Fix handling of multiple AFTER ROW triggers on a foreign table.

AfterTriggerExecute() retrieves a fresh tuple or pair of tuples from a
tuplestore and then stores the tuple(s) in the passed-in slot(s) if
AFTER_TRIGGER_FDW_FETCH, while it uses the most-recently-retrieved
tuple(s) stored in the slot(s) if AFTER_TRIGGER_FDW_REUSE.  This was
done correctly before 12, but commit ff11e7f4b broke it by mistakenly
clearing the tuple(s) stored in the slot(s) in that function, leading to
an assertion failure as reported in bug #16139 from Alexander Lakhin.

Also, fix some other issues with the aforementioned commit in passing:

* For tg_newslot, which is a slot added to the TriggerData struct by the
  commit to store new updated tuples, it didn't ensure the slot was NULL
  if there was no such tuple.
* The commit failed to update the documentation about the trigger
  interface.

Author: Etsuro Fujita
Backpatch-through: 12
Discussion: https://postgr.es/m/16139-94f9ccf0db6119ec%40postgresql.org
This commit is contained in:
Etsuro Fujita 2019-12-10 18:00:31 +09:00
parent 001362cfdc
commit 547e454cbc
4 changed files with 81 additions and 24 deletions

View File

@ -6459,6 +6459,36 @@ DROP TRIGGER trig_row_after ON rem1;
DROP TRIGGER trig_stmt_before ON rem1;
DROP TRIGGER trig_stmt_after ON rem1;
DELETE from rem1;
-- Test multiple AFTER ROW triggers on a foreign table
CREATE TRIGGER trig_row_after1
AFTER INSERT OR UPDATE OR DELETE ON rem1
FOR EACH ROW EXECUTE PROCEDURE trigger_data(23,'skidoo');
CREATE TRIGGER trig_row_after2
AFTER INSERT OR UPDATE OR DELETE ON rem1
FOR EACH ROW EXECUTE PROCEDURE trigger_data(23,'skidoo');
insert into rem1 values(1,'insert');
NOTICE: trig_row_after1(23, skidoo) AFTER ROW INSERT ON rem1
NOTICE: NEW: (1,insert)
NOTICE: trig_row_after2(23, skidoo) AFTER ROW INSERT ON rem1
NOTICE: NEW: (1,insert)
update rem1 set f2 = 'update' where f1 = 1;
NOTICE: trig_row_after1(23, skidoo) AFTER ROW UPDATE ON rem1
NOTICE: OLD: (1,insert),NEW: (1,update)
NOTICE: trig_row_after2(23, skidoo) AFTER ROW UPDATE ON rem1
NOTICE: OLD: (1,insert),NEW: (1,update)
update rem1 set f2 = f2 || f2;
NOTICE: trig_row_after1(23, skidoo) AFTER ROW UPDATE ON rem1
NOTICE: OLD: (1,update),NEW: (1,updateupdate)
NOTICE: trig_row_after2(23, skidoo) AFTER ROW UPDATE ON rem1
NOTICE: OLD: (1,update),NEW: (1,updateupdate)
delete from rem1;
NOTICE: trig_row_after1(23, skidoo) AFTER ROW DELETE ON rem1
NOTICE: OLD: (1,updateupdate)
NOTICE: trig_row_after2(23, skidoo) AFTER ROW DELETE ON rem1
NOTICE: OLD: (1,updateupdate)
-- cleanup
DROP TRIGGER trig_row_after1 ON rem1;
DROP TRIGGER trig_row_after2 ON rem1;
-- Test WHEN conditions
CREATE TRIGGER trig_row_before_insupd
BEFORE INSERT OR UPDATE ON rem1
@ -6689,7 +6719,7 @@ NOTICE: trig_row_after(23, skidoo) AFTER ROW INSERT ON rem1
NOTICE: NEW: (13,"test triggered !")
ctid
--------
(0,29)
(0,32)
(1 row)
-- cleanup

View File

@ -1485,6 +1485,23 @@ DROP TRIGGER trig_stmt_after ON rem1;
DELETE from rem1;
-- Test multiple AFTER ROW triggers on a foreign table
CREATE TRIGGER trig_row_after1
AFTER INSERT OR UPDATE OR DELETE ON rem1
FOR EACH ROW EXECUTE PROCEDURE trigger_data(23,'skidoo');
CREATE TRIGGER trig_row_after2
AFTER INSERT OR UPDATE OR DELETE ON rem1
FOR EACH ROW EXECUTE PROCEDURE trigger_data(23,'skidoo');
insert into rem1 values(1,'insert');
update rem1 set f2 = 'update' where f1 = 1;
update rem1 set f2 = f2 || f2;
delete from rem1;
-- cleanup
DROP TRIGGER trig_row_after1 ON rem1;
DROP TRIGGER trig_row_after2 ON rem1;
-- Test WHEN conditions

View File

@ -511,8 +511,8 @@ typedef struct TriggerData
HeapTuple tg_trigtuple;
HeapTuple tg_newtuple;
Trigger *tg_trigger;
Buffer tg_trigtuplebuf;
Buffer tg_newtuplebuf;
TupleTableSlot *tg_trigslot;
TupleTableSlot *tg_newslot;
Tuplestorestate *tg_oldtable;
Tuplestorestate *tg_newtable;
} TriggerData;
@ -714,21 +714,21 @@ typedef struct Trigger
</varlistentry>
<varlistentry>
<term><structfield>tg_trigtuplebuf</structfield></term>
<term><structfield>tg_trigslot</structfield></term>
<listitem>
<para>
The buffer containing <structfield>tg_trigtuple</structfield>, or <symbol>InvalidBuffer</symbol> if there
is no such tuple or it is not stored in a disk buffer.
The slot containing <structfield>tg_trigtuple</structfield>,
or a <symbol>NULL</symbol> pointer if there is no such tuple.
</para>
</listitem>
</varlistentry>
<varlistentry>
<term><structfield>tg_newtuplebuf</structfield></term>
<term><structfield>tg_newslot</structfield></term>
<listitem>
<para>
The buffer containing <structfield>tg_newtuple</structfield>, or <symbol>InvalidBuffer</symbol> if there
is no such tuple or it is not stored in a disk buffer.
The slot containing <structfield>tg_newtuple</structfield>,
or a <symbol>NULL</symbol> pointer if there is no such tuple.
</para>
</listitem>
</varlistentry>

View File

@ -4258,12 +4258,17 @@ AfterTriggerExecute(EState *estate,
LocTriggerData.tg_trigtuple =
ExecFetchSlotHeapTuple(trig_tuple_slot1, true, &should_free_trig);
LocTriggerData.tg_newslot = trig_tuple_slot2;
LocTriggerData.tg_newtuple =
((evtshared->ats_event & TRIGGER_EVENT_OPMASK) ==
TRIGGER_EVENT_UPDATE) ?
ExecFetchSlotHeapTuple(trig_tuple_slot2, true, &should_free_new) : NULL;
if ((evtshared->ats_event & TRIGGER_EVENT_OPMASK) ==
TRIGGER_EVENT_UPDATE)
{
LocTriggerData.tg_newslot = trig_tuple_slot2;
LocTriggerData.tg_newtuple =
ExecFetchSlotHeapTuple(trig_tuple_slot2, true, &should_free_new);
}
else
{
LocTriggerData.tg_newtuple = NULL;
}
break;
default:
@ -4358,10 +4363,14 @@ AfterTriggerExecute(EState *estate,
if (should_free_new)
heap_freetuple(LocTriggerData.tg_newtuple);
if (LocTriggerData.tg_trigslot)
ExecClearTuple(LocTriggerData.tg_trigslot);
if (LocTriggerData.tg_newslot)
ExecClearTuple(LocTriggerData.tg_newslot);
/* don't clear slots' contents if foreign table */
if (trig_tuple_slot1 == NULL)
{
if (LocTriggerData.tg_trigslot)
ExecClearTuple(LocTriggerData.tg_trigslot);
if (LocTriggerData.tg_newslot)
ExecClearTuple(LocTriggerData.tg_newslot);
}
/*
* If doing EXPLAIN ANALYZE, stop charging time to this trigger, and count
@ -4515,13 +4524,14 @@ afterTriggerInvokeEvents(AfterTriggerEventList *events,
trigdesc = rInfo->ri_TrigDesc;
finfo = rInfo->ri_TrigFunctions;
instr = rInfo->ri_TrigInstrument;
if (slot1 != NULL)
{
ExecDropSingleTupleTableSlot(slot1);
ExecDropSingleTupleTableSlot(slot2);
slot1 = slot2 = NULL;
}
if (rel->rd_rel->relkind == RELKIND_FOREIGN_TABLE)
{
if (slot1 != NULL)
{
ExecDropSingleTupleTableSlot(slot1);
ExecDropSingleTupleTableSlot(slot2);
}
slot1 = MakeSingleTupleTableSlot(rel->rd_att,
&TTSOpsMinimalTuple);
slot2 = MakeSingleTupleTableSlot(rel->rd_att,