fix memory usage in SRF

src/gausskernel/runtime/executor/execSRF.cpp

@@ -185,9 +185,14 @@ FuncExprState *ExecInitFunctionResultSet(Expr *expr, ExprContext *econtext, Plan
  * 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, argContext
+ * needs to live until all rows have been returned (i.e. *isDone set to
+ * ExprEndResult or ExprSingleResult).
+ *
  * This is used by nodeProjectSet.c.
  */
-Datum ExecMakeFunctionResultSet(FuncExprState *fcache, ExprContext *econtext, bool *isNull, ExprDoneCond *isDone)
+Datum ExecMakeFunctionResultSet(FuncExprState *fcache, ExprContext *econtext, MemoryContext argContext,
+                                bool *isNull, ExprDoneCond *isDone)
 {
     List	   *arguments;
     Datum		result;
@@ -215,8 +220,19 @@ restart:
      */
     if (fcache->funcResultStore)
     {
+        TupleTableSlot *slot = fcache->funcResultSlot;
+        MemoryContext oldContext;
+        bool foundTup;
         econtext->hasSetResultStore = true;
-        if (tuplestore_gettupleslot(fcache->funcResultStore, true, false, fcache->funcResultSlot)) {
+        /*
+         * Have to make sure tuple in slot lives long enough, otherwise
+         * clearing the slot could end up trying to free something already
+         * freed.
+         */
+        oldContext = MemoryContextSwitchTo(slot->tts_mcxt);
+        foundTup = tuplestore_gettupleslot(fcache->funcResultStore, true, false, fcache->funcResultSlot);
+        MemoryContextSwitchTo(oldContext);
+        if (foundTup) {
             *isDone = ExprMultipleResult;
             if (fcache->funcReturnsTuple) {
                 /* We must return the whole tuple as a Datum. */
@@ -265,10 +281,12 @@ restart:
 
     arguments = fcache->args;
     if (!fcache->setArgsValid) {
+        MemoryContext oldContext = MemoryContextSwitchTo(argContext);
         if (has_refcursor)
             ExecEvalFuncArgs<true>(fcinfo, arguments, econtext, var_dno);
         else
             ExecEvalFuncArgs<false>(fcinfo, arguments, econtext);
+        MemoryContextSwitchTo(oldContext);
     } else {
         /* Reset flag (we may set it again below) */
         fcache->setArgsValid = false;

src/gausskernel/runtime/executor/nodeProjectSet.cpp

@@ -99,6 +99,16 @@ ExecInitProjectSet(ProjectSet *node, EState *estate, int eflags)
         off++;
     }
 
+    /*
+     * Create a memory context that ExecMakeFunctionResult can use to evaluate
+     * function arguments in.  We can't use the per-tuple context for this
+     * because it gets reset too often; but we don't want to leak evaluation
+     * results into the query-lifespan context either.  We use one context for
+     * the arguments of all tSRFs, as they have roughly equivalent lifetimes.
+     */
+    state->argcontext = AllocSetContextCreate(CurrentMemoryContext,
+                                        "tSRF function arguments", ALLOCSET_DEFAULT_SIZES);
+
     return state;
 }
 
@@ -110,6 +120,13 @@ static TupleTableSlot *ExecProjectSet(PlanState *state)
     PlanState *outerPlan;
     ExprContext *econtext = node->ps.ps_ExprContext;
 
+    /*
+     * Reset per-tuple context to free expression-evaluation storage allocated
+     * for a potentially previously returned tuple. Note that the SRF argument
+     * context has a different lifetime and is reset below.
+     */
+    ResetExprContext(econtext);
+
     CHECK_FOR_INTERRUPTS();
 
     /*
@@ -125,11 +142,13 @@ static TupleTableSlot *ExecProjectSet(PlanState *state)
     }
 
     /*
-     * Reset per-tuple memory context to free any expression evaluation
-     * storage allocated in the previous tuple cycle.  Note this can't happen
-     * until we're done projecting out tuples from a scan tuple.
+     * Reset argument context to free any expression evaluation storage
+     * allocated in the previous tuple cycle.  Note this can't happen until
+     * we're done projecting out tuples from a scan tuple, as ValuePerCall
+     * functions are allowed to reference the arguments for each returned
+     * tuple.
      */
-    ResetExprContext(econtext);
+    MemoryContextReset(node->argcontext);
 
     /*
      * Get another input tuple and project SRFs from it.
@@ -166,15 +185,15 @@ static TupleTableSlot *ExecProjectSet(PlanState *state)
 }
 
 static inline Datum 
-execMakeExprResult(Node *arg, ExprContext *econtext, bool *isnull,
-                    ExprDoneCond *isdone, bool *hassrf)
+execMakeExprResult(Node *arg, ExprContext *econtext, MemoryContext argContext,
+                   bool *isnull, ExprDoneCond *isdone, bool *hassrf)
 {
     Datum result;
     if (IsA(arg, FuncExprState)) {
         /*
          * Evaluate SRF - possibly continuing previously started output.
          */
-        result = ExecMakeFunctionResultSet((FuncExprState*)arg, econtext, isnull, isdone);
+        result = ExecMakeFunctionResultSet((FuncExprState*)arg, econtext, argContext, isnull, isdone);
         *hassrf = true;
     } else {
         /* Non-SRF tlist expression, just evaluate normally. */
@@ -233,7 +252,8 @@ static TupleTableSlot *ExecProjectSRF(ProjectSetState *node)
 
         ELOG_FIELD_NAME_START(resname);
 
-        *result = execMakeExprResult(elem, econtext, isnull, itemIsDone, &hassrf);
+        *result = execMakeExprResult(elem, econtext, node->argcontext,
+                                     isnull, itemIsDone, &hassrf);
 
         ELOG_FIELD_NAME_END;
 
@@ -299,7 +319,8 @@ static TupleTableSlot *ExecProjectSRF(ProjectSetState *node)
             ELOG_FIELD_NAME_START(resname);
 
             /*restart the done ones*/
-            *result = ExecMakeFunctionResultSet((FuncExprState*)elem, econtext, isnull, itemIsDone);
+            *result = ExecMakeFunctionResultSet((FuncExprState*)elem, econtext,
+                                                node->argcontext, isnull, itemIsDone);
 
             ELOG_FIELD_NAME_END;
 
@@ -354,7 +375,8 @@ static TupleTableSlot *ExecProjectSRF(ProjectSetState *node)
                 ELOG_FIELD_NAME_START(resname);
 
                 while (*itemIsDone == ExprMultipleResult) {
-                    *result = ExecMakeFunctionResultSet((FuncExprState*)elem, econtext, isnull, itemIsDone);
+                    *result = ExecMakeFunctionResultSet((FuncExprState*)elem, econtext,
+                                                        node->argcontext, isnull, itemIsDone);
                     /* no need for MakeExpandedObjectReadOnly */
                 }
                 

src/include/executor/executor.h

@@ -342,6 +342,7 @@ extern FuncExprState *ExecInitTableFunctionResult(Expr *expr, ExprContext *econt
 extern FuncExprState *ExecInitFunctionResultSet(Expr *expr, ExprContext *econtext, PlanState *parent);
 extern Datum ExecMakeFunctionResultSet(FuncExprState *fcache,
                                        ExprContext *econtext,
+                                       MemoryContext argContext,
                                        bool *isNull,
                                        ExprDoneCond *isDone);
 

src/include/nodes/execnodes.h

@@ -1475,6 +1475,7 @@ typedef struct ProjectSetState {
     ExprDoneCond *elemdone;  /* array of per-SRF is-done states */
     int nelems;              /* length of elemdone[] array */
     bool pending_srf_tuples; /* still evaluating srfs in tlist? */
+    MemoryContext argcontext; /* context for SRF arguments */
 } ProjectSetState;
 
 /* ----------------