I've set the CF entry to "Waiting on Author" pending a new patch
that does it like that.
With contain_mutable_functions the patch becomes trivial.
--
Konstantin Knizhnik
Postgres Professional: http://www.postgrespro.com
The Russian Postgres Company
diff --git a/src/pl/plpgsql/src/pl_exec.c b/src/pl/plpgsql/src/pl_exec.c
index a4697dc..55ed878 100644
--- a/src/pl/plpgsql/src/pl_exec.c
+++ b/src/pl/plpgsql/src/pl_exec.c
@@ -30,6 +30,7 @@
#include "funcapi.h"
#include "miscadmin.h"
#include "nodes/nodeFuncs.h"
+#include "optimizer/clauses.h"
#include "optimizer/optimizer.h"
#include "parser/parse_coerce.h"
#include "parser/parse_type.h"
@@ -6157,7 +6158,7 @@ exec_eval_simple_expr(PLpgSQL_execstate *estate,
* updates made so far by our own function.
*/
oldcontext = MemoryContextSwitchTo(get_eval_mcontext(estate));
- if (!estate->readonly_func)
+ if (!estate->readonly_func && expr->expr_needs_snapshot)
{
CommandCounterIncrement();
PushActiveSnapshot(GetTransactionSnapshot());
@@ -6182,7 +6183,7 @@ exec_eval_simple_expr(PLpgSQL_execstate *estate,
estate->paramLI->parserSetupArg = save_setup_arg;
- if (!estate->readonly_func)
+ if (!estate->readonly_func && expr->expr_needs_snapshot)
PopActiveSnapshot();
MemoryContextSwitchTo(oldcontext);
@@ -8046,6 +8047,7 @@ exec_save_simple_expr(PLpgSQL_expr *expr, CachedPlan *cplan)
* current transaction".
*/
expr->expr_simple_expr = tle_expr;
+ expr->expr_needs_snapshot = contain_mutable_functions((Node*)tle_expr);
expr->expr_simple_generation = cplan->generation;
expr->expr_simple_state = NULL;
expr->expr_simple_in_use = false;
diff --git a/src/pl/plpgsql/src/plpgsql.h b/src/pl/plpgsql/src/plpgsql.h
index f66b2ba..454131f 100644
--- a/src/pl/plpgsql/src/plpgsql.h
+++ b/src/pl/plpgsql/src/plpgsql.h
@@ -243,6 +243,7 @@ typedef struct PLpgSQL_expr
*/
ExprState *expr_simple_state; /* eval tree for expr_simple_expr */
bool expr_simple_in_use; /* true if eval tree is active */
+ bool expr_needs_snapshot; /* true if simple expression calls non-immutable functions or performs subqueries */
LocalTransactionId expr_simple_lxid;
} PLpgSQL_expr;
