From 52443a469a58d3f64a4e049889f468e8a149cc8f Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Fabr=C3=ADzio=20de=20Royes=20Mello?=
 <fabriziomello@gmail.com>
Date: Thu, 2 May 2024 15:52:32 -0300
Subject: [PATCH] Fix hypertable foreign keys for 2.15.X

---
 utils/2.15.X-fix_hypertable_foreign_keys.sql | 78 ++++++++++++++++++++
 1 file changed, 78 insertions(+)
 create mode 100644 utils/2.15.X-fix_hypertable_foreign_keys.sql

diff --git a/utils/2.15.X-fix_hypertable_foreign_keys.sql b/utils/2.15.X-fix_hypertable_foreign_keys.sql
new file mode 100644
index 0000000..8c3726a
--- /dev/null
+++ b/utils/2.15.X-fix_hypertable_foreign_keys.sql
@@ -0,0 +1,78 @@
+-- Fix compressed hypertables with FOREIGN KEY constraints that were created with TimescaleDB versions before 2.15.0
+CREATE OR REPLACE FUNCTION pg_temp.constraint_columns(regclass, int2[]) RETURNS text[] AS
+$$
+  SELECT array_agg(attname) FROM unnest($2) un(attnum) LEFT JOIN pg_attribute att ON att.attrelid=$1 AND att.attnum = un.attnum;
+$$ LANGUAGE SQL SET search_path TO pg_catalog, pg_temp;
+
+DO $$
+DECLARE
+  ht_id int;
+  ht regclass;
+  chunk regclass;
+  con_oid oid;
+  con_frelid regclass;
+  con_name text;
+  con_columns text[];
+  chunk_id int;
+
+BEGIN
+
+  -- iterate over all hypertables that have foreign key constraints
+  FOR ht_id, ht in
+    SELECT
+      ht.id,
+      format('%I.%I',ht.schema_name,ht.table_name)::regclass
+    FROM _timescaledb_catalog.hypertable ht
+    WHERE
+      EXISTS (
+        SELECT FROM pg_constraint con
+        WHERE
+          con.contype='f' AND
+          con.conrelid=format('%I.%I',ht.schema_name,ht.table_name)::regclass
+      )
+  LOOP
+    RAISE NOTICE 'Hypertable % has foreign key constraint', ht;
+
+    -- iterate over all foreign key constraints on the hypertable
+    -- and check that they are present on every chunk
+    FOR con_oid, con_frelid, con_name, con_columns IN
+      SELECT con.oid, con.confrelid, con.conname, pg_temp.constraint_columns(con.conrelid,con.conkey)
+      FROM pg_constraint con
+      WHERE
+        con.contype='f' AND
+        con.conrelid=ht
+    LOOP
+      RAISE NOTICE 'Checking constraint % %', con_name, con_columns;
+      -- check that the foreign key constraint is present on the chunk
+
+      FOR chunk_id, chunk IN
+        SELECT
+          ch.id,
+          format('%I.%I',ch.schema_name,ch.table_name)::regclass
+        FROM _timescaledb_catalog.chunk ch
+        WHERE
+          ch.hypertable_id=ht_id
+      LOOP
+        RAISE NOTICE 'Checking chunk %', chunk;
+        IF NOT EXISTS (
+          SELECT FROM pg_constraint con
+          WHERE
+            con.contype='f' AND
+            con.conrelid=chunk AND
+            con.confrelid=con_frelid  AND
+            pg_temp.constraint_columns(con.conrelid,con.conkey) = con_columns
+        ) THEN
+          RAISE WARNING 'Restoring constraint % on chunk %', con_name, chunk;
+          PERFORM _timescaledb_functions.constraint_clone(con_oid, chunk);
+          INSERT INTO _timescaledb_catalog.chunk_constraint(chunk_id, dimension_slice_id, constraint_name, hypertable_constraint_name) VALUES (chunk_id, NULL, con_name, con_name);
+        END IF;
+
+      END LOOP;
+    END LOOP;
+
+  END LOOP;
+
+END
+$$;
+
+DROP FUNCTION pg_temp.constraint_columns(regclass, int2[]);