunk c,
-      _timescaledb_catalog.hypertable ht,
-      pg_constraint parent
-WHERE cc.chunk_id = c.id
-  AND ht.id = c.hypertable_id
-  AND parent.conrelid = pg_catalog.format('%I.%I', ht.schema_name, ht.table_name)::regclass
-  AND parent.conname = cc.hypertable_constraint_name
-  AND parent.contype = 'f'
-  AND cc.dimension_slice_id IS NULL
-  AND cc.hypertable_constraint_name IS NOT NULL;
+-- Remove the chunk_constraint rows that mirrored non-dimensional constraints.
+-- FK chunk-side constraints are now located by name through the event-trigger
+-- hooks; unique/PK/exclusion/trigger constraints through the deterministic
+-- "<chunk_id>_<parent>" name pattern.
+DELETE FROM _timescaledb_catalog.chunk_constraint
+WHERE dimension_slice_id IS NULL
+  AND hypertable_constraint_name IS NOT NULL;
 
---
--- Include the `hypertable` and the `chunk` catalog tables in the historical
--- snapshot during logical replication
---
 ALTER TABLE _timescaledb_catalog.hypertable SET (user_catalog_table = true);
 ALTER TABLE _timescaledb_catalog.chunk SET (user_catalog_table = true);
+

sql/updates/reverse-dev.sql

@@ -26,5 +26,21 @@ JOIN pg_constraint child
     AND child.conname = parent.conname
 ON CONFLICT DO NOTHING;
 
+-- Restore chunk_constraint rows for unique/PK/exclusion/trigger constraints.
+-- The chunk-side conname is the deterministic "<chunk_id>_<parent>" form
+INSERT INTO _timescaledb_catalog.chunk_constraint
+    (chunk_id, dimension_slice_id, constraint_name, hypertable_constraint_name)
+SELECT c.id, NULL, child.conname, parent.conname
+FROM _timescaledb_catalog.chunk c
+JOIN _timescaledb_catalog.hypertable ht ON ht.id = c.hypertable_id
+JOIN pg_constraint parent
+    ON parent.conrelid = pg_catalog.format('%I.%I', ht.schema_name, ht.table_name)::regclass
+    AND parent.contype IN ('u', 'p', 'x', 't')
+JOIN pg_constraint child
+    ON child.conrelid = pg_catalog.format('%I.%I', c.schema_name, c.table_name)::regclass
+    AND child.conname = format('%s_%s', c.id, parent.conname)
+ON CONFLICT DO NOTHING;
+
 ALTER TABLE _timescaledb_catalog.hypertable RESET (user_catalog_table);
 ALTER TABLE _timescaledb_catalog.chunk RESET (user_catalog_table);
+

src/chunk.c

@@ -3218,11 +3218,11 @@ chunk_tuple_delete(TupleInfo *ti, Oid relid, DropBehavior behavior, bool detach)
 	}
 
 	/*
-	 * Even tough we keep foreign key constraints on the chunk, we still
-	 * need to drop the referencing foreign keys since such keys are possibly
-	 * intended to reference the hypertable, not the chunk.
+	 * Drop FKs that reference this chunk. They target the chunk's PK index
+	 * directly, so without explicit removal the index would block the chunk
+	 * drop. Skip when the relation is already gone (cascade from hypertable).
 	 */
-	if (detach)
+	if (detach && OidIsValid(relid) && SearchSysCacheExists1(RELOID, ObjectIdGetDatum(relid)))
 	{
 		ts_chunk_drop_referencing_fk_by_chunk_id(form.id);
 	}