Movatterモバイル変換

[0]ホーム
URL:

Skip to content

Navigation Menu

Sign in
Appearance settings

Search code, repositories, users, issues, pull requests...

Provide feedback

We read every piece of feedback, and take your input very seriously.

Saved searches

Use saved searches to filter your results more quickly

 Sign up
Appearance settings

Commit4488142

Browse files
committed
Don't corrupt plpython's "TD" dictionary in a recursive trigger call.
If a plpython-language trigger caused another one to be invoked,the "TD" dictionary created for the inner one would overwrite theouter one's "TD" dictionary. This is more or less the same problemthat1d2fe56 fixed for ordinary functions in plpython, so fix itthe same way, by saving and restoring "TD" during a recursiveinvocation.This fix makes an ABI-incompatible change in struct PLySavedArgs.I'm not too worried about that because it seems highly unlikely thatany extension is messing with those structs. We could imagine doingsomething weird to preserve nominal ABI compatibility in the backbranches, like keeping the saved TD object in an extra element ofnamedargs[]. However, that would only be very nominal compatibility:if anything *is* touching PLySavedArgs, it would likely do the wrongthing due to not knowing about the additional value. So I judge itnot worth the ugliness to do something different there.(I also changed struct PLyProcedure, but its added field fitsinto formerly-padding space, so that should be safe.)Per bug #18456 from Jacques Combrink. This bug is very ancient,so back-patch to all supported branches.Discussion:https://postgr.es/m/3008982.1714853799@sss.pgh.pa.us
1 parent01aeb43 commit4488142

File tree

5 files changed

+81
-3
lines changed

5 files changed

+81
-3
lines changed

‎src/pl/plpython/expected/plpython_trigger.out

Lines changed: 27 additions & 0 deletions
Original file line numberDiff line numberDiff line change
@@ -618,3 +618,30 @@ SELECT * FROM trigger_test_generated;
618618
---+---
619619
(0 rows)
620620

621+
-- recursive call of a trigger mustn't corrupt TD (bug #18456)
622+
CREATE TABLE recursive_trigger_test (a int, b int);
623+
CREATE FUNCTION recursive_trigger_func() RETURNS trigger
624+
LANGUAGE plpythonu
625+
AS $$
626+
if TD["event"] == "UPDATE":
627+
plpy.execute("INSERT INTO recursive_trigger_test VALUES (1, 2)")
628+
plpy.notice("TD[event] => " + str(TD["event"]) + ", expecting UPDATE");
629+
else:
630+
plpy.notice("TD[event] => " + str(TD["event"]) + ", expecting INSERT");
631+
return None
632+
$$;
633+
CREATE TRIGGER recursive_trigger_trig
634+
AFTER INSERT OR UPDATE ON recursive_trigger_test
635+
FOR EACH ROW EXECUTE PROCEDURE recursive_trigger_func();
636+
INSERT INTO recursive_trigger_test VALUES (0, 0);
637+
NOTICE: TD[event] => INSERT, expecting INSERT
638+
UPDATE recursive_trigger_test SET a = 11 WHERE b = 0;
639+
NOTICE: TD[event] => INSERT, expecting INSERT
640+
NOTICE: TD[event] => UPDATE, expecting UPDATE
641+
SELECT * FROM recursive_trigger_test;
642+
a | b
643+
----+---
644+
11 | 0
645+
1 | 2
646+
(2 rows)
647+

‎src/pl/plpython/plpy_exec.c

Lines changed: 27 additions & 3 deletions
Original file line numberDiff line numberDiff line change
@@ -339,6 +339,13 @@ PLy_exec_trigger(FunctionCallInfo fcinfo, PLyProcedure *proc)
339339
PLy_output_setup_tuple(&proc->result,rel_descr,proc);
340340
PLy_input_setup_tuple(&proc->result_in,rel_descr,proc);
341341

342+
/*
343+
* If the trigger is called recursively, we must push outer-level
344+
* arguments into the stack. This must be immediately before the PG_TRY
345+
* to ensure that the corresponding pop happens.
346+
*/
347+
PLy_global_args_push(proc);
348+
342349
PG_TRY();
343350
{
344351
intrcPG_USED_FOR_ASSERTS_ONLY;
@@ -405,13 +412,15 @@ PLy_exec_trigger(FunctionCallInfo fcinfo, PLyProcedure *proc)
405412
}
406413
PG_CATCH();
407414
{
415+
PLy_global_args_pop(proc);
408416
Py_XDECREF(plargs);
409417
Py_XDECREF(plrv);
410418

411419
PG_RE_THROW();
412420
}
413421
PG_END_TRY();
414422

423+
PLy_global_args_pop(proc);
415424
Py_DECREF(plargs);
416425
Py_DECREF(plrv);
417426

@@ -514,6 +523,13 @@ PLy_function_save_args(PLyProcedure *proc)
514523
result->args=PyDict_GetItemString(proc->globals,"args");
515524
Py_XINCREF(result->args);
516525

526+
/* If it's a trigger, also save "TD" */
527+
if (proc->is_trigger)
528+
{
529+
result->td=PyDict_GetItemString(proc->globals,"TD");
530+
Py_XINCREF(result->td);
531+
}
532+
517533
/* Fetch all the named arguments */
518534
if (proc->argnames)
519535
{
@@ -563,6 +579,13 @@ PLy_function_restore_args(PLyProcedure *proc, PLySavedArgs *savedargs)
563579
Py_DECREF(savedargs->args);
564580
}
565581

582+
/* Restore the "TD" object, too */
583+
if (savedargs->td)
584+
{
585+
PyDict_SetItemString(proc->globals,"TD",savedargs->td);
586+
Py_DECREF(savedargs->td);
587+
}
588+
566589
/* And free the PLySavedArgs struct */
567590
pfree(savedargs);
568591
}
@@ -581,8 +604,9 @@ PLy_function_drop_args(PLySavedArgs *savedargs)
581604
Py_XDECREF(savedargs->namedargs[i]);
582605
}
583606

584-
/* Dropref to the "args"object, too */
607+
/* Droprefs to the "args"and "TD" objects, too */
585608
Py_XDECREF(savedargs->args);
609+
Py_XDECREF(savedargs->td);
586610

587611
/* And free the PLySavedArgs struct */
588612
pfree(savedargs);
@@ -591,9 +615,9 @@ PLy_function_drop_args(PLySavedArgs *savedargs)
591615
/*
592616
* Save away any existing arguments for the given procedure, so that we can
593617
* install new values for a recursive call. This should be invoked before
594-
* doing PLy_function_build_args().
618+
* doing PLy_function_build_args() or PLy_trigger_build_args().
595619
*
596-
* NB:caller must ensure that PLy_global_args_pop gets invoked once, and
620+
* NB:callers must ensure that PLy_global_args_pop gets invoked once, and
597621
* only once, per successful completion of PLy_global_args_push. Otherwise
598622
* we'll end up out-of-sync between the actual call stack and the contents
599623
* of proc->argstack.

‎src/pl/plpython/plpy_procedure.c

Lines changed: 1 addition & 0 deletions
Original file line numberDiff line numberDiff line change
@@ -188,6 +188,7 @@ PLy_procedure_create(HeapTuple procTup, Oid fn_oid, bool is_trigger)
188188
proc->fn_readonly= (procStruct->provolatile!=PROVOLATILE_VOLATILE);
189189
proc->is_setof=procStruct->proretset;
190190
proc->is_procedure= (procStruct->prokind==PROKIND_PROCEDURE);
191+
proc->is_trigger=is_trigger;
191192
proc->src=NULL;
192193
proc->argnames=NULL;
193194
proc->args=NULL;

‎src/pl/plpython/plpy_procedure.h

Lines changed: 2 additions & 0 deletions
Original file line numberDiff line numberDiff line change
@@ -16,6 +16,7 @@ typedef struct PLySavedArgs
1616
{
1717
structPLySavedArgs*next;/* linked-list pointer */
1818
PyObject*args;/* "args" element of globals dict */
19+
PyObject*td;/* "TD" element of globals dict, if trigger */
1920
intnargs;/* length of namedargs array */
2021
PyObject*namedargs[FLEXIBLE_ARRAY_MEMBER];/* named args */
2122
}PLySavedArgs;
@@ -32,6 +33,7 @@ typedef struct PLyProcedure
3233
boolfn_readonly;
3334
boolis_setof;/* true, if function returns result set */
3435
boolis_procedure;
36+
boolis_trigger;/* called as trigger? */
3537
PLyObToDatumresult;/* Function result output conversion info */
3638
PLyDatumToObresult_in;/* For converting input tuples in a trigger */
3739
char*src;/* textual procedure code, after mangling */

‎src/pl/plpython/sql/plpython_trigger.sql

Lines changed: 24 additions & 0 deletions
Original file line numberDiff line numberDiff line change
@@ -467,3 +467,27 @@ FOR EACH ROW EXECUTE PROCEDURE generated_test_func1();
467467
TRUNCATE trigger_test_generated;
468468
INSERT INTO trigger_test_generated (i)VALUES (1);
469469
SELECT*FROM trigger_test_generated;
470+
471+
472+
-- recursive call of a trigger mustn't corrupt TD (bug #18456)
473+
474+
CREATETABLErecursive_trigger_test (aint, bint);
475+
476+
CREATEFUNCTIONrecursive_trigger_func() RETURNS trigger
477+
LANGUAGE plpythonu
478+
AS $$
479+
if TD["event"]=="UPDATE":
480+
plpy.execute("INSERT INTO recursive_trigger_test VALUES (1, 2)")
481+
plpy.notice("TD[event] =>"+ str(TD["event"])+", expecting UPDATE");
482+
else:
483+
plpy.notice("TD[event] =>"+ str(TD["event"])+", expecting INSERT");
484+
return None
485+
$$;
486+
487+
CREATETRIGGERrecursive_trigger_trig
488+
AFTER INSERTORUPDATEON recursive_trigger_test
489+
FOR EACH ROW EXECUTE PROCEDURE recursive_trigger_func();
490+
491+
INSERT INTO recursive_trigger_testVALUES (0,0);
492+
UPDATE recursive_trigger_testSET a=11WHERE b=0;
493+
SELECT*FROM recursive_trigger_test;

0 commit comments

Comments
 (0)
[8]ページ先頭
©2009-2025 Movatter.jp