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-rw-r--r--src/backend/executor/nodeFunctionscan.c620
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diff --git a/src/backend/executor/nodeFunctionscan.c b/src/backend/executor/nodeFunctionscan.c
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+/*-------------------------------------------------------------------------
+ *
+ * nodeFunctionscan.c
+ * Support routines for scanning RangeFunctions (functions in rangetable).
+ *
+ * Portions Copyright (c) 1996-2022, PostgreSQL Global Development Group
+ * Portions Copyright (c) 1994, Regents of the University of California
+ *
+ *
+ * IDENTIFICATION
+ * src/backend/executor/nodeFunctionscan.c
+ *
+ *-------------------------------------------------------------------------
+ */
+/*
+ * INTERFACE ROUTINES
+ * ExecFunctionScan scans a function.
+ * ExecFunctionNext retrieve next tuple in sequential order.
+ * ExecInitFunctionScan creates and initializes a functionscan node.
+ * ExecEndFunctionScan releases any storage allocated.
+ * ExecReScanFunctionScan rescans the function
+ */
+#include "postgres.h"
+
+#include "catalog/pg_type.h"
+#include "executor/nodeFunctionscan.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
+{
+ SetExprState *setexpr; /* 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);
+
+
+/* ----------------------------------------------------------------
+ * Scan Support
+ * ----------------------------------------------------------------
+ */
+/* ----------------------------------------------------------------
+ * FunctionNext
+ *
+ * This is a workhorse for ExecFunctionScan
+ * ----------------------------------------------------------------
+ */
+static TupleTableSlot *
+FunctionNext(FunctionScanState *node)
+{
+ EState *estate;
+ ScanDirection direction;
+ 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].setexpr,
+ 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;
+ }
+
+ /*
+ * 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--;
+
+ /*
+ * 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.
+ */
+ ExecClearTuple(scanslot);
+ att = 0;
+ alldone = true;
+ for (funcno = 0; funcno < node->nfuncs; funcno++)
+ {
+ FunctionScanPerFuncState *fs = &node->funcstates[funcno];
+ int i;
+
+ /*
+ * 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->setexpr,
+ 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);
+ }
+
+ /*
+ * 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 (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;
+ }
+ }
+
+ /*
+ * ordinal col is always last, per spec.
+ */
+ if (node->ordinality)
+ {
+ scanslot->tts_values[att] = Int64GetDatumFast(node->ordinal);
+ scanslot->tts_isnull[att] = false;
+ }
+
+ /*
+ * 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;
+}
+
+/* ----------------------------------------------------------------
+ * ExecFunctionScan(node)
+ *
+ * Scans the function sequentially and returns the next qualifying
+ * tuple.
+ * We call the ExecScan() routine and pass it the appropriate
+ * access method functions.
+ * ----------------------------------------------------------------
+ */
+static TupleTableSlot *
+ExecFunctionScan(PlanState *pstate)
+{
+ FunctionScanState *node = castNode(FunctionScanState, pstate);
+
+ return ExecScan(&node->ss,
+ (ExecScanAccessMtd) FunctionNext,
+ (ExecScanRecheckMtd) FunctionRecheck);
+}
+
+/* ----------------------------------------------------------------
+ * ExecInitFunctionScan
+ * ----------------------------------------------------------------
+ */
+FunctionScanState *
+ExecInitFunctionScan(FunctionScan *node, EState *estate, int eflags)
+{
+ 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];
+ TypeFuncClass functypclass;
+ Oid funcrettype;
+ 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 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 ||
+ functypclass == TYPEFUNC_COMPOSITE_DOMAIN)
+ {
+ /* 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);
+ 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, 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;
+}
+
+/* ----------------------------------------------------------------
+ * ExecEndFunctionScan
+ *
+ * frees any storage allocated through C routines.
+ * ----------------------------------------------------------------
+ */
+void
+ExecEndFunctionScan(FunctionScanState *node)
+{
+ int i;
+
+ /*
+ * Free the exprcontext
+ */
+ ExecFreeExprContext(&node->ss.ps);
+
+ /*
+ * clean out the tuple table
+ */
+ if (node->ss.ps.ps_ResultTupleSlot)
+ ExecClearTuple(node->ss.ps.ps_ResultTupleSlot);
+ ExecClearTuple(node->ss.ss_ScanTupleSlot);
+
+ /*
+ * Release slots and tuplestore resources
+ */
+ for (i = 0; i < node->nfuncs; i++)
+ {
+ FunctionScanPerFuncState *fs = &node->funcstates[i];
+
+ if (fs->func_slot)
+ ExecClearTuple(fs->func_slot);
+
+ if (fs->tstore != NULL)
+ {
+ tuplestore_end(node->funcstates[i].tstore);
+ fs->tstore = NULL;
+ }
+ }
+}
+
+/* ----------------------------------------------------------------
+ * ExecReScanFunctionScan
+ *
+ * Rescans the relation.
+ * ----------------------------------------------------------------
+ */
+void
+ExecReScanFunctionScan(FunctionScanState *node)
+{
+ 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);
+ }
+}
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