]> granicus.if.org Git - postgresql/blobdiff - src/backend/executor/nodeFunctionscan.c
Add macros to make AllocSetContextCreate() calls simpler and safer.
[postgresql] / src / backend / executor / nodeFunctionscan.c
index 7847b24ffe20f2e316e847cf2fefe1a36c4ad6f7..5a0f324de0aaa824fc76f33fcb27dc8c2db41574 100644 (file)
@@ -3,12 +3,12 @@
  * nodeFunctionscan.c
  *       Support routines for scanning RangeFunctions (functions in rangetable).
  *
- * Portions Copyright (c) 1996-2003, PostgreSQL Global Development Group
+ * Portions Copyright (c) 1996-2016, PostgreSQL Global Development Group
  * Portions Copyright (c) 1994, Regents of the University of California
  *
  *
  * IDENTIFICATION
- *       $PostgreSQL: pgsql/src/backend/executor/nodeFunctionscan.c,v 1.24 2004/04/01 21:28:44 tgl Exp $
+ *       src/backend/executor/nodeFunctionscan.c
  *
  *-------------------------------------------------------------------------
  */
  *             ExecFunctionNext                retrieve next tuple in sequential order.
  *             ExecInitFunctionScan    creates and initializes a functionscan node.
  *             ExecEndFunctionScan             releases any storage allocated.
- *             ExecFunctionReScan              rescans the function
+ *             ExecReScanFunctionScan  rescans the function
  */
 #include "postgres.h"
 
-#include "access/heapam.h"
 #include "catalog/pg_type.h"
-#include "executor/execdebug.h"
-#include "executor/execdefs.h"
-#include "executor/execdesc.h"
 #include "executor/nodeFunctionscan.h"
-#include "parser/parsetree.h"
-#include "parser/parse_expr.h"
-#include "parser/parse_type.h"
-#include "utils/lsyscache.h"
-#include "utils/typcache.h"
+#include "funcapi.h"
+#include "nodes/nodeFuncs.h"
+#include "utils/builtins.h"
+#include "utils/memutils.h"
 
 
+/*
+ * Runtime data for each function being scanned.
+ */
+typedef struct FunctionScanPerFuncState
+{
+       ExprState  *funcexpr;           /* state of the expression being evaluated */
+       TupleDesc       tupdesc;                /* desc of the function result type */
+       int                     colcount;               /* expected number of result columns */
+       Tuplestorestate *tstore;        /* holds the function result set */
+       int64           rowcount;               /* # of rows in result set, -1 if not known */
+       TupleTableSlot *func_slot;      /* function result slot (or NULL) */
+} FunctionScanPerFuncState;
+
 static TupleTableSlot *FunctionNext(FunctionScanState *node);
-static bool tupledesc_match(TupleDesc dst_tupdesc, TupleDesc src_tupdesc);
+
 
 /* ----------------------------------------------------------------
  *                                             Scan Support
@@ -51,63 +59,198 @@ static bool tupledesc_match(TupleDesc dst_tupdesc, TupleDesc src_tupdesc);
 static TupleTableSlot *
 FunctionNext(FunctionScanState *node)
 {
-       TupleTableSlot *slot;
        EState     *estate;
        ScanDirection direction;
-       Tuplestorestate *tuplestorestate;
-       bool            should_free;
-       HeapTuple       heapTuple;
+       TupleTableSlot *scanslot;
+       bool            alldone;
+       int64           oldpos;
+       int                     funcno;
+       int                     att;
 
        /*
         * get information from the estate and scan state
         */
        estate = node->ss.ps.state;
        direction = estate->es_direction;
+       scanslot = node->ss.ss_ScanTupleSlot;
+
+       if (node->simple)
+       {
+               /*
+                * Fast path for the trivial case: the function return type and scan
+                * result type are the same, so we fetch the function result straight
+                * into the scan result slot. No need to update ordinality or
+                * rowcounts either.
+                */
+               Tuplestorestate *tstore = node->funcstates[0].tstore;
+
+               /*
+                * If first time through, read all tuples from function and put them
+                * in a tuplestore. Subsequent calls just fetch tuples from
+                * tuplestore.
+                */
+               if (tstore == NULL)
+               {
+                       node->funcstates[0].tstore = tstore =
+                               ExecMakeTableFunctionResult(node->funcstates[0].funcexpr,
+                                                                                       node->ss.ps.ps_ExprContext,
+                                                                                       node->argcontext,
+                                                                                       node->funcstates[0].tupdesc,
+                                                                                 node->eflags & EXEC_FLAG_BACKWARD);
+
+                       /*
+                        * paranoia - cope if the function, which may have constructed the
+                        * tuplestore itself, didn't leave it pointing at the start. This
+                        * call is fast, so the overhead shouldn't be an issue.
+                        */
+                       tuplestore_rescan(tstore);
+               }
+
+               /*
+                * Get the next tuple from tuplestore.
+                */
+               (void) tuplestore_gettupleslot(tstore,
+                                                                          ScanDirectionIsForward(direction),
+                                                                          false,
+                                                                          scanslot);
+               return scanslot;
+       }
 
-       tuplestorestate = node->tuplestorestate;
+       /*
+        * Increment or decrement ordinal counter before checking for end-of-data,
+        * so that we can move off either end of the result by 1 (and no more than
+        * 1) without losing correct count.  See PortalRunSelect for why we can
+        * assume that we won't be called repeatedly in the end-of-data state.
+        */
+       oldpos = node->ordinal;
+       if (ScanDirectionIsForward(direction))
+               node->ordinal++;
+       else
+               node->ordinal--;
 
        /*
-        * If first time through, read all tuples from function and put them
-        * in a tuplestore. Subsequent calls just fetch tuples from
-        * tuplestore.
+        * Main loop over functions.
+        *
+        * We fetch the function results into func_slots (which match the function
+        * return types), and then copy the values to scanslot (which matches the
+        * scan result type), setting the ordinal column (if any) as well.
         */
-       if (tuplestorestate == NULL)
+       ExecClearTuple(scanslot);
+       att = 0;
+       alldone = true;
+       for (funcno = 0; funcno < node->nfuncs; funcno++)
        {
-               ExprContext *econtext = node->ss.ps.ps_ExprContext;
-               TupleDesc       funcTupdesc;
+               FunctionScanPerFuncState *fs = &node->funcstates[funcno];
+               int                     i;
 
-               node->tuplestorestate = tuplestorestate =
-                       ExecMakeTableFunctionResult(node->funcexpr,
-                                                                               econtext,
-                                                                               node->tupdesc,
-                                                                               &funcTupdesc);
+               /*
+                * If first time through, read all tuples from function and put them
+                * in a tuplestore. Subsequent calls just fetch tuples from
+                * tuplestore.
+                */
+               if (fs->tstore == NULL)
+               {
+                       fs->tstore =
+                               ExecMakeTableFunctionResult(fs->funcexpr,
+                                                                                       node->ss.ps.ps_ExprContext,
+                                                                                       node->argcontext,
+                                                                                       fs->tupdesc,
+                                                                                 node->eflags & EXEC_FLAG_BACKWARD);
+
+                       /*
+                        * paranoia - cope if the function, which may have constructed the
+                        * tuplestore itself, didn't leave it pointing at the start. This
+                        * call is fast, so the overhead shouldn't be an issue.
+                        */
+                       tuplestore_rescan(fs->tstore);
+               }
 
                /*
-                * If function provided a tupdesc, cross-check it.      We only really
-                * need to do this for functions returning RECORD, but might as
-                * well do it always.
+                * Get the next tuple from tuplestore.
+                *
+                * If we have a rowcount for the function, and we know the previous
+                * read position was out of bounds, don't try the read. This allows
+                * backward scan to work when there are mixed row counts present.
                 */
-               if (funcTupdesc && !tupledesc_match(node->tupdesc, funcTupdesc))
-                       ereport(ERROR,
-                                       (errcode(ERRCODE_DATATYPE_MISMATCH),
-                                        errmsg("query-specified return row and actual function return row do not match")));
+               if (fs->rowcount != -1 && fs->rowcount < oldpos)
+                       ExecClearTuple(fs->func_slot);
+               else
+                       (void) tuplestore_gettupleslot(fs->tstore,
+                                                                                  ScanDirectionIsForward(direction),
+                                                                                  false,
+                                                                                  fs->func_slot);
+
+               if (TupIsNull(fs->func_slot))
+               {
+                       /*
+                        * If we ran out of data for this function in the forward
+                        * direction then we now know how many rows it returned. We need
+                        * to know this in order to handle backwards scans. The row count
+                        * we store is actually 1+ the actual number, because we have to
+                        * position the tuplestore 1 off its end sometimes.
+                        */
+                       if (ScanDirectionIsForward(direction) && fs->rowcount == -1)
+                               fs->rowcount = node->ordinal;
+
+                       /*
+                        * populate the result cols with nulls
+                        */
+                       for (i = 0; i < fs->colcount; i++)
+                       {
+                               scanslot->tts_values[att] = (Datum) 0;
+                               scanslot->tts_isnull[att] = true;
+                               att++;
+                       }
+               }
+               else
+               {
+                       /*
+                        * we have a result, so just copy it to the result cols.
+                        */
+                       slot_getallattrs(fs->func_slot);
+
+                       for (i = 0; i < fs->colcount; i++)
+                       {
+                               scanslot->tts_values[att] = fs->func_slot->tts_values[i];
+                               scanslot->tts_isnull[att] = fs->func_slot->tts_isnull[i];
+                               att++;
+                       }
+
+                       /*
+                        * We're not done until every function result is exhausted; we pad
+                        * the shorter results with nulls until then.
+                        */
+                       alldone = false;
+               }
        }
 
        /*
-        * Get the next tuple from tuplestore. Return NULL if no more tuples.
+        * ordinal col is always last, per spec.
         */
-       slot = node->ss.ss_ScanTupleSlot;
-       if (tuplestorestate)
-               heapTuple = tuplestore_getheaptuple(tuplestorestate,
-                                                                          ScanDirectionIsForward(direction),
-                                                                                       &should_free);
-       else
+       if (node->ordinality)
        {
-               heapTuple = NULL;
-               should_free = false;
+               scanslot->tts_values[att] = Int64GetDatumFast(node->ordinal);
+               scanslot->tts_isnull[att] = false;
        }
 
-       return ExecStoreTuple(heapTuple, slot, InvalidBuffer, should_free);
+       /*
+        * If alldone, we just return the previously-cleared scanslot.  Otherwise,
+        * finish creating the virtual tuple.
+        */
+       if (!alldone)
+               ExecStoreVirtualTuple(scanslot);
+
+       return scanslot;
+}
+
+/*
+ * FunctionRecheck -- access method routine to recheck a tuple in EvalPlanQual
+ */
+static bool
+FunctionRecheck(FunctionScanState *node, TupleTableSlot *slot)
+{
+       /* nothing to check */
+       return true;
 }
 
 /* ----------------------------------------------------------------
@@ -115,18 +258,16 @@ FunctionNext(FunctionScanState *node)
  *
  *             Scans the function sequentially and returns the next qualifying
  *             tuple.
- *             It calls the ExecScan() routine and passes it the access method
- *             which retrieves tuples sequentially.
- *
+ *             We call the ExecScan() routine and pass it the appropriate
+ *             access method functions.
+ * ----------------------------------------------------------------
  */
-
 TupleTableSlot *
 ExecFunctionScan(FunctionScanState *node)
 {
-       /*
-        * use FunctionNext as access method
-        */
-       return ExecScan(&node->ss, (ExecScanAccessMtd) FunctionNext);
+       return ExecScan(&node->ss,
+                                       (ExecScanAccessMtd) FunctionNext,
+                                       (ExecScanRecheckMtd) FunctionRecheck);
 }
 
 /* ----------------------------------------------------------------
@@ -134,13 +275,17 @@ ExecFunctionScan(FunctionScanState *node)
  * ----------------------------------------------------------------
  */
 FunctionScanState *
-ExecInitFunctionScan(FunctionScan *node, EState *estate)
+ExecInitFunctionScan(FunctionScan *node, EState *estate, int eflags)
 {
        FunctionScanState *scanstate;
-       RangeTblEntry *rte;
-       Oid                     funcrettype;
-       char            functyptype;
-       TupleDesc       tupdesc = NULL;
+       int                     nfuncs = list_length(node->functions);
+       TupleDesc       scan_tupdesc;
+       int                     i,
+                               natts;
+       ListCell   *lc;
+
+       /* check for unsupported flags */
+       Assert(!(eflags & EXEC_FLAG_MARK));
 
        /*
         * FunctionScan should not have any children.
@@ -154,6 +299,30 @@ ExecInitFunctionScan(FunctionScan *node, EState *estate)
        scanstate = makeNode(FunctionScanState);
        scanstate->ss.ps.plan = (Plan *) node;
        scanstate->ss.ps.state = estate;
+       scanstate->eflags = eflags;
+
+       /*
+        * are we adding an ordinality column?
+        */
+       scanstate->ordinality = node->funcordinality;
+
+       scanstate->nfuncs = nfuncs;
+       if (nfuncs == 1 && !node->funcordinality)
+               scanstate->simple = true;
+       else
+               scanstate->simple = false;
+
+       /*
+        * Ordinal 0 represents the "before the first row" position.
+        *
+        * We need to track ordinal position even when not adding an ordinality
+        * column to the result, in order to handle backwards scanning properly
+        * with multiple functions with different result sizes. (We can't position
+        * any individual function's tuplestore any more than 1 place beyond its
+        * end, so when scanning backwards, we need to know when to start
+        * including the function in the scan again.)
+        */
+       scanstate->ordinal = 0;
 
        /*
         * Miscellaneous initialization
@@ -162,7 +331,7 @@ ExecInitFunctionScan(FunctionScan *node, EState *estate)
         */
        ExecAssignExprContext(estate, &scanstate->ss.ps);
 
-#define FUNCTIONSCAN_NSLOTS 2
+       scanstate->ss.ps.ps_TupFromTlist = false;
 
        /*
         * tuple table initialization
@@ -180,86 +349,170 @@ ExecInitFunctionScan(FunctionScan *node, EState *estate)
                ExecInitExpr((Expr *) node->scan.plan.qual,
                                         (PlanState *) scanstate);
 
-       /*
-        * get info about function
-        */
-       rte = rt_fetch(node->scan.scanrelid, estate->es_range_table);
-       Assert(rte->rtekind == RTE_FUNCTION);
-       funcrettype = exprType(rte->funcexpr);
-
-       /*
-        * Now determine if the function returns a simple or composite type,
-        * and build an appropriate tupdesc.
-        */
-       functyptype = get_typtype(funcrettype);
+       scanstate->funcstates = palloc(nfuncs * sizeof(FunctionScanPerFuncState));
 
-       if (functyptype == 'c')
+       natts = 0;
+       i = 0;
+       foreach(lc, node->functions)
        {
-               /* Composite data type, e.g. a table's row type */
-               tupdesc = CreateTupleDescCopy(lookup_rowtype_tupdesc(funcrettype, -1));
-       }
-       else if (functyptype == 'b' || functyptype == 'd')
-       {
-               /* Must be a base data type, i.e. scalar */
-               char       *attname = strVal(lfirst(rte->eref->colnames));
-
-               tupdesc = CreateTemplateTupleDesc(1, false);
-               TupleDescInitEntry(tupdesc,
-                                                  (AttrNumber) 1,
-                                                  attname,
-                                                  funcrettype,
-                                                  -1,
-                                                  0);
+               RangeTblFunction *rtfunc = (RangeTblFunction *) lfirst(lc);
+               Node       *funcexpr = rtfunc->funcexpr;
+               int                     colcount = rtfunc->funccolcount;
+               FunctionScanPerFuncState *fs = &scanstate->funcstates[i];
+               TypeFuncClass functypclass;
+               Oid                     funcrettype;
+               TupleDesc       tupdesc;
+
+               fs->funcexpr = ExecInitExpr((Expr *) funcexpr, (PlanState *) scanstate);
+
+               /*
+                * Don't allocate the tuplestores; the actual calls to the functions
+                * do that.  NULL means that we have not called the function yet (or
+                * need to call it again after a rescan).
+                */
+               fs->tstore = NULL;
+               fs->rowcount = -1;
+
+               /*
+                * Now determine if the function returns a simple or composite type,
+                * and build an appropriate tupdesc.  Note that in the composite case,
+                * the function may now return more columns than it did when the plan
+                * was made; we have to ignore any columns beyond "colcount".
+                */
+               functypclass = get_expr_result_type(funcexpr,
+                                                                                       &funcrettype,
+                                                                                       &tupdesc);
+
+               if (functypclass == TYPEFUNC_COMPOSITE)
+               {
+                       /* Composite data type, e.g. a table's row type */
+                       Assert(tupdesc);
+                       Assert(tupdesc->natts >= colcount);
+                       /* Must copy it out of typcache for safety */
+                       tupdesc = CreateTupleDescCopy(tupdesc);
+               }
+               else if (functypclass == TYPEFUNC_SCALAR)
+               {
+                       /* Base data type, i.e. scalar */
+                       tupdesc = CreateTemplateTupleDesc(1, false);
+                       TupleDescInitEntry(tupdesc,
+                                                          (AttrNumber) 1,
+                                                          NULL,        /* don't care about the name here */
+                                                          funcrettype,
+                                                          -1,
+                                                          0);
+                       TupleDescInitEntryCollation(tupdesc,
+                                                                               (AttrNumber) 1,
+                                                                               exprCollation(funcexpr));
+               }
+               else if (functypclass == TYPEFUNC_RECORD)
+               {
+                       tupdesc = BuildDescFromLists(rtfunc->funccolnames,
+                                                                                rtfunc->funccoltypes,
+                                                                                rtfunc->funccoltypmods,
+                                                                                rtfunc->funccolcollations);
+
+                       /*
+                        * For RECORD results, make sure a typmod has been assigned.  (The
+                        * function should do this for itself, but let's cover things in
+                        * case it doesn't.)
+                        */
+                       BlessTupleDesc(tupdesc);
+               }
+               else
+               {
+                       /* crummy error message, but parser should have caught this */
+                       elog(ERROR, "function in FROM has unsupported return type");
+               }
+
+               fs->tupdesc = tupdesc;
+               fs->colcount = colcount;
+
+               /*
+                * We only need separate slots for the function results if we are
+                * doing ordinality or multiple functions; otherwise, we'll fetch
+                * function results directly into the scan slot.
+                */
+               if (!scanstate->simple)
+               {
+                       fs->func_slot = ExecInitExtraTupleSlot(estate);
+                       ExecSetSlotDescriptor(fs->func_slot, fs->tupdesc);
+               }
+               else
+                       fs->func_slot = NULL;
+
+               natts += colcount;
+               i++;
        }
-       else if (funcrettype == RECORDOID)
+
+       /*
+        * Create the combined TupleDesc
+        *
+        * If there is just one function without ordinality, the scan result
+        * tupdesc is the same as the function result tupdesc --- except that we
+        * may stuff new names into it below, so drop any rowtype label.
+        */
+       if (scanstate->simple)
        {
-               /* Must be a pseudo type, i.e. record */
-               tupdesc = BuildDescForRelation(rte->coldeflist);
+               scan_tupdesc = CreateTupleDescCopy(scanstate->funcstates[0].tupdesc);
+               scan_tupdesc->tdtypeid = RECORDOID;
+               scan_tupdesc->tdtypmod = -1;
        }
        else
        {
-               /* crummy error message, but parser should have caught this */
-               elog(ERROR, "function in FROM has unsupported return type");
+               AttrNumber      attno = 0;
+
+               if (node->funcordinality)
+                       natts++;
+
+               scan_tupdesc = CreateTemplateTupleDesc(natts, false);
+
+               for (i = 0; i < nfuncs; i++)
+               {
+                       TupleDesc       tupdesc = scanstate->funcstates[i].tupdesc;
+                       int                     colcount = scanstate->funcstates[i].colcount;
+                       int                     j;
+
+                       for (j = 1; j <= colcount; j++)
+                               TupleDescCopyEntry(scan_tupdesc, ++attno, tupdesc, j);
+               }
+
+               /* If doing ordinality, add a column of type "bigint" at the end */
+               if (node->funcordinality)
+               {
+                       TupleDescInitEntry(scan_tupdesc,
+                                                          ++attno,
+                                                          NULL,        /* don't care about the name here */
+                                                          INT8OID,
+                                                          -1,
+                                                          0);
+               }
+
+               Assert(attno == natts);
        }
 
-       /*
-        * For RECORD results, make sure a typmod has been assigned.  (The
-        * function should do this for itself, but let's cover things in case
-        * it doesn't.)
-        */
-       if (tupdesc->tdtypeid == RECORDOID && tupdesc->tdtypmod < 0)
-               assign_record_type_typmod(tupdesc);
-
-       scanstate->tupdesc = tupdesc;
-       ExecSetSlotDescriptor(scanstate->ss.ss_ScanTupleSlot,
-                                                 tupdesc, false);
+       ExecAssignScanType(&scanstate->ss, scan_tupdesc);
 
        /*
-        * Other node-specific setup
+        * Initialize result tuple type and projection info.
         */
-       scanstate->tuplestorestate = NULL;
-       scanstate->funcexpr = ExecInitExpr((Expr *) rte->funcexpr,
-                                                                          (PlanState *) scanstate);
-
-       scanstate->ss.ps.ps_TupFromTlist = false;
+       ExecAssignResultTypeFromTL(&scanstate->ss.ps);
+       ExecAssignScanProjectionInfo(&scanstate->ss);
 
        /*
-        * Initialize result tuple type and projection info.
+        * Create a memory context that ExecMakeTableFunctionResult 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 just
+        * need one context, because we evaluate each function separately.
         */
-       ExecAssignResultTypeFromTL(&scanstate->ss.ps);
-       ExecAssignProjectionInfo(&scanstate->ss.ps);
+       scanstate->argcontext = AllocSetContextCreate(CurrentMemoryContext,
+                                                                                                 "Table function arguments",
+                                                                                                 ALLOCSET_DEFAULT_SIZES);
 
        return scanstate;
 }
 
-int
-ExecCountSlotsFunctionScan(FunctionScan *node)
-{
-       return ExecCountSlotsNode(outerPlan(node)) +
-               ExecCountSlotsNode(innerPlan(node)) +
-               FUNCTIONSCAN_NSLOTS;
-}
-
 /* ----------------------------------------------------------------
  *             ExecEndFunctionScan
  *
@@ -269,6 +522,8 @@ ExecCountSlotsFunctionScan(FunctionScan *node)
 void
 ExecEndFunctionScan(FunctionScanState *node)
 {
+       int                     i;
+
        /*
         * Free the exprcontext
         */
@@ -281,111 +536,84 @@ ExecEndFunctionScan(FunctionScanState *node)
        ExecClearTuple(node->ss.ss_ScanTupleSlot);
 
        /*
-        * Release tuplestore resources
-        */
-       if (node->tuplestorestate != NULL)
-               tuplestore_end(node->tuplestorestate);
-       node->tuplestorestate = NULL;
-}
-
-/* ----------------------------------------------------------------
- *             ExecFunctionMarkPos
- *
- *             Calls tuplestore to save the current position in the stored file.
- * ----------------------------------------------------------------
- */
-void
-ExecFunctionMarkPos(FunctionScanState *node)
-{
-       /*
-        * if we haven't materialized yet, just return.
+        * Release slots and tuplestore resources
         */
-       if (!node->tuplestorestate)
-               return;
-
-       tuplestore_markpos(node->tuplestorestate);
-}
+       for (i = 0; i < node->nfuncs; i++)
+       {
+               FunctionScanPerFuncState *fs = &node->funcstates[i];
 
-/* ----------------------------------------------------------------
- *             ExecFunctionRestrPos
- *
- *             Calls tuplestore to restore the last saved file position.
- * ----------------------------------------------------------------
- */
-void
-ExecFunctionRestrPos(FunctionScanState *node)
-{
-       /*
-        * if we haven't materialized yet, just return.
-        */
-       if (!node->tuplestorestate)
-               return;
+               if (fs->func_slot)
+                       ExecClearTuple(fs->func_slot);
 
-       tuplestore_restorepos(node->tuplestorestate);
+               if (fs->tstore != NULL)
+               {
+                       tuplestore_end(node->funcstates[i].tstore);
+                       fs->tstore = NULL;
+               }
+       }
 }
 
 /* ----------------------------------------------------------------
- *             ExecFunctionReScan
+ *             ExecReScanFunctionScan
  *
  *             Rescans the relation.
  * ----------------------------------------------------------------
  */
 void
-ExecFunctionReScan(FunctionScanState *node, ExprContext *exprCtxt)
+ExecReScanFunctionScan(FunctionScanState *node)
 {
+       FunctionScan *scan = (FunctionScan *) node->ss.ps.plan;
+       int                     i;
+       Bitmapset  *chgparam = node->ss.ps.chgParam;
+
        ExecClearTuple(node->ss.ps.ps_ResultTupleSlot);
+       for (i = 0; i < node->nfuncs; i++)
+       {
+               FunctionScanPerFuncState *fs = &node->funcstates[i];
 
-       /*
-        * If we haven't materialized yet, just return.
-        */
-       if (!node->tuplestorestate)
-               return;
+               if (fs->func_slot)
+                       ExecClearTuple(fs->func_slot);
+       }
+
+       ExecScanReScan(&node->ss);
 
        /*
-        * Here we have a choice whether to drop the tuplestore (and recompute
-        * the function outputs) or just rescan it.  This should depend on
-        * whether the function expression contains parameters and/or is
-        * marked volatile.  FIXME soon.
+        * Here we have a choice whether to drop the tuplestores (and recompute
+        * the function outputs) or just rescan them.  We must recompute if an
+        * expression contains changed parameters, else we rescan.
+        *
+        * XXX maybe we should recompute if the function is volatile?  But in
+        * general the executor doesn't conditionalize its actions on that.
         */
-       if (node->ss.ps.chgParam != NULL)
+       if (chgparam)
        {
-               tuplestore_end(node->tuplestorestate);
-               node->tuplestorestate = NULL;
+               ListCell   *lc;
+
+               i = 0;
+               foreach(lc, scan->functions)
+               {
+                       RangeTblFunction *rtfunc = (RangeTblFunction *) lfirst(lc);
+
+                       if (bms_overlap(chgparam, rtfunc->funcparams))
+                       {
+                               if (node->funcstates[i].tstore != NULL)
+                               {
+                                       tuplestore_end(node->funcstates[i].tstore);
+                                       node->funcstates[i].tstore = NULL;
+                               }
+                               node->funcstates[i].rowcount = -1;
+                       }
+                       i++;
+               }
        }
-       else
-               tuplestore_rescan(node->tuplestorestate);
-}
 
-/*
- * Check that function result tuple type (src_tupdesc) matches or can be
- * considered to match what the query expects (dst_tupdesc).
- *
- * We really only care about number of attributes and data type.
- * Also, we can ignore type mismatch on columns that are dropped in the
- * destination type, so long as the physical storage matches.  This is
- * helpful in some cases involving out-of-date cached plans.
- */
-static bool
-tupledesc_match(TupleDesc dst_tupdesc, TupleDesc src_tupdesc)
-{
-       int                     i;
+       /* Reset ordinality counter */
+       node->ordinal = 0;
 
-       if (dst_tupdesc->natts != src_tupdesc->natts)
-               return false;
-
-       for (i = 0; i < dst_tupdesc->natts; i++)
+       /* Make sure we rewind any remaining tuplestores */
+       for (i = 0; i < node->nfuncs; i++)
        {
-               Form_pg_attribute dattr = dst_tupdesc->attrs[i];
-               Form_pg_attribute sattr = src_tupdesc->attrs[i];
-
-               if (dattr->atttypid == sattr->atttypid)
-                       continue;                       /* no worries */
-               if (!dattr->attisdropped)
-                       return false;
-               if (dattr->attlen != sattr->attlen ||
-                       dattr->attalign != sattr->attalign)
-                       return false;
+               if (node->funcstates[i].tstore != NULL)
+                       tuplestore_rescan(node->funcstates[i].tstore);
        }
-
-       return true;
 }