Fix cloning of row triggers to sub-partitions

When row triggers exist in partitioned partitions that are not either
part of FKs or deferred unique constraints, they are not correctly
cloned to their partitions.  That's because they are marked "internal",
and those are purposefully skipped when doing the clone triggers dance.
Fix by relaxing the condition on which internal triggers are skipped.

Amit Langote initially diagnosed the problem and proposed a fix, but I
used a different approach.

Reported-by: Petr Fedorov
Discussion: https://postgr.es/m/6b3f0646-ba8c-b3a9-c62d-1c6651a1920f@phystech.edu

diff --git a/src/backend/commands/tablecmds.c b/src/backend/commands/tablecmds.c
index 01bc292ada0bcb8c53ea1203ae01d892b355a98d..1c4394abea159bae01257c517bc194c672ed6038 100644 (file)
--- a/src/backend/commands/tablecmds.c
+++ b/src/backend/commands/tablecmds.c
@@ -15931,6 +15931,54 @@ out:
    MemoryContextDelete(cxt);
 }
 
+/*
+ * isPartitionTrigger
+ *     Subroutine for CloneRowTriggersToPartition: determine whether
+ *     the given trigger has been cloned from another one.
+ *
+ * We use pg_depend as a proxy for this, since we don't have any direct
+ * evidence.  This is an ugly hack to cope with a catalog deficiency.
+ * Keep away from children.  Do not stare with naked eyes.  Do not propagate.
+ */
+static bool
+isPartitionTrigger(Oid trigger_oid)
+{
+   Relation    pg_depend;
+   ScanKeyData key[2];
+   SysScanDesc scan;
+   HeapTuple   tup;
+   bool        found = false;
+
+   pg_depend = table_open(DependRelationId, AccessShareLock);
+
+   ScanKeyInit(&key[0], Anum_pg_depend_classid,
+               BTEqualStrategyNumber,
+               F_OIDEQ,
+               ObjectIdGetDatum(TriggerRelationId));
+   ScanKeyInit(&key[1], Anum_pg_depend_objid,
+               BTEqualStrategyNumber,
+               F_OIDEQ,
+               ObjectIdGetDatum(trigger_oid));
+
+   scan = systable_beginscan(pg_depend, DependDependerIndexId,
+                             true, NULL, 2, key);
+   while ((tup = systable_getnext(scan)) != NULL)
+   {
+       Form_pg_depend  dep = (Form_pg_depend) GETSTRUCT(tup);
+
+       if (dep->refclassid == TriggerRelationId)
+       {
+           found = true;
+           break;
+       }
+   }
+
+   systable_endscan(scan);
+   table_close(pg_depend, AccessShareLock);
+
+   return found;
+}
+
 /*
  * CloneRowTriggersToPartition
  *     subroutine for ATExecAttachPartition/DefineRelation to create row
@@ -15971,8 +16019,21 @@ CloneRowTriggersToPartition(Relation parent, Relation partition)
        if (!TRIGGER_FOR_ROW(trigForm->tgtype))
            continue;
 
-       /* We don't clone internal triggers, either */
-       if (trigForm->tgisinternal)
+       /*
+        * Internal triggers require careful examination.  Ideally, we don't
+        * clone them.
+        *
+        * However, if our parent is a partitioned relation, there might be
+        * internal triggers that need cloning.  In that case, we must
+        * skip clone it if the trigger on parent depends on another trigger.
+        *
+        * Note we dare not verify that the other trigger belongs to an
+        * ancestor relation of our parent, because that creates deadlock
+        * opportunities.
+        */
+       if (trigForm->tgisinternal &&
+           (!parent->rd_rel->relispartition ||
+            !isPartitionTrigger(trigForm->oid)))
            continue;
 
        /*

diff --git a/src/test/regress/expected/triggers.out b/src/test/regress/expected/triggers.out
index 1e4053ceed9b8ab716f1790514185a4b335aa0c2..b91fbd0648162becb1e77fbc4049762faf714dbb 100644 (file)
--- a/src/test/regress/expected/triggers.out
+++ b/src/test/regress/expected/triggers.out
@@ -1981,15 +1981,22 @@ create trigger trg1 after insert on trigpart for each row execute procedure trig
 create table trigpart2 partition of trigpart for values from (1000) to (2000);
 create table trigpart3 (like trigpart);
 alter table trigpart attach partition trigpart3 for values from (2000) to (3000);
+create table trigpart4 partition of trigpart for values from (3000) to (4000) partition by range (a);
+create table trigpart41 partition of trigpart4 for values from (3000) to (3500);
+create table trigpart42 (like trigpart);
+alter table trigpart4 attach partition trigpart42 for values from (3500) to (4000);
 select tgrelid::regclass, tgname, tgfoid::regproc from pg_trigger
   where tgrelid::regclass::text like 'trigpart%' order by tgrelid::regclass::text;
-  tgrelid  | tgname |     tgfoid      
------------+--------+-----------------
- trigpart  | trg1   | trigger_nothing
- trigpart1 | trg1   | trigger_nothing
- trigpart2 | trg1   | trigger_nothing
- trigpart3 | trg1   | trigger_nothing
-(4 rows)
+  tgrelid   | tgname |     tgfoid      
+------------+--------+-----------------
+ trigpart   | trg1   | trigger_nothing
+ trigpart1  | trg1   | trigger_nothing
+ trigpart2  | trg1   | trigger_nothing
+ trigpart3  | trg1   | trigger_nothing
+ trigpart4  | trg1   | trigger_nothing
+ trigpart41 | trg1   | trigger_nothing
+ trigpart42 | trg1   | trigger_nothing
+(7 rows)
 
 drop trigger trg1 on trigpart1;    -- fail
 ERROR:  cannot drop trigger trg1 on table trigpart1 because trigger trg1 on table trigpart requires it
@@ -2003,12 +2010,15 @@ HINT:  You can drop trigger trg1 on table trigpart instead.
 drop table trigpart2;          -- ok, trigger should be gone in that partition
 select tgrelid::regclass, tgname, tgfoid::regproc from pg_trigger
   where tgrelid::regclass::text like 'trigpart%' order by tgrelid::regclass::text;
-  tgrelid  | tgname |     tgfoid      
------------+--------+-----------------
- trigpart  | trg1   | trigger_nothing
- trigpart1 | trg1   | trigger_nothing
- trigpart3 | trg1   | trigger_nothing
-(3 rows)
+  tgrelid   | tgname |     tgfoid      
+------------+--------+-----------------
+ trigpart   | trg1   | trigger_nothing
+ trigpart1  | trg1   | trigger_nothing
+ trigpart3  | trg1   | trigger_nothing
+ trigpart4  | trg1   | trigger_nothing
+ trigpart41 | trg1   | trigger_nothing
+ trigpart42 | trg1   | trigger_nothing
+(6 rows)
 
 drop trigger trg1 on trigpart;     -- ok, all gone
 select tgrelid::regclass, tgname, tgfoid::regproc from pg_trigger

diff --git a/src/test/regress/sql/triggers.sql b/src/test/regress/sql/triggers.sql
index c21b6c124e0972d344aad3e32aa552f6f277b87d..7cd835449c5f960437542d1143b1da44dbef049d 100644 (file)
--- a/src/test/regress/sql/triggers.sql
+++ b/src/test/regress/sql/triggers.sql
@@ -1366,6 +1366,10 @@ create trigger trg1 after insert on trigpart for each row execute procedure trig
 create table trigpart2 partition of trigpart for values from (1000) to (2000);
 create table trigpart3 (like trigpart);
 alter table trigpart attach partition trigpart3 for values from (2000) to (3000);
+create table trigpart4 partition of trigpart for values from (3000) to (4000) partition by range (a);
+create table trigpart41 partition of trigpart4 for values from (3000) to (3500);
+create table trigpart42 (like trigpart);
+alter table trigpart4 attach partition trigpart42 for values from (3500) to (4000);
 select tgrelid::regclass, tgname, tgfoid::regproc from pg_trigger
   where tgrelid::regclass::text like 'trigpart%' order by tgrelid::regclass::text;
 drop trigger trg1 on trigpart1;    -- fail