Fix trigger transition table capture for MERGE in CTE queries.

When executing a data-modifying CTE query containing MERGE and some
other DML operation on a table with statement-level AFTER triggers,
the transition tables passed to the triggers would fail to include the
rows affected by the MERGE.

The reason is that, when initializing a ModifyTable node for MERGE,
MakeTransitionCaptureState() would create a TransitionCaptureState
structure with a single "tcs_private" field pointing to an
AfterTriggersTableData structure with cmdType == CMD_MERGE. Tuples
captured there would then not be included in the sets of tuples
captured when executing INSERT/UPDATE/DELETE ModifyTable nodes in the
same query.

Since there are no MERGE triggers, we should only create
AfterTriggersTableData structures for INSERT/UPDATE/DELETE. Individual
MERGE actions should then use those, thereby sharing the same capture
tuplestores as any other DML commands executed in the same query.

This requires changing the TransitionCaptureState structure, replacing
"tcs_private" with 3 separate pointers to AfterTriggersTableData
structures, one for each of INSERT, UPDATE, and DELETE. Nominally,
this is an ABI break to a public structure in commands/trigger.h.
However, since this is a private field pointing to an opaque data
structure, the only way to create a valid TransitionCaptureState is by
calling MakeTransitionCaptureState(), and no extensions appear to be
doing that anyway, so it seems safe for back-patching.

Backpatch to v15, where MERGE was introduced.

Bug: #19380
Reported-by: Daniel Woelfel <dwwoelfel@gmail.com>
Author: Dean Rasheed <dean.a.rasheed@gmail.com>
Reviewed-by: Tom Lane <tgl@sss.pgh.pa.us>
Discussion: https://postgr.es/m/19380-4e293be2b4007248%40postgresql.org
Backpatch-through: 15

diff --git a/src/backend/commands/trigger.c b/src/backend/commands/trigger.c
index d30fda660ebc998aceb251ccd03b7e533bc19f22..8df915f63fb997b3f2f9bba6b89b978b07600152 100644 (file)
--- a/src/backend/commands/trigger.c
+++ b/src/backend/commands/trigger.c
@@ -3919,21 +3919,10 @@ struct AfterTriggersTableData
        bool            after_trig_done;        /* did we already queue AS triggers? */
        AfterTriggerEventList after_trig_events;        /* if so, saved list pointer */
 
-       /*
-        * We maintain separate transition tables for UPDATE/INSERT/DELETE since
-        * MERGE can run all three actions in a single statement. Note that UPDATE
-        * needs both old and new transition tables whereas INSERT needs only new,
-        * and DELETE needs only old.
-        */
-
-       /* "old" transition table for UPDATE, if any */
-       Tuplestorestate *old_upd_tuplestore;
-       /* "new" transition table for UPDATE, if any */
-       Tuplestorestate *new_upd_tuplestore;
-       /* "old" transition table for DELETE, if any */
-       Tuplestorestate *old_del_tuplestore;
-       /* "new" transition table for INSERT, if any */
-       Tuplestorestate *new_ins_tuplestore;
+       /* "old" transition table for UPDATE/DELETE, if any */
+       Tuplestorestate *old_tuplestore;
+       /* "new" transition table for INSERT/UPDATE, if any */
+       Tuplestorestate *new_tuplestore;
 
        TupleTableSlot *storeslot;      /* for converting to tuplestore's format */
 };
@@ -3960,6 +3949,7 @@ static Tuplestorestate *GetAfterTriggersTransitionTable(int event,
                                                                                                                TupleTableSlot *newslot,
                                                                                                                TransitionCaptureState *transition_capture);
 static void TransitionTableAddTuple(EState *estate,
+                                                                       int event,
                                                                        TransitionCaptureState *transition_capture,
                                                                        ResultRelInfo *relinfo,
                                                                        TupleTableSlot *slot,
@@ -4527,19 +4517,13 @@ AfterTriggerExecute(EState *estate,
        {
                if (LocTriggerData.tg_trigger->tgoldtable)
                {
-                       if (TRIGGER_FIRED_BY_UPDATE(evtshared->ats_event))
-                               LocTriggerData.tg_oldtable = evtshared->ats_table->old_upd_tuplestore;
-                       else
-                               LocTriggerData.tg_oldtable = evtshared->ats_table->old_del_tuplestore;
+                       LocTriggerData.tg_oldtable = evtshared->ats_table->old_tuplestore;
                        evtshared->ats_table->closed = true;
                }
 
                if (LocTriggerData.tg_trigger->tgnewtable)
                {
-                       if (TRIGGER_FIRED_BY_INSERT(evtshared->ats_event))
-                               LocTriggerData.tg_newtable = evtshared->ats_table->new_ins_tuplestore;
-                       else
-                               LocTriggerData.tg_newtable = evtshared->ats_table->new_upd_tuplestore;
+                       LocTriggerData.tg_newtable = evtshared->ats_table->new_tuplestore;
                        evtshared->ats_table->closed = true;
                }
        }
@@ -4886,6 +4870,11 @@ GetAfterTriggersTableData(Oid relid, CmdType cmdType)
        MemoryContext oldcxt;
        ListCell   *lc;
 
+       /* At this level, cmdType should not be, eg, CMD_MERGE */
+       Assert(cmdType == CMD_INSERT ||
+                  cmdType == CMD_UPDATE ||
+                  cmdType == CMD_DELETE);
+
        /* Caller should have ensured query_depth is OK. */
        Assert(afterTriggers.query_depth >= 0 &&
                   afterTriggers.query_depth < afterTriggers.maxquerydepth);
@@ -4972,7 +4961,9 @@ MakeTransitionCaptureState(TriggerDesc *trigdesc, Oid relid, CmdType cmdType)
                                need_new_upd,
                                need_old_del,
                                need_new_ins;
-       AfterTriggersTableData *table;
+       AfterTriggersTableData *ins_table;
+       AfterTriggersTableData *upd_table;
+       AfterTriggersTableData *del_table;
        MemoryContext oldcxt;
        ResourceOwner saveResourceOwner;
 
@@ -5019,10 +5010,15 @@ MakeTransitionCaptureState(TriggerDesc *trigdesc, Oid relid, CmdType cmdType)
                AfterTriggerEnlargeQueryState();
 
        /*
-        * Find or create an AfterTriggersTableData struct to hold the
+        * Find or create AfterTriggersTableData struct(s) to hold the
         * tuplestore(s).  If there's a matching struct but it's marked closed,
         * ignore it; we need a newer one.
         *
+        * Note: MERGE must use the same AfterTriggersTableData structs as INSERT,
+        * UPDATE, and DELETE, so that any MERGE'd tuples are added to the same
+        * tuplestores as tuples from any INSERT, UPDATE, or DELETE commands
+        * running in the same top-level command (e.g., in a writable CTE).
+        *
         * Note: the AfterTriggersTableData list, as well as the tuplestores, are
         * allocated in the current (sub)transaction's CurTransactionContext, and
         * the tuplestores are managed by the (sub)transaction's resource owner.
@@ -5030,21 +5026,34 @@ MakeTransitionCaptureState(TriggerDesc *trigdesc, Oid relid, CmdType cmdType)
         * transition tables to be deferrable; they will be fired during
         * AfterTriggerEndQuery, after which it's okay to delete the data.
         */
-       table = GetAfterTriggersTableData(relid, cmdType);
+       if (need_new_ins)
+               ins_table = GetAfterTriggersTableData(relid, CMD_INSERT);
+       else
+               ins_table = NULL;
+
+       if (need_old_upd || need_new_upd)
+               upd_table = GetAfterTriggersTableData(relid, CMD_UPDATE);
+       else
+               upd_table = NULL;
+
+       if (need_old_del)
+               del_table = GetAfterTriggersTableData(relid, CMD_DELETE);
+       else
+               del_table = NULL;
 
        /* Now create required tuplestore(s), if we don't have them already. */
        oldcxt = MemoryContextSwitchTo(CurTransactionContext);
        saveResourceOwner = CurrentResourceOwner;
        CurrentResourceOwner = CurTransactionResourceOwner;
 
-       if (need_old_upd && table->old_upd_tuplestore == NULL)
-               table->old_upd_tuplestore = tuplestore_begin_heap(false, false, work_mem);
-       if (need_new_upd && table->new_upd_tuplestore == NULL)
-               table->new_upd_tuplestore = tuplestore_begin_heap(false, false, work_mem);
-       if (need_old_del && table->old_del_tuplestore == NULL)
-               table->old_del_tuplestore = tuplestore_begin_heap(false, false, work_mem);
-       if (need_new_ins && table->new_ins_tuplestore == NULL)
-               table->new_ins_tuplestore = tuplestore_begin_heap(false, false, work_mem);
+       if (need_old_upd && upd_table->old_tuplestore == NULL)
+               upd_table->old_tuplestore = tuplestore_begin_heap(false, false, work_mem);
+       if (need_new_upd && upd_table->new_tuplestore == NULL)
+               upd_table->new_tuplestore = tuplestore_begin_heap(false, false, work_mem);
+       if (need_old_del && del_table->old_tuplestore == NULL)
+               del_table->old_tuplestore = tuplestore_begin_heap(false, false, work_mem);
+       if (need_new_ins && ins_table->new_tuplestore == NULL)
+               ins_table->new_tuplestore = tuplestore_begin_heap(false, false, work_mem);
 
        CurrentResourceOwner = saveResourceOwner;
        MemoryContextSwitchTo(oldcxt);
@@ -5055,7 +5064,9 @@ MakeTransitionCaptureState(TriggerDesc *trigdesc, Oid relid, CmdType cmdType)
        state->tcs_update_old_table = need_old_upd;
        state->tcs_update_new_table = need_new_upd;
        state->tcs_insert_new_table = need_new_ins;
-       state->tcs_private = table;
+       state->tcs_insert_private = ins_table;
+       state->tcs_update_private = upd_table;
+       state->tcs_delete_private = del_table;
 
        return state;
 }
@@ -5233,20 +5244,12 @@ AfterTriggerFreeQuery(AfterTriggersQueryData *qs)
        {
                AfterTriggersTableData *table = (AfterTriggersTableData *) lfirst(lc);
 
-               ts = table->old_upd_tuplestore;
-               table->old_upd_tuplestore = NULL;
-               if (ts)
-                       tuplestore_end(ts);
-               ts = table->new_upd_tuplestore;
-               table->new_upd_tuplestore = NULL;
-               if (ts)
-                       tuplestore_end(ts);
-               ts = table->old_del_tuplestore;
-               table->old_del_tuplestore = NULL;
+               ts = table->old_tuplestore;
+               table->old_tuplestore = NULL;
                if (ts)
                        tuplestore_end(ts);
-               ts = table->new_ins_tuplestore;
-               table->new_ins_tuplestore = NULL;
+               ts = table->new_tuplestore;
+               table->new_tuplestore = NULL;
                if (ts)
                        tuplestore_end(ts);
                if (table->storeslot)
@@ -5557,17 +5560,17 @@ GetAfterTriggersTransitionTable(int event,
        {
                Assert(TupIsNull(newslot));
                if (event == TRIGGER_EVENT_DELETE && delete_old_table)
-                       tuplestore = transition_capture->tcs_private->old_del_tuplestore;
+                       tuplestore = transition_capture->tcs_delete_private->old_tuplestore;
                else if (event == TRIGGER_EVENT_UPDATE && update_old_table)
-                       tuplestore = transition_capture->tcs_private->old_upd_tuplestore;
+                       tuplestore = transition_capture->tcs_update_private->old_tuplestore;
        }
        else if (!TupIsNull(newslot))
        {
                Assert(TupIsNull(oldslot));
                if (event == TRIGGER_EVENT_INSERT && insert_new_table)
-                       tuplestore = transition_capture->tcs_private->new_ins_tuplestore;
+                       tuplestore = transition_capture->tcs_insert_private->new_tuplestore;
                else if (event == TRIGGER_EVENT_UPDATE && update_new_table)
-                       tuplestore = transition_capture->tcs_private->new_upd_tuplestore;
+                       tuplestore = transition_capture->tcs_update_private->new_tuplestore;
        }
 
        return tuplestore;
@@ -5581,6 +5584,7 @@ GetAfterTriggersTransitionTable(int event,
  */
 static void
 TransitionTableAddTuple(EState *estate,
+                                               int event,
                                                TransitionCaptureState *transition_capture,
                                                ResultRelInfo *relinfo,
                                                TupleTableSlot *slot,
@@ -5599,9 +5603,26 @@ TransitionTableAddTuple(EState *estate,
                tuplestore_puttupleslot(tuplestore, original_insert_tuple);
        else if ((map = ExecGetChildToRootMap(relinfo)) != NULL)
        {
-               AfterTriggersTableData *table = transition_capture->tcs_private;
+               AfterTriggersTableData *table;
                TupleTableSlot *storeslot;
 
+               switch (event)
+               {
+                       case TRIGGER_EVENT_INSERT:
+                               table = transition_capture->tcs_insert_private;
+                               break;
+                       case TRIGGER_EVENT_UPDATE:
+                               table = transition_capture->tcs_update_private;
+                               break;
+                       case TRIGGER_EVENT_DELETE:
+                               table = transition_capture->tcs_delete_private;
+                               break;
+                       default:
+                               elog(ERROR, "invalid after-trigger event code: %d", event);
+                               table = NULL;   /* keep compiler quiet */
+                               break;
+               }
+
                storeslot = GetAfterTriggersStoreSlot(table, map->outdesc);
                execute_attr_map_slot(map->attrMap, slot, storeslot);
                tuplestore_puttupleslot(tuplestore, storeslot);
@@ -6195,7 +6216,7 @@ AfterTriggerSaveEvent(EState *estate, ResultRelInfo *relinfo,
                                                                                                                         oldslot,
                                                                                                                         NULL,
                                                                                                                         transition_capture);
-                       TransitionTableAddTuple(estate, transition_capture, relinfo,
+                       TransitionTableAddTuple(estate, event, transition_capture, relinfo,
                                                                        oldslot, NULL, old_tuplestore);
                }
 
@@ -6211,7 +6232,7 @@ AfterTriggerSaveEvent(EState *estate, ResultRelInfo *relinfo,
                                                                                                                         NULL,
                                                                                                                         newslot,
                                                                                                                         transition_capture);
-                       TransitionTableAddTuple(estate, transition_capture, relinfo,
+                       TransitionTableAddTuple(estate, event, transition_capture, relinfo,
                                                                        newslot, original_insert_tuple, new_tuplestore);
                }
 
@@ -6514,7 +6535,24 @@ AfterTriggerSaveEvent(EState *estate, ResultRelInfo *relinfo,
                new_shared.ats_firing_id = 0;
                if ((trigger->tgoldtable || trigger->tgnewtable) &&
                        transition_capture != NULL)
-                       new_shared.ats_table = transition_capture->tcs_private;
+               {
+                       switch (event)
+                       {
+                               case TRIGGER_EVENT_INSERT:
+                                       new_shared.ats_table = transition_capture->tcs_insert_private;
+                                       break;
+                               case TRIGGER_EVENT_UPDATE:
+                                       new_shared.ats_table = transition_capture->tcs_update_private;
+                                       break;
+                               case TRIGGER_EVENT_DELETE:
+                                       new_shared.ats_table = transition_capture->tcs_delete_private;
+                                       break;
+                               default:
+                                       /* Must be TRUNCATE, see switch above */
+                                       new_shared.ats_table = NULL;
+                                       break;
+                       }
+               }
                else
                        new_shared.ats_table = NULL;
                new_shared.ats_modifiedcols = modifiedCols;

diff --git a/src/include/commands/trigger.h b/src/include/commands/trigger.h
index b60317c7a759c04dc0f6ed6bd8dc386e137fc0f5..556c86bf5e1744fa55743956407f0645f1f0da2f 100644 (file)
--- a/src/include/commands/trigger.h
+++ b/src/include/commands/trigger.h
@@ -78,7 +78,9 @@ typedef struct TransitionCaptureState
        /*
         * Private data including the tuplestore(s) into which to insert tuples.
         */
-       struct AfterTriggersTableData *tcs_private;
+       struct AfterTriggersTableData *tcs_insert_private;
+       struct AfterTriggersTableData *tcs_update_private;
+       struct AfterTriggersTableData *tcs_delete_private;
 } TransitionCaptureState;
 
 /*

diff --git a/src/test/regress/expected/triggers.out b/src/test/regress/expected/triggers.out
index 1eb8fba0953706999187bc7fce7d5a36eb9d108b..1acdd12d29eaa19cc27018d8a7e8263a257f1518 100644 (file)
--- a/src/test/regress/expected/triggers.out
+++ b/src/test/regress/expected/triggers.out
@@ -3033,13 +3033,19 @@ NOTICE:  trigger = table1_trig, new table = (42)
 with wcte as (insert into table1 values (43))
   insert into table1 values (44);
 NOTICE:  trigger = table1_trig, new table = (43), (44)
+with wcte as (insert into table1 values (45))
+  merge into table1 using (values (46)) as v(a) on table1.a = v.a
+    when not matched then insert values (v.a);
+NOTICE:  trigger = table1_trig, new table = (45), (46)
 select * from table1;
  a  
 ----
  42
  44
  43
-(3 rows)
+ 46
+ 45
+(5 rows)
 
 select * from table2;
       a      

diff --git a/src/test/regress/sql/triggers.sql b/src/test/regress/sql/triggers.sql
index 5f7f75d7ba5d9169e15f118f3ac37948ac230177..cc878455ace910cdc1374f1745a3669edad3cacf 100644 (file)
--- a/src/test/regress/sql/triggers.sql
+++ b/src/test/regress/sql/triggers.sql
@@ -2228,6 +2228,10 @@ with wcte as (insert into table1 values (42))
 with wcte as (insert into table1 values (43))
   insert into table1 values (44);
 
+with wcte as (insert into table1 values (45))
+  merge into table1 using (values (46)) as v(a) on table1.a = v.a
+    when not matched then insert values (v.a);
+
 select * from table1;
 select * from table2;