]> granicus.if.org Git - postgresql/blobdiff - src/backend/executor/nodeSubplan.c
Make some small planner API cleanups.
[postgresql] / src / backend / executor / nodeSubplan.c
index 59aa134e78ad9e499f4e8d01ae7a4dfcb336e88d..152696035cd5307c32241c7e581a86ac19bdc178 100644 (file)
@@ -1,9 +1,17 @@
 /*-------------------------------------------------------------------------
  *
  * nodeSubplan.c
- *       routines to support subselects
+ *       routines to support sub-selects appearing in expressions
  *
- * Portions Copyright (c) 1996-2013, PostgreSQL Global Development Group
+ * This module is concerned with executing SubPlan expression nodes, which
+ * should not be confused with sub-SELECTs appearing in FROM.  SubPlans are
+ * divided into "initplans", which are those that need only one evaluation per
+ * query (among other restrictions, this requires that they don't use any
+ * direct correlation variables from the parent plan level), and "regular"
+ * subplans, which are re-evaluated every time their result is required.
+ *
+ *
+ * Portions Copyright (c) 1996-2019, PostgreSQL Global Development Group
  * Portions Copyright (c) 1994, Regents of the University of California
  *
  * IDENTIFICATION
 #include "executor/executor.h"
 #include "executor/nodeSubplan.h"
 #include "nodes/makefuncs.h"
-#include "optimizer/clauses.h"
+#include "nodes/nodeFuncs.h"
+#include "miscadmin.h"
 #include "utils/array.h"
 #include "utils/lsyscache.h"
 #include "utils/memutils.h"
 
 
-static Datum ExecSubPlan(SubPlanState *node,
-                       ExprContext *econtext,
-                       bool *isNull,
-                       ExprDoneCond *isDone);
-static Datum ExecAlternativeSubPlan(AlternativeSubPlanState *node,
-                                          ExprContext *econtext,
-                                          bool *isNull,
-                                          ExprDoneCond *isDone);
 static Datum ExecHashSubPlan(SubPlanState *node,
                                ExprContext *econtext,
                                bool *isNull);
@@ -54,32 +55,44 @@ static bool slotNoNulls(TupleTableSlot *slot);
 
 /* ----------------------------------------------------------------
  *             ExecSubPlan
+ *
+ * This is the main entry point for execution of a regular SubPlan.
  * ----------------------------------------------------------------
  */
-static Datum
+Datum
 ExecSubPlan(SubPlanState *node,
                        ExprContext *econtext,
-                       bool *isNull,
-                       ExprDoneCond *isDone)
+                       bool *isNull)
 {
-       SubPlan    *subplan = (SubPlan *) node->xprstate.expr;
+       SubPlan    *subplan = node->subplan;
+       EState     *estate = node->planstate->state;
+       ScanDirection dir = estate->es_direction;
+       Datum           retval;
+
+       CHECK_FOR_INTERRUPTS();
 
-       /* Set default values for result flags: non-null, not a set result */
+       /* Set non-null as default */
        *isNull = false;
-       if (isDone)
-               *isDone = ExprSingleResult;
 
        /* Sanity checks */
        if (subplan->subLinkType == CTE_SUBLINK)
                elog(ERROR, "CTE subplans should not be executed via ExecSubPlan");
-       if (subplan->setParam != NIL)
+       if (subplan->setParam != NIL && subplan->subLinkType != MULTIEXPR_SUBLINK)
                elog(ERROR, "cannot set parent params from subquery");
 
+       /* Force forward-scan mode for evaluation */
+       estate->es_direction = ForwardScanDirection;
+
        /* Select appropriate evaluation strategy */
        if (subplan->useHashTable)
-               return ExecHashSubPlan(node, econtext, isNull);
+               retval = ExecHashSubPlan(node, econtext, isNull);
        else
-               return ExecScanSubPlan(node, econtext, isNull);
+               retval = ExecScanSubPlan(node, econtext, isNull);
+
+       /* restore scan direction */
+       estate->es_direction = dir;
+
+       return retval;
 }
 
 /*
@@ -90,7 +103,7 @@ ExecHashSubPlan(SubPlanState *node,
                                ExprContext *econtext,
                                bool *isNull)
 {
-       SubPlan    *subplan = (SubPlan *) node->xprstate.expr;
+       SubPlan    *subplan = node->subplan;
        PlanState  *planstate = node->planstate;
        TupleTableSlot *slot;
 
@@ -118,7 +131,7 @@ ExecHashSubPlan(SubPlanState *node,
         * have to set the econtext to use (hack alert!).
         */
        node->projLeft->pi_exprContext = econtext;
-       slot = ExecProject(node->projLeft, NULL);
+       slot = ExecProject(node->projLeft);
 
        /*
         * Note: because we are typically called in a per-tuple context, we have
@@ -147,7 +160,7 @@ ExecHashSubPlan(SubPlanState *node,
                if (node->havehashrows &&
                        FindTupleHashEntry(node->hashtable,
                                                           slot,
-                                                          node->cur_eq_funcs,
+                                                          node->cur_eq_comp,
                                                           node->lhs_hash_funcs) != NULL)
                {
                        ExecClearTuple(slot);
@@ -212,16 +225,47 @@ ExecScanSubPlan(SubPlanState *node,
                                ExprContext *econtext,
                                bool *isNull)
 {
-       SubPlan    *subplan = (SubPlan *) node->xprstate.expr;
+       SubPlan    *subplan = node->subplan;
        PlanState  *planstate = node->planstate;
        SubLinkType subLinkType = subplan->subLinkType;
        MemoryContext oldcontext;
        TupleTableSlot *slot;
        Datum           result;
-       bool            found = false;  /* TRUE if got at least one subplan tuple */
+       bool            found = false;  /* true if got at least one subplan tuple */
        ListCell   *pvar;
        ListCell   *l;
-       ArrayBuildState *astate = NULL;
+       ArrayBuildStateAny *astate = NULL;
+
+       /*
+        * MULTIEXPR subplans, when "executed", just return NULL; but first we
+        * mark the subplan's output parameters as needing recalculation.  (This
+        * is a bit of a hack: it relies on the subplan appearing later in its
+        * targetlist than any of the referencing Params, so that all the Params
+        * have been evaluated before we re-mark them for the next evaluation
+        * cycle.  But in general resjunk tlist items appear after non-resjunk
+        * ones, so this should be safe.)  Unlike ExecReScanSetParamPlan, we do
+        * *not* set bits in the parent plan node's chgParam, because we don't
+        * want to cause a rescan of the parent.
+        */
+       if (subLinkType == MULTIEXPR_SUBLINK)
+       {
+               EState     *estate = node->parent->state;
+
+               foreach(l, subplan->setParam)
+               {
+                       int                     paramid = lfirst_int(l);
+                       ParamExecData *prm = &(estate->es_param_exec_vals[paramid]);
+
+                       prm->execPlan = node;
+               }
+               *isNull = true;
+               return (Datum) 0;
+       }
+
+       /* Initialize ArrayBuildStateAny in caller's context, if needed */
+       if (subLinkType == ARRAY_SUBLINK)
+               astate = initArrayResultAny(subplan->firstColType,
+                                                                       CurrentMemoryContext, true);
 
        /*
         * We are probably in a short-lived expression-evaluation context. Switch
@@ -244,8 +288,7 @@ ExecScanSubPlan(SubPlanState *node,
 
                prm->value = ExecEvalExprSwitchContext((ExprState *) lfirst(pvar),
                                                                                           econtext,
-                                                                                          &(prm->isnull),
-                                                                                          NULL);
+                                                                                          &(prm->isnull));
                planstate->chgParam = bms_add_member(planstate->chgParam, paramid);
        }
 
@@ -261,12 +304,12 @@ ExecScanSubPlan(SubPlanState *node,
         * semantics for ANY_SUBLINK or AND semantics for ALL_SUBLINK.
         * (ROWCOMPARE_SUBLINK doesn't allow multiple tuples from the subplan.)
         * NULL results from the combining operators are handled according to the
-        * usual SQL semantics for OR and AND.  The result for no input tuples is
+        * usual SQL semantics for OR and AND.  The result for no input tuples is
         * FALSE for ANY_SUBLINK, TRUE for ALL_SUBLINK, NULL for
         * ROWCOMPARE_SUBLINK.
         *
         * For EXPR_SUBLINK we require the subplan to produce no more than one
-        * tuple, else an error is raised.      If zero tuples are produced, we return
+        * tuple, else an error is raised.  If zero tuples are produced, we return
         * NULL.  Assuming we get a tuple, we just use its first column (there can
         * be only one non-junk column in this case).
         *
@@ -314,7 +357,7 @@ ExecScanSubPlan(SubPlanState *node,
                         */
                        if (node->curTuple)
                                heap_freetuple(node->curTuple);
-                       node->curTuple = ExecCopySlotTuple(slot);
+                       node->curTuple = ExecCopySlotHeapTuple(slot);
 
                        result = heap_getattr(node->curTuple, 1, tdesc, isNull);
                        /* keep scanning subplan to make sure there's only one tuple */
@@ -328,10 +371,10 @@ ExecScanSubPlan(SubPlanState *node,
 
                        found = true;
                        /* stash away current value */
-                       Assert(subplan->firstColType == tdesc->attrs[0]->atttypid);
+                       Assert(subplan->firstColType == TupleDescAttr(tdesc, 0)->atttypid);
                        dvalue = slot_getattr(slot, 1, &disnull);
-                       astate = accumArrayResult(astate, dvalue, disnull,
-                                                                         subplan->firstColType, oldcontext);
+                       astate = accumArrayResultAny(astate, dvalue, disnull,
+                                                                                subplan->firstColType, oldcontext);
                        /* keep scanning subplan to collect all values */
                        continue;
                }
@@ -362,7 +405,7 @@ ExecScanSubPlan(SubPlanState *node,
                }
 
                rowresult = ExecEvalExprSwitchContext(node->testexpr, econtext,
-                                                                                         &rownull, NULL);
+                                                                                         &rownull);
 
                if (subLinkType == ANY_SUBLINK)
                {
@@ -401,15 +444,12 @@ ExecScanSubPlan(SubPlanState *node,
        if (subLinkType == ARRAY_SUBLINK)
        {
                /* We return the result in the caller's context */
-               if (astate != NULL)
-                       result = makeArrayResult(astate, oldcontext);
-               else
-                       result = PointerGetDatum(construct_empty_array(subplan->firstColType));
+               result = makeArrayResultAny(astate, oldcontext, true);
        }
        else if (!found)
        {
                /*
-                * deal with empty subplan result.      result/isNull were previously
+                * deal with empty subplan result.  result/isNull were previously
                 * initialized correctly for all sublink types except EXPR and
                 * ROWCOMPARE; for those, return NULL.
                 */
@@ -430,7 +470,7 @@ ExecScanSubPlan(SubPlanState *node,
 static void
 buildSubPlanHash(SubPlanState *node, ExprContext *econtext)
 {
-       SubPlan    *subplan = (SubPlan *) node->xprstate.expr;
+       SubPlan    *subplan = node->subplan;
        PlanState  *planstate = node->planstate;
        int                     ncols = list_length(subplan->paramIds);
        ExprContext *innerecontext = node->innerecontext;
@@ -465,14 +505,17 @@ buildSubPlanHash(SubPlanState *node, ExprContext *econtext)
        if (nbuckets < 1)
                nbuckets = 1;
 
-       node->hashtable = BuildTupleHashTable(ncols,
+       node->hashtable = BuildTupleHashTable(node->parent,
+                                                                                 node->descRight,
+                                                                                 ncols,
                                                                                  node->keyColIdx,
-                                                                                 node->tab_eq_funcs,
+                                                                                 node->tab_eq_funcoids,
                                                                                  node->tab_hash_funcs,
                                                                                  nbuckets,
-                                                                                 sizeof(TupleHashEntryData),
+                                                                                 0,
                                                                                  node->hashtablecxt,
-                                                                                 node->hashtempcxt);
+                                                                                 node->hashtempcxt,
+                                                                                 false);
 
        if (!subplan->unknownEqFalse)
        {
@@ -484,14 +527,17 @@ buildSubPlanHash(SubPlanState *node, ExprContext *econtext)
                        if (nbuckets < 1)
                                nbuckets = 1;
                }
-               node->hashnulls = BuildTupleHashTable(ncols,
+               node->hashnulls = BuildTupleHashTable(node->parent,
+                                                                                         node->descRight,
+                                                                                         ncols,
                                                                                          node->keyColIdx,
-                                                                                         node->tab_eq_funcs,
+                                                                                         node->tab_eq_funcoids,
                                                                                          node->tab_hash_funcs,
                                                                                          nbuckets,
-                                                                                         sizeof(TupleHashEntryData),
+                                                                                         0,
                                                                                          node->hashtablecxt,
-                                                                                         node->hashtempcxt);
+                                                                                         node->hashtempcxt,
+                                                                                         false);
        }
 
        /*
@@ -532,7 +578,7 @@ buildSubPlanHash(SubPlanState *node, ExprContext *econtext)
                                                                                  &(prmdata->isnull));
                        col++;
                }
-               slot = ExecProject(node->projRight, NULL);
+               slot = ExecProject(node->projRight);
 
                /*
                 * If result contains any nulls, store separately or not at all.
@@ -562,11 +608,82 @@ buildSubPlanHash(SubPlanState *node, ExprContext *econtext)
         * potential for a double free attempt.  (XXX possibly no longer needed,
         * but can't hurt.)
         */
-       ExecClearTuple(node->projRight->pi_slot);
+       ExecClearTuple(node->projRight->pi_state.resultslot);
 
        MemoryContextSwitchTo(oldcontext);
 }
 
+/*
+ * execTuplesUnequal
+ *             Return true if two tuples are definitely unequal in the indicated
+ *             fields.
+ *
+ * Nulls are neither equal nor unequal to anything else.  A true result
+ * is obtained only if there are non-null fields that compare not-equal.
+ *
+ * slot1, slot2: the tuples to compare (must have same columns!)
+ * numCols: the number of attributes to be examined
+ * matchColIdx: array of attribute column numbers
+ * eqFunctions: array of fmgr lookup info for the equality functions to use
+ * evalContext: short-term memory context for executing the functions
+ */
+static bool
+execTuplesUnequal(TupleTableSlot *slot1,
+                                 TupleTableSlot *slot2,
+                                 int numCols,
+                                 AttrNumber *matchColIdx,
+                                 FmgrInfo *eqfunctions,
+                                 MemoryContext evalContext)
+{
+       MemoryContext oldContext;
+       bool            result;
+       int                     i;
+
+       /* Reset and switch into the temp context. */
+       MemoryContextReset(evalContext);
+       oldContext = MemoryContextSwitchTo(evalContext);
+
+       /*
+        * We cannot report a match without checking all the fields, but we can
+        * report a non-match as soon as we find unequal fields.  So, start
+        * comparing at the last field (least significant sort key). That's the
+        * most likely to be different if we are dealing with sorted input.
+        */
+       result = false;
+
+       for (i = numCols; --i >= 0;)
+       {
+               AttrNumber      att = matchColIdx[i];
+               Datum           attr1,
+                                       attr2;
+               bool            isNull1,
+                                       isNull2;
+
+               attr1 = slot_getattr(slot1, att, &isNull1);
+
+               if (isNull1)
+                       continue;                       /* can't prove anything here */
+
+               attr2 = slot_getattr(slot2, att, &isNull2);
+
+               if (isNull2)
+                       continue;                       /* can't prove anything here */
+
+               /* Apply the type-specific equality function */
+
+               if (!DatumGetBool(FunctionCall2(&eqfunctions[i],
+                                                                               attr1, attr2)))
+               {
+                       result = true;          /* they are unequal */
+                       break;
+               }
+       }
+
+       MemoryContextSwitchTo(oldContext);
+
+       return result;
+}
+
 /*
  * findPartialMatch: does the hashtable contain an entry that is not
  * provably distinct from the tuple?
@@ -588,8 +705,10 @@ findPartialMatch(TupleHashTable hashtable, TupleTableSlot *slot,
        TupleHashEntry entry;
 
        InitTupleHashIterator(hashtable, &hashiter);
-       while ((entry = ScanTupleHashTable(&hashiter)) != NULL)
+       while ((entry = ScanTupleHashTable(hashtable, &hashiter)) != NULL)
        {
+               CHECK_FOR_INTERRUPTS();
+
                ExecStoreMinimalTuple(entry->firstTuple, hashtable->tableslot, false);
                if (!execTuplesUnequal(slot, hashtable->tableslot,
                                                           numCols, keyColIdx,
@@ -660,16 +779,18 @@ ExecInitSubPlan(SubPlan *subplan, PlanState *parent)
        SubPlanState *sstate = makeNode(SubPlanState);
        EState     *estate = parent->state;
 
-       sstate->xprstate.evalfunc = (ExprStateEvalFunc) ExecSubPlan;
-       sstate->xprstate.expr = (Expr *) subplan;
+       sstate->subplan = subplan;
 
        /* Link the SubPlanState to already-initialized subplan */
        sstate->planstate = (PlanState *) list_nth(estate->es_subplanstates,
                                                                                           subplan->plan_id - 1);
 
+       /* ... and to its parent's state */
+       sstate->parent = parent;
+
        /* Initialize subexpressions */
        sstate->testexpr = ExecInitExpr((Expr *) subplan->testexpr, parent);
-       sstate->args = (List *) ExecInitExpr((Expr *) subplan->args, parent);
+       sstate->args = ExecInitExprList(subplan->args, parent);
 
        /*
         * initialize my state
@@ -684,21 +805,23 @@ ExecInitSubPlan(SubPlan *subplan, PlanState *parent)
        sstate->hashtempcxt = NULL;
        sstate->innerecontext = NULL;
        sstate->keyColIdx = NULL;
+       sstate->tab_eq_funcoids = NULL;
        sstate->tab_hash_funcs = NULL;
        sstate->tab_eq_funcs = NULL;
        sstate->lhs_hash_funcs = NULL;
        sstate->cur_eq_funcs = NULL;
 
        /*
-        * If this plan is un-correlated or undirect correlated one and want to
-        * set params for parent plan then mark parameters as needing evaluation.
+        * If this is an initplan or MULTIEXPR subplan, it has output parameters
+        * that the parent plan will use, so mark those parameters as needing
+        * evaluation.  We don't actually run the subplan until we first need one
+        * of its outputs.
         *
         * A CTE subplan's output parameter is never to be evaluated in the normal
         * way, so skip this in that case.
         *
-        * Note that in the case of un-correlated subqueries we don't care about
-        * setting parent->chgParam here: indices take care about it, for others -
-        * it doesn't matter...
+        * Note that we don't set parent->chgParam here: the parent plan hasn't
+        * been run yet, so no need to force it to re-run.
         */
        if (subplan->setParam != NIL && subplan->subLinkType != CTE_SUBLINK)
        {
@@ -721,29 +844,24 @@ ExecInitSubPlan(SubPlan *subplan, PlanState *parent)
        {
                int                     ncols,
                                        i;
-               TupleDesc       tupDesc;
+               TupleDesc       tupDescLeft;
+               TupleDesc       tupDescRight;
                TupleTableSlot *slot;
                List       *oplist,
                                   *lefttlist,
-                                  *righttlist,
-                                  *leftptlist,
-                                  *rightptlist;
+                                  *righttlist;
                ListCell   *l;
 
                /* We need a memory context to hold the hash table(s) */
                sstate->hashtablecxt =
                        AllocSetContextCreate(CurrentMemoryContext,
                                                                  "Subplan HashTable Context",
-                                                                 ALLOCSET_DEFAULT_MINSIZE,
-                                                                 ALLOCSET_DEFAULT_INITSIZE,
-                                                                 ALLOCSET_DEFAULT_MAXSIZE);
+                                                                 ALLOCSET_DEFAULT_SIZES);
                /* and a small one for the hash tables to use as temp storage */
                sstate->hashtempcxt =
                        AllocSetContextCreate(CurrentMemoryContext,
                                                                  "Subplan HashTable Temp Context",
-                                                                 ALLOCSET_SMALL_MINSIZE,
-                                                                 ALLOCSET_SMALL_INITSIZE,
-                                                                 ALLOCSET_SMALL_MAXSIZE);
+                                                                 ALLOCSET_SMALL_SIZES);
                /* and a short-lived exprcontext for function evaluation */
                sstate->innerecontext = CreateExprContext(estate);
                /* Silly little array of column numbers 1..n */
@@ -758,36 +876,34 @@ ExecInitSubPlan(SubPlan *subplan, PlanState *parent)
                 * use the sub-select's output tuples directly, but that is not the
                 * case if we had to insert any run-time coercions of the sub-select's
                 * output datatypes; anyway this avoids storing any resjunk columns
-                * that might be in the sub-select's output.) Run through the
+                * that might be in the sub-select's output.)  Run through the
                 * combining expressions to build tlists for the lefthand and
-                * righthand sides.  We need both the ExprState list (for ExecProject)
-                * and the underlying parse Exprs (for ExecTypeFromTL).
+                * righthand sides.
                 *
                 * We also extract the combining operators themselves to initialize
                 * the equality and hashing functions for the hash tables.
                 */
-               if (IsA(sstate->testexpr->expr, OpExpr))
+               if (IsA(subplan->testexpr, OpExpr))
                {
                        /* single combining operator */
-                       oplist = list_make1(sstate->testexpr);
+                       oplist = list_make1(subplan->testexpr);
                }
-               else if (and_clause((Node *) sstate->testexpr->expr))
+               else if (is_andclause(subplan->testexpr))
                {
                        /* multiple combining operators */
-                       Assert(IsA(sstate->testexpr, BoolExprState));
-                       oplist = ((BoolExprState *) sstate->testexpr)->args;
+                       oplist = castNode(BoolExpr, subplan->testexpr)->args;
                }
                else
                {
                        /* shouldn't see anything else in a hashable subplan */
                        elog(ERROR, "unrecognized testexpr type: %d",
-                                (int) nodeTag(sstate->testexpr->expr));
+                                (int) nodeTag(subplan->testexpr));
                        oplist = NIL;           /* keep compiler quiet */
                }
                Assert(list_length(oplist) == ncols);
 
                lefttlist = righttlist = NIL;
-               leftptlist = rightptlist = NIL;
+               sstate->tab_eq_funcoids = (Oid *) palloc(ncols * sizeof(Oid));
                sstate->tab_hash_funcs = (FmgrInfo *) palloc(ncols * sizeof(FmgrInfo));
                sstate->tab_eq_funcs = (FmgrInfo *) palloc(ncols * sizeof(FmgrInfo));
                sstate->lhs_hash_funcs = (FmgrInfo *) palloc(ncols * sizeof(FmgrInfo));
@@ -795,49 +911,33 @@ ExecInitSubPlan(SubPlan *subplan, PlanState *parent)
                i = 1;
                foreach(l, oplist)
                {
-                       FuncExprState *fstate = (FuncExprState *) lfirst(l);
-                       OpExpr     *opexpr = (OpExpr *) fstate->xprstate.expr;
-                       ExprState  *exstate;
+                       OpExpr     *opexpr = lfirst_node(OpExpr, l);
                        Expr       *expr;
                        TargetEntry *tle;
-                       GenericExprState *tlestate;
                        Oid                     rhs_eq_oper;
                        Oid                     left_hashfn;
                        Oid                     right_hashfn;
 
-                       Assert(IsA(fstate, FuncExprState));
-                       Assert(IsA(opexpr, OpExpr));
-                       Assert(list_length(fstate->args) == 2);
+                       Assert(list_length(opexpr->args) == 2);
 
                        /* Process lefthand argument */
-                       exstate = (ExprState *) linitial(fstate->args);
-                       expr = exstate->expr;
+                       expr = (Expr *) linitial(opexpr->args);
                        tle = makeTargetEntry(expr,
                                                                  i,
                                                                  NULL,
                                                                  false);
-                       tlestate = makeNode(GenericExprState);
-                       tlestate->xprstate.expr = (Expr *) tle;
-                       tlestate->xprstate.evalfunc = NULL;
-                       tlestate->arg = exstate;
-                       lefttlist = lappend(lefttlist, tlestate);
-                       leftptlist = lappend(leftptlist, tle);
+                       lefttlist = lappend(lefttlist, tle);
 
                        /* Process righthand argument */
-                       exstate = (ExprState *) lsecond(fstate->args);
-                       expr = exstate->expr;
+                       expr = (Expr *) lsecond(opexpr->args);
                        tle = makeTargetEntry(expr,
                                                                  i,
                                                                  NULL,
                                                                  false);
-                       tlestate = makeNode(GenericExprState);
-                       tlestate->xprstate.expr = (Expr *) tle;
-                       tlestate->xprstate.evalfunc = NULL;
-                       tlestate->arg = exstate;
-                       righttlist = lappend(righttlist, tlestate);
-                       rightptlist = lappend(rightptlist, tle);
+                       righttlist = lappend(righttlist, tle);
 
                        /* Lookup the equality function (potentially cross-type) */
+                       sstate->tab_eq_funcoids[i - 1] = opexpr->opfuncid;
                        fmgr_info(opexpr->opfuncid, &sstate->cur_eq_funcs[i - 1]);
                        fmgr_info_set_expr((Node *) opexpr, &sstate->cur_eq_funcs[i - 1]);
 
@@ -867,21 +967,33 @@ ExecInitSubPlan(SubPlan *subplan, PlanState *parent)
                 * (hack alert!).  The righthand expressions will be evaluated in our
                 * own innerecontext.
                 */
-               tupDesc = ExecTypeFromTL(leftptlist, false);
-               slot = ExecInitExtraTupleSlot(estate);
-               ExecSetSlotDescriptor(slot, tupDesc);
+               tupDescLeft = ExecTypeFromTL(lefttlist);
+               slot = ExecInitExtraTupleSlot(estate, tupDescLeft, &TTSOpsVirtual);
                sstate->projLeft = ExecBuildProjectionInfo(lefttlist,
                                                                                                   NULL,
                                                                                                   slot,
+                                                                                                  parent,
                                                                                                   NULL);
 
-               tupDesc = ExecTypeFromTL(rightptlist, false);
-               slot = ExecInitExtraTupleSlot(estate);
-               ExecSetSlotDescriptor(slot, tupDesc);
+               sstate->descRight = tupDescRight = ExecTypeFromTL(righttlist);
+               slot = ExecInitExtraTupleSlot(estate, tupDescRight, &TTSOpsVirtual);
                sstate->projRight = ExecBuildProjectionInfo(righttlist,
                                                                                                        sstate->innerecontext,
                                                                                                        slot,
+                                                                                                       sstate->planstate,
                                                                                                        NULL);
+
+               /*
+                * Create comparator for lookups of rows in the table (potentially
+                * across-type comparison).
+                */
+               sstate->cur_eq_comp = ExecBuildGroupingEqual(tupDescLeft, tupDescRight,
+                                                                                                        &TTSOpsVirtual, &TTSOpsMinimalTuple,
+                                                                                                        ncols,
+                                                                                                        sstate->keyColIdx,
+                                                                                                        sstate->tab_eq_funcoids,
+                                                                                                        parent);
+
        }
 
        return sstate;
@@ -890,27 +1002,41 @@ ExecInitSubPlan(SubPlan *subplan, PlanState *parent)
 /* ----------------------------------------------------------------
  *             ExecSetParamPlan
  *
- *             Executes an InitPlan subplan and sets its output parameters.
+ *             Executes a subplan and sets its output parameters.
  *
  * This is called from ExecEvalParamExec() when the value of a PARAM_EXEC
  * parameter is requested and the param's execPlan field is set (indicating
- * that the param has not yet been evaluated). This allows lazy evaluation
+ * that the param has not yet been evaluated).  This allows lazy evaluation
  * of initplans: we don't run the subplan until/unless we need its output.
  * Note that this routine MUST clear the execPlan fields of the plan's
  * output parameters after evaluating them!
+ *
+ * The results of this function are stored in the EState associated with the
+ * ExprContext (particularly, its ecxt_param_exec_vals); any pass-by-ref
+ * result Datums are allocated in the EState's per-query memory.  The passed
+ * econtext can be any ExprContext belonging to that EState; which one is
+ * important only to the extent that the ExprContext's per-tuple memory
+ * context is used to evaluate any parameters passed down to the subplan.
+ * (Thus in principle, the shorter-lived the ExprContext the better, since
+ * that data isn't needed after we return.  In practice, because initplan
+ * parameters are never more complex than Vars, Aggrefs, etc, evaluating them
+ * currently never leaks any memory anyway.)
  * ----------------------------------------------------------------
  */
 void
 ExecSetParamPlan(SubPlanState *node, ExprContext *econtext)
 {
-       SubPlan    *subplan = (SubPlan *) node->xprstate.expr;
+       SubPlan    *subplan = node->subplan;
        PlanState  *planstate = node->planstate;
        SubLinkType subLinkType = subplan->subLinkType;
+       EState     *estate = planstate->state;
+       ScanDirection dir = estate->es_direction;
        MemoryContext oldcontext;
        TupleTableSlot *slot;
+       ListCell   *pvar;
        ListCell   *l;
        bool            found = false;
-       ArrayBuildState *astate = NULL;
+       ArrayBuildStateAny *astate = NULL;
 
        if (subLinkType == ANY_SUBLINK ||
                subLinkType == ALL_SUBLINK)
@@ -918,11 +1044,42 @@ ExecSetParamPlan(SubPlanState *node, ExprContext *econtext)
        if (subLinkType == CTE_SUBLINK)
                elog(ERROR, "CTE subplans should not be executed via ExecSetParamPlan");
 
+       /*
+        * Enforce forward scan direction regardless of caller. It's hard but not
+        * impossible to get here in backward scan, so make it work anyway.
+        */
+       estate->es_direction = ForwardScanDirection;
+
+       /* Initialize ArrayBuildStateAny in caller's context, if needed */
+       if (subLinkType == ARRAY_SUBLINK)
+               astate = initArrayResultAny(subplan->firstColType,
+                                                                       CurrentMemoryContext, true);
+
        /*
         * Must switch to per-query memory context.
         */
        oldcontext = MemoryContextSwitchTo(econtext->ecxt_per_query_memory);
 
+       /*
+        * Set Params of this plan from parent plan correlation values. (Any
+        * calculation we have to do is done in the parent econtext, since the
+        * Param values don't need to have per-query lifetime.)  Currently, we
+        * expect only MULTIEXPR_SUBLINK plans to have any correlation values.
+        */
+       Assert(subplan->parParam == NIL || subLinkType == MULTIEXPR_SUBLINK);
+       Assert(list_length(subplan->parParam) == list_length(node->args));
+
+       forboth(l, subplan->parParam, pvar, node->args)
+       {
+               int                     paramid = lfirst_int(l);
+               ParamExecData *prm = &(econtext->ecxt_param_exec_vals[paramid]);
+
+               prm->value = ExecEvalExprSwitchContext((ExprState *) lfirst(pvar),
+                                                                                          econtext,
+                                                                                          &(prm->isnull));
+               planstate->chgParam = bms_add_member(planstate->chgParam, paramid);
+       }
+
        /*
         * Run the plan.  (If it needs to be rescanned, the first ExecProcNode
         * call will take care of that.)
@@ -954,16 +1111,17 @@ ExecSetParamPlan(SubPlanState *node, ExprContext *econtext)
 
                        found = true;
                        /* stash away current value */
-                       Assert(subplan->firstColType == tdesc->attrs[0]->atttypid);
+                       Assert(subplan->firstColType == TupleDescAttr(tdesc, 0)->atttypid);
                        dvalue = slot_getattr(slot, 1, &disnull);
-                       astate = accumArrayResult(astate, dvalue, disnull,
-                                                                         subplan->firstColType, oldcontext);
+                       astate = accumArrayResultAny(astate, dvalue, disnull,
+                                                                                subplan->firstColType, oldcontext);
                        /* keep scanning subplan to collect all values */
                        continue;
                }
 
                if (found &&
                        (subLinkType == EXPR_SUBLINK ||
+                        subLinkType == MULTIEXPR_SUBLINK ||
                         subLinkType == ROWCOMPARE_SUBLINK))
                        ereport(ERROR,
                                        (errcode(ERRCODE_CARDINALITY_VIOLATION),
@@ -979,7 +1137,7 @@ ExecSetParamPlan(SubPlanState *node, ExprContext *econtext)
                 */
                if (node->curTuple)
                        heap_freetuple(node->curTuple);
-               node->curTuple = ExecCopySlotTuple(slot);
+               node->curTuple = ExecCopySlotHeapTuple(slot);
 
                /*
                 * Now set all the setParam params from the columns of the tuple
@@ -1009,14 +1167,9 @@ ExecSetParamPlan(SubPlanState *node, ExprContext *econtext)
                 */
                if (node->curArray != PointerGetDatum(NULL))
                        pfree(DatumGetPointer(node->curArray));
-               if (astate != NULL)
-                       node->curArray = makeArrayResult(astate,
-                                                                                        econtext->ecxt_per_query_memory);
-               else
-               {
-                       MemoryContextSwitchTo(econtext->ecxt_per_query_memory);
-                       node->curArray = PointerGetDatum(construct_empty_array(subplan->firstColType));
-               }
+               node->curArray = makeArrayResultAny(astate,
+                                                                                       econtext->ecxt_per_query_memory,
+                                                                                       true);
                prm->execPlan = NULL;
                prm->value = node->curArray;
                prm->isnull = false;
@@ -1035,6 +1188,7 @@ ExecSetParamPlan(SubPlanState *node, ExprContext *econtext)
                }
                else
                {
+                       /* For other sublink types, set all the output params to NULL */
                        foreach(l, subplan->setParam)
                        {
                                int                     paramid = lfirst_int(l);
@@ -1048,6 +1202,40 @@ ExecSetParamPlan(SubPlanState *node, ExprContext *econtext)
        }
 
        MemoryContextSwitchTo(oldcontext);
+
+       /* restore scan direction */
+       estate->es_direction = dir;
+}
+
+/*
+ * ExecSetParamPlanMulti
+ *
+ * Apply ExecSetParamPlan to evaluate any not-yet-evaluated initplan output
+ * parameters whose ParamIDs are listed in "params".  Any listed params that
+ * are not initplan outputs are ignored.
+ *
+ * As with ExecSetParamPlan, any ExprContext belonging to the current EState
+ * can be used, but in principle a shorter-lived ExprContext is better than a
+ * longer-lived one.
+ */
+void
+ExecSetParamPlanMulti(const Bitmapset *params, ExprContext *econtext)
+{
+       int                     paramid;
+
+       paramid = -1;
+       while ((paramid = bms_next_member(params, paramid)) >= 0)
+       {
+               ParamExecData *prm = &(econtext->ecxt_param_exec_vals[paramid]);
+
+               if (prm->execPlan != NULL)
+               {
+                       /* Parameter not evaluated yet, so go do it */
+                       ExecSetParamPlan(prm->execPlan, econtext);
+                       /* ExecSetParamPlan should have processed this param... */
+                       Assert(prm->execPlan == NULL);
+               }
+       }
 }
 
 /*
@@ -1057,7 +1245,7 @@ void
 ExecReScanSetParamPlan(SubPlanState *node, PlanState *parent)
 {
        PlanState  *planstate = node->planstate;
-       SubPlan    *subplan = (SubPlan *) node->xprstate.expr;
+       SubPlan    *subplan = node->subplan;
        EState     *estate = parent->state;
        ListCell   *l;
 
@@ -1108,21 +1296,27 @@ ExecInitAlternativeSubPlan(AlternativeSubPlan *asplan, PlanState *parent)
        SubPlan    *subplan2;
        Cost            cost1;
        Cost            cost2;
+       ListCell   *lc;
 
-       asstate->xprstate.evalfunc = (ExprStateEvalFunc) ExecAlternativeSubPlan;
-       asstate->xprstate.expr = (Expr *) asplan;
+       asstate->subplan = asplan;
 
        /*
         * Initialize subplans.  (Can we get away with only initializing the one
         * we're going to use?)
         */
-       asstate->subplans = (List *) ExecInitExpr((Expr *) asplan->subplans,
-                                                                                         parent);
+       foreach(lc, asplan->subplans)
+       {
+               SubPlan    *sp = lfirst_node(SubPlan, lc);
+               SubPlanState *sps = ExecInitSubPlan(sp, parent);
+
+               asstate->subplans = lappend(asstate->subplans, sps);
+               parent->subPlan = lappend(parent->subPlan, sps);
+       }
 
        /*
         * Select the one to be used.  For this, we need an estimate of the number
         * of executions of the subplan.  We use the number of output rows
-        * expected from the parent plan node.  This is a good estimate if we are
+        * expected from the parent plan node.  This is a good estimate if we are
         * in the parent's targetlist, and an underestimate (but probably not by
         * more than a factor of 2) if we are in the qual.
         */
@@ -1155,20 +1349,14 @@ ExecInitAlternativeSubPlan(AlternativeSubPlan *asplan, PlanState *parent)
  * Note: in future we might consider changing to different subplans on the
  * fly, in case the original rowcount estimate turns out to be way off.
  */
-static Datum
+Datum
 ExecAlternativeSubPlan(AlternativeSubPlanState *node,
                                           ExprContext *econtext,
-                                          bool *isNull,
-                                          ExprDoneCond *isDone)
+                                          bool *isNull)
 {
        /* Just pass control to the active subplan */
-       SubPlanState *activesp = (SubPlanState *) list_nth(node->subplans,
-                                                                                                          node->active);
-
-       Assert(IsA(activesp, SubPlanState));
+       SubPlanState *activesp = list_nth_node(SubPlanState,
+                                                                                  node->subplans, node->active);
 
-       return ExecSubPlan(activesp,
-                                          econtext,
-                                          isNull,
-                                          isDone);
+       return ExecSubPlan(activesp, econtext, isNull);
 }