nodeFunctionscan.h File Reference

#include "nodes/execnodes.h"

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Functions
FunctionScanState *	ExecInitFunctionScan (FunctionScan *node, EState *estate, int eflags)
void	ExecEndFunctionScan (FunctionScanState *node)
void	ExecReScanFunctionScan (FunctionScanState *node)

Function Documentation

ExecEndFunctionScan()

void ExecEndFunctionScan

(

FunctionScanState *

node

)

Definition at line 530 of file nodeFunctionscan.c.

{
    int         i;
 
    /*
     * Release slots and tuplestore resources
     */
    for (i = 0; i < node->nfuncs; i++)
    {
        FunctionScanPerFuncState *fs = &node->funcstates[i];
 
        if (fs->tstore != NULL)
        {
            tuplestore_end(node->funcstates[i].tstore);
            fs->tstore = NULL;
        }
    }
}

References FunctionScanState::funcstates, i, FunctionScanState::nfuncs, FunctionScanPerFuncState::tstore, and tuplestore_end().

Referenced by ExecEndNode().

ExecInitFunctionScan()

FunctionScanState * ExecInitFunctionScan	(	FunctionScan *	node,
		EState *	estate,
		int	eflags
	)

Definition at line 279 of file nodeFunctionscan.c.

{
    FunctionScanState *scanstate;
    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.
     */
    Assert(outerPlan(node) == NULL);
    Assert(innerPlan(node) == NULL);
 
    /*
     * create new ScanState for node
     */
    scanstate = makeNode(FunctionScanState);
    scanstate->ss.ps.plan = (Plan *) node;
    scanstate->ss.ps.state = estate;
    scanstate->ss.ps.ExecProcNode = ExecFunctionScan;
    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
     *
     * create expression context for node
     */
    ExecAssignExprContext(estate, &scanstate->ss.ps);
 
    scanstate->funcstates = palloc(nfuncs * sizeof(FunctionScanPerFuncState));
 
    natts = 0;
    i = 0;
    foreach(lc, node->functions)
    {
        RangeTblFunction *rtfunc = (RangeTblFunction *) lfirst(lc);
        Node       *funcexpr = rtfunc->funcexpr;
        int         colcount = rtfunc->funccolcount;
        FunctionScanPerFuncState *fs = &scanstate->funcstates[i];
        TupleDesc   tupdesc;
 
        fs->setexpr =
            ExecInitTableFunctionResult((Expr *) funcexpr,
                                        scanstate->ss.ps.ps_ExprContext,
                                        &scanstate->ss.ps);
 
        /*
         * 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 build a tupdesc showing the result type we expect from the
         * function.  If we have a coldeflist then that takes priority (note
         * the parser enforces that there is one if the function's nominal
         * output type is RECORD).  Otherwise use get_expr_result_type.
         *
         * Note that if the function returns a named composite type, that may
         * now contain more or different columns than it did when the plan was
         * made.  For both that and the RECORD case, we need to check tuple
         * compatibility.  ExecMakeTableFunctionResult handles some of this,
         * and CheckVarSlotCompatibility provides a backstop.
         */
        if (rtfunc->funccolnames != NIL)
        {
            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
        {
            TypeFuncClass functypclass;
            Oid         funcrettype;
 
            functypclass = get_expr_result_type(funcexpr,
                                                &funcrettype,
                                                &tupdesc);
 
            if (functypclass == TYPEFUNC_COMPOSITE ||
                functypclass == TYPEFUNC_COMPOSITE_DOMAIN)
            {
                /* Composite data type, e.g. a table's row type */
                Assert(tupdesc);
                /* 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);
                TupleDescInitEntry(tupdesc,
                                   (AttrNumber) 1,
                                   NULL,    /* don't care about the name here */
                                   funcrettype,
                                   -1,
                                   0);
                TupleDescInitEntryCollation(tupdesc,
                                            (AttrNumber) 1,
                                            exprCollation(funcexpr));
            }
            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, fs->tupdesc,
                                                   &TTSOpsMinimalTuple);
        }
        else
            fs->func_slot = NULL;
 
        natts += colcount;
        i++;
    }
 
    /*
     * 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)
    {
        scan_tupdesc = CreateTupleDescCopy(scanstate->funcstates[0].tupdesc);
        scan_tupdesc->tdtypeid = RECORDOID;
        scan_tupdesc->tdtypmod = -1;
    }
    else
    {
        AttrNumber  attno = 0;
 
        if (node->funcordinality)
            natts++;
 
        scan_tupdesc = CreateTemplateTupleDesc(natts);
 
        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);
    }
 
    /*
     * Initialize scan slot and type.
     */
    ExecInitScanTupleSlot(estate, &scanstate->ss, scan_tupdesc,
                          &TTSOpsMinimalTuple);
 
    /*
     * Initialize result slot, type and projection.
     */
    ExecInitResultTypeTL(&scanstate->ss.ps);
    ExecAssignScanProjectionInfo(&scanstate->ss);
 
    /*
     * initialize child expressions
     */
    scanstate->ss.ps.qual =
        ExecInitQual(node->scan.plan.qual, (PlanState *) scanstate);
 
    /*
     * 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.
     */
    scanstate->argcontext = AllocSetContextCreate(CurrentMemoryContext,
                                                  "Table function arguments",
                                                  ALLOCSET_DEFAULT_SIZES);
 
    return scanstate;
}

References ALLOCSET_DEFAULT_SIZES, AllocSetContextCreate, FunctionScanState::argcontext, Assert(), BlessTupleDesc(), BuildDescFromLists(), FunctionScanPerFuncState::colcount, CreateTemplateTupleDesc(), CreateTupleDescCopy(), CurrentMemoryContext, FunctionScanState::eflags, elog, ERROR, EXEC_FLAG_MARK, ExecAssignExprContext(), ExecAssignScanProjectionInfo(), ExecFunctionScan(), ExecInitExtraTupleSlot(), ExecInitQual(), ExecInitResultTypeTL(), ExecInitScanTupleSlot(), ExecInitTableFunctionResult(), PlanState::ExecProcNode, exprCollation(), FunctionScanPerFuncState::func_slot, RangeTblFunction::funcexpr, FunctionScan::funcordinality, FunctionScanState::funcstates, FunctionScan::functions, get_expr_result_type(), i, innerPlan, j, lfirst, list_length(), makeNode, FunctionScanState::nfuncs, NIL, FunctionScanState::ordinal, FunctionScanState::ordinality, outerPlan, palloc(), PlanState::plan, ScanState::ps, PlanState::ps_ExprContext, PlanState::qual, FunctionScanPerFuncState::rowcount, FunctionScan::scan, FunctionScanPerFuncState::setexpr, FunctionScanState::simple, FunctionScanState::ss, PlanState::state, TupleDescData::tdtypeid, TupleDescData::tdtypmod, FunctionScanPerFuncState::tstore, TTSOpsMinimalTuple, FunctionScanPerFuncState::tupdesc, TupleDescCopyEntry(), TupleDescInitEntry(), TupleDescInitEntryCollation(), TYPEFUNC_COMPOSITE, TYPEFUNC_COMPOSITE_DOMAIN, and TYPEFUNC_SCALAR.

Referenced by ExecInitNode().

ExecReScanFunctionScan()

void ExecReScanFunctionScan

(

FunctionScanState *

node

)

Definition at line 556 of file nodeFunctionscan.c.

{
    FunctionScan *scan = (FunctionScan *) node->ss.ps.plan;
    int         i;
    Bitmapset  *chgparam = node->ss.ps.chgParam;
 
    if (node->ss.ps.ps_ResultTupleSlot)
        ExecClearTuple(node->ss.ps.ps_ResultTupleSlot);
    for (i = 0; i < node->nfuncs; i++)
    {
        FunctionScanPerFuncState *fs = &node->funcstates[i];
 
        if (fs->func_slot)
            ExecClearTuple(fs->func_slot);
    }
 
    ExecScanReScan(&node->ss);
 
    /*
     * 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 (chgparam)
    {
        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++;
        }
    }
 
    /* Reset ordinality counter */
    node->ordinal = 0;
 
    /* Make sure we rewind any remaining tuplestores */
    for (i = 0; i < node->nfuncs; i++)
    {
        if (node->funcstates[i].tstore != NULL)
            tuplestore_rescan(node->funcstates[i].tstore);
    }
}

References bms_overlap(), PlanState::chgParam, ExecClearTuple(), ExecScanReScan(), FunctionScanPerFuncState::func_slot, FunctionScanState::funcstates, FunctionScan::functions, i, if(), lfirst, FunctionScanState::nfuncs, FunctionScanState::ordinal, PlanState::plan, ScanState::ps, PlanState::ps_ResultTupleSlot, FunctionScanPerFuncState::rowcount, FunctionScanState::ss, FunctionScanPerFuncState::tstore, tuplestore_end(), and tuplestore_rescan().

Referenced by ExecReScan().