postgres.git / summary / log / commit / refs

commit    a1c2c430d33e0945da234b025b78bd265c8bdfb5
Author:   Tom Lane <tgl@sss.pgh.pa.us>
Date:     Fri Oct 06 18:28:42 2017 +0000

    Fix intra-query memory leakage in nodeProjectSet.c.
    
    Both ExecMakeFunctionResultSet() and evaluation of simple expressions
    need to be done in the per-tuple memory context, not per-query, else
    we leak data until end of query.  This is a consideration that was
    missed while refactoring code in the ProjectSet patch (note that in
    pre-v10, ExecMakeFunctionResult is called in the per-tuple context).
    
    Per bug #14843 from Ben M.  Diagnosed independently by Andres and myself.
    
    Discussion: https://postgr.es/m/20171005230321.28561.15927@wrigleys.postgresql.org


 src/backend/executor/execSRF.c        | 2 ++
 src/backend/executor/nodeProjectSet.c | 6 ++++++
 2 files changed, 8 insertions(+)

diff --git a/src/backend/executor/execSRF.c b/src/backend/executor/execSRF.c
index 8bc90a6c7e8..1be683db83d 100644
--- a/src/backend/executor/execSRF.c
+++ b/src/backend/executor/execSRF.c
@@ -467,6 +467,8 @@ ExecInitFunctionResultSet(Expr *expr,
  * function itself.  The argument expressions may not contain set-returning
  * functions (the planner is supposed to have separated evaluation for those).
  *
+ * This should be called in a short-lived (per-tuple) context.
+ *
  * This is used by nodeProjectSet.c.
  */
 Datum
diff --git a/src/backend/executor/nodeProjectSet.c b/src/backend/executor/nodeProjectSet.c
index d93462c5421..68981296f90 100644
--- a/src/backend/executor/nodeProjectSet.c
+++ b/src/backend/executor/nodeProjectSet.c
@@ -124,12 +124,16 @@ ExecProjectSRF(ProjectSetState *node, bool continuing)
 {
 	TupleTableSlot *resultSlot = node->ps.ps_ResultTupleSlot;
 	ExprContext *econtext = node->ps.ps_ExprContext;
+	MemoryContext oldcontext;
 	bool		hassrf PG_USED_FOR_ASSERTS_ONLY;
 	bool		hasresult;
 	int			argno;
 
 	ExecClearTuple(resultSlot);
 
+	/* Call SRFs, as well as plain expressions, in per-tuple context */
+	oldcontext = MemoryContextSwitchTo(econtext->ecxt_per_tuple_memory);
+
 	/*
 	 * Assume no further tuples are produced unless an ExprMultipleResult is
 	 * encountered from a set returning function.
@@ -176,6 +180,8 @@ ExecProjectSRF(ProjectSetState *node, bool continuing)
 		}
 	}
 
+	MemoryContextSwitchTo(oldcontext);
+
 	/* ProjectSet should not be used if there's no SRFs */
 	Assert(hassrf);
 


[parent: 6b87416c9a4d]