Thank you for pointing out. I missed the warning.
> There is a new compiler warning:
>
> setrefs.c: In function ‘set_plan_refs’:
> setrefs.c:782:7: warning: initialization from incompatible pointer type
> [enabled by default]
Added explicit cast there and rebased to current master.
Checked no new warning by this patch.
make check succeeded at both $(src) and $(src)/src/test.
regards,
--
Kyotaro Horiguchi
NTT Open Source Software Center
diff --git a/src/backend/optimizer/plan/planner.c b/src/backend/optimizer/plan/planner.c
index d8aa35d..86abdf6 100644
--- a/src/backend/optimizer/plan/planner.c
+++ b/src/backend/optimizer/plan/planner.c
@@ -1063,15 +1063,6 @@ grouping_planner(PlannerInfo *root, double tuple_fraction)
List *set_sortclauses;
/*
- * If there's a top-level ORDER BY, assume we have to fetch all the
- * tuples. This might be too simplistic given all the hackery below
- * to possibly avoid the sort; but the odds of accurate estimates here
- * are pretty low anyway.
- */
- if (parse->sortClause)
- tuple_fraction = 0.0;
-
- /*
* Construct the plan for set operations. The result will not need
* any work except perhaps a top-level sort and/or LIMIT. Note that
* any special work for recursive unions is the responsibility of
diff --git a/src/backend/optimizer/plan/setrefs.c b/src/backend/optimizer/plan/setrefs.c
index b78d727..c6abe18 100644
--- a/src/backend/optimizer/plan/setrefs.c
+++ b/src/backend/optimizer/plan/setrefs.c
@@ -778,9 +778,26 @@ set_plan_refs(PlannerInfo *root, Plan *plan, int rtoffset)
Assert(splan->plan.qual == NIL);
foreach(l, splan->appendplans)
{
- lfirst(l) = set_plan_refs(root,
- (Plan *) lfirst(l),
- rtoffset);
+ Append *newp =
+ (Append *)set_plan_refs(root,
+ (Plan *) lfirst(l),
+ rtoffset);
+ /*
+ * UNION on inherited tables may create directly nested
+ * Appends in plan tree. This structure can be flatten by
+ * taking grandchildren into parent.
+ */
+ if (IsA(newp, Append) &&
+ list_length(newp->appendplans) > 0)
+ {
+ ListCell *plc = list_head(newp->appendplans);
+ lfirst(l) = lfirst(plc);
+ for_each_cell(plc, lnext(plc))
+ l = lappend_cell(splan->appendplans,
+ l, lfirst(plc));
+ }
+ else
+ lfirst(l) = newp;
}
}
break;
diff --git a/src/backend/optimizer/prep/prepunion.c b/src/backend/optimizer/prep/prepunion.c
index e249628..e8a78a7 100644
--- a/src/backend/optimizer/prep/prepunion.c
+++ b/src/backend/optimizer/prep/prepunion.c
@@ -29,6 +29,7 @@
#include "postgres.h"
#include <limits.h>
+#include <math.h>
#include "access/heapam.h"
#include "access/htup_details.h"
@@ -60,6 +61,7 @@ typedef struct
static Plan *recurse_set_operations(Node *setOp, PlannerInfo *root,
double tuple_fraction,
List *colTypes, List *colCollations,
+ List *groupClauses,
bool junkOK,
int flag, List *refnames_tlist,
List **sortClauses, double *pNumGroups);
@@ -78,7 +80,8 @@ static Plan *generate_nonunion_plan(SetOperationStmt *op, PlannerInfo *root,
static List *recurse_union_children(Node *setOp, PlannerInfo *root,
double tuple_fraction,
SetOperationStmt *top_union,
- List *refnames_tlist);
+ List *refnames_tlist,
+ List **child_sortclause);
static Plan *make_union_unique(SetOperationStmt *op, Plan *plan,
PlannerInfo *root, double tuple_fraction,
List **sortClauses);
@@ -97,7 +100,8 @@ static List *generate_append_tlist(List *colTypes, List *colCollations,
bool flag,
List *input_plans,
List *refnames_tlist);
-static List *generate_setop_grouplist(SetOperationStmt *op, List *targetlist);
+static List *generate_setop_grouplist(List *groupClauses, List *targetlist,
+ List *sortClauses);
static void expand_inherited_rtentry(PlannerInfo *root, RangeTblEntry *rte,
Index rti);
static void make_inh_translation_list(Relation oldrelation,
@@ -152,6 +156,15 @@ plan_set_operations(PlannerInfo *root, double tuple_fraction,
Assert(parse->distinctClause == NIL);
/*
+ * If there's a top-level ORDER BY, assume we have to fetch all the tuples
+ * except for UNION. This might be too simplistic given all the hackery
+ * below to possibly avoid the sort; but the odds of accurate estimates
+ * here are pretty low anyway.
+ */
+ if (parse->sortClause && topop->op != SETOP_UNION)
+ tuple_fraction = 0.0;
+
+ /*
* We'll need to build RelOptInfos for each of the leaf subqueries, which
* are RTE_SUBQUERY rangetable entries in this Query. Prepare the index
* arrays for that.
@@ -186,18 +199,49 @@ plan_set_operations(PlannerInfo *root, double tuple_fraction,
*/
return recurse_set_operations((Node *) topop, root, tuple_fraction,
topop->colTypes, topop->colCollations,
+ topop->groupClauses,
true, -1,
leftmostQuery->targetList,
sortClauses, NULL);
}
/*
+ * save_plannerglobal
+ *
+ * save planner global to allow multiple calls of subquery_planner at the same
+ * global status. This is done apartly from copyObject so as to do medium
+ * shallow copying.
+ */
+static PlannerGlobal *
+save_plannerglobal(const PlannerGlobal *in)
+{
+ PlannerGlobal *save = makeNode(PlannerGlobal);
+
+ save->boundParams = in->boundParams;
+ save->subplans = list_copy(in->subplans);
+ save->subroots = list_copy(in->subroots);
+ save->rewindPlanIDs = bms_copy(in->rewindPlanIDs);
+ save->finalrtable = list_copy(in->finalrtable);
+ save->finalrowmarks = list_copy(in->finalrowmarks);
+ save->resultRelations = list_copy(in->resultRelations);
+ save->relationOids = list_copy(in->relationOids);
+ save->invalItems = list_copy(in->invalItems);
+ save->nParamExec = in->nParamExec;
+ save->lastPHId = in->lastPHId;
+ save->lastRowMarkId = in->lastRowMarkId;
+ save->transientPlan = in->transientPlan;
+
+ return save;
+}
+
+/*
* recurse_set_operations
* Recursively handle one step in a tree of set operations
*
* tuple_fraction: fraction of tuples we expect to retrieve from node
* colTypes: OID list of set-op's result column datatypes
* colCollations: OID list of set-op's result column collations
+ * groupClauses: parent setop's grouping clause.
* junkOK: if true, child resjunk columns may be left in the result
* flag: if >= 0, add a resjunk output column indicating value of flag
* refnames_tlist: targetlist to take column names from
@@ -215,6 +259,7 @@ static Plan *
recurse_set_operations(Node *setOp, PlannerInfo *root,
double tuple_fraction,
List *colTypes, List *colCollations,
+ List *groupClauses,
bool junkOK,
int flag, List *refnames_tlist,
List **sortClauses, double *pNumGroups)
@@ -223,14 +268,21 @@ recurse_set_operations(Node *setOp, PlannerInfo *root,
{
RangeTblRef *rtr = (RangeTblRef *) setOp;
RangeTblEntry *rte = root->simple_rte_array[rtr->rtindex];
- Query *subquery = rte->subquery;
+ Query *subquery = rte->subquery,
+ *pdquery;
RelOptInfo *rel;
- PlannerInfo *subroot;
+ PlannerInfo *subroot,
+ *pdsubroot; /* 'pd' comes from 'Pushed Down' */
+ PlannerGlobal *pdglob;
Plan *subplan,
- *plan;
+ *plan,
+ *pdplan;
+ bool try_pushdown = false;
Assert(subquery != NULL);
+ *sortClauses = NIL;
+
/*
* We need to build a RelOptInfo for each leaf subquery. This isn't
* used for anything here, but it carries the subroot data structures
@@ -243,12 +295,125 @@ recurse_set_operations(Node *setOp, PlannerInfo *root,
/*
* Generate plan for primitive subquery
+ *
+ * Consider whether ORDER BY or groupings of the parent set operation
+ * can be pushed down onto this subquery.
*/
+
+ /*
+ * Consider whether ORDER BY or groupings of the parent set operation
+ * can be pushed down onto this subquery.
+ */
+ if(root->parse->sortClause && !subquery->sortClause &&
+ tuple_fraction >= 1)
+ {
+ ListCell *lcs, *lcd;
+ int refno = 1;
+
+ /*
+ * Check if the sort cluase of the root can be applied on this
+ * subquery. All non-junk tlist items shoud be simple Var and
+ * their types match and ressortgroupref is ordered in their
+ * appearance order.
+ */
+ try_pushdown = true;
+ forboth(lcs, root->parse->targetList, lcd, subquery->targetList)
+ {
+ TargetEntry *ste = (TargetEntry*) lfirst(lcs);
+ TargetEntry *dte = (TargetEntry*) lfirst(lcd);
+ Node *sexpr = (Node*)ste->expr;
+ Node *dexpr = (Node*)dte->expr;
+
+ if (ste->resjunk && dte->resjunk) continue;
+
+ if (ste->resjunk != dte->resjunk ||
+ !IsA(sexpr, Var) || !IsA(dexpr, Var) ||
+ exprType(sexpr) != exprType(dexpr) ||
+ (root->parse->sortClause &&
+ ste->ressortgroupref != refno++))
+ {
+ try_pushdown = false;
+ break;
+ }
+ }
+ }
+
+ if (try_pushdown)
+ {
+ pdquery = copyObject(subquery);
+
+ if (!pdquery->sortClause)
+ {
+ ListCell *lcs, *lcd;
+
+ pdquery->sortClause = root->parse->sortClause;
+
+ forboth(lcs, root->parse->targetList,
+ lcd, pdquery->targetList)
+ {
+ TargetEntry *ste = (TargetEntry*) lfirst(lcs);
+ TargetEntry *dte = (TargetEntry*) lfirst(lcd);
+ dte->ressortgroupref = ste->ressortgroupref;
+ }
+ }
+
+ /*
+ * Pushing down groupings. Set operations doesn't accept
+ * distinct clauses.
+ */
+ if (!pdquery->setOperations &&
+ !pdquery->distinctClause && groupClauses)
+
+ pdquery->distinctClause =
+ generate_setop_grouplist(groupClauses,
+ pdquery->targetList,
+ pdquery->sortClause);
+
+ if (tuple_fraction >= 1 &&
+ !pdquery->limitCount && !pdquery->limitOffset)
+ pdquery->limitCount =
+ (Node*)makeConst(INT8OID, -1, InvalidOid, sizeof(int64),
+ Int64GetDatum(tuple_fraction),
+ false, FLOAT8PASSBYVAL);
+
+ pdglob = save_plannerglobal(root->glob);
+ }
+
subplan = subquery_planner(root->glob, subquery,
root,
false, tuple_fraction,
&subroot);
+ if (try_pushdown)
+ {
+ pdplan = subquery_planner(pdglob, pdquery,
+ root,
+ false, tuple_fraction,
+ &pdsubroot);
+
+ if (pdplan->total_cost < subplan->total_cost)
+ {
+ subplan = pdplan;
+ subroot = pdsubroot;
+ /*
+ * Glob cannot be moved because this is referred to from
+ * many places by its address. So set the address of the
+ * original glob to subroot, then copy new values there.
+ */
+ subroot->glob = root->glob;
+ *root->glob = *pdglob;
+ }
+ }
+
+ /*
+ * This plan is sorted on sortClause if any, else sorted
+ * on distinctClause.
+ */
+ if (subquery->sortClause)
+ *sortClauses = subquery->sortClause;
+ else
+ *sortClauses = subquery->distinctClause;
+
/* Save subroot and subplan in RelOptInfo for setrefs.c */
rel->subplan = subplan;
rel->subroot = subroot;
@@ -290,12 +455,6 @@ recurse_set_operations(Node *setOp, PlannerInfo *root,
rtr->rtindex,
subplan);
- /*
- * We don't bother to determine the subquery's output ordering since
- * it won't be reflected in the set-op result anyhow.
- */
- *sortClauses = NIL;
-
return plan;
}
else if (IsA(setOp, SetOperationStmt))
@@ -379,12 +538,14 @@ generate_recursion_plan(SetOperationStmt *setOp, PlannerInfo *root,
*/
lplan = recurse_set_operations(setOp->larg, root, tuple_fraction,
setOp->colTypes, setOp->colCollations,
+ setOp->groupClauses,
false, -1,
refnames_tlist, sortClauses, NULL);
/* The right plan will want to look at the left one ... */
root->non_recursive_plan = lplan;
rplan = recurse_set_operations(setOp->rarg, root, tuple_fraction,
setOp->colTypes, setOp->colCollations,
+ setOp->groupClauses,
false, -1,
refnames_tlist, sortClauses, NULL);
root->non_recursive_plan = NULL;
@@ -409,7 +570,8 @@ generate_recursion_plan(SetOperationStmt *setOp, PlannerInfo *root,
double dNumGroups;
/* Identify the grouping semantics */
- groupList = generate_setop_grouplist(setOp, tlist);
+ groupList =
+ generate_setop_grouplist(setOp->groupClauses, tlist, NULL);
/* We only support hashing here */
if (!grouping_is_hashable(groupList))
@@ -452,20 +614,7 @@ generate_union_plan(SetOperationStmt *op, PlannerInfo *root,
List *planlist;
List *tlist;
Plan *plan;
-
- /*
- * If plain UNION, tell children to fetch all tuples.
- *
- * Note: in UNION ALL, we pass the top-level tuple_fraction unmodified to
- * each arm of the UNION ALL. One could make a case for reducing the
- * tuple fraction for later arms (discounting by the expected size of the
- * earlier arms' results) but it seems not worth the trouble. The normal
- * case where tuple_fraction isn't already zero is a LIMIT at top level,
- * and passing it down as-is is usually enough to get the desired result
- * of preferring fast-start plans.
- */
- if (!op->all)
- tuple_fraction = 0.0;
+ List *lsort, *rsort;
/*
* If any of my children are identical UNION nodes (same op, all-flag, and
@@ -475,34 +624,99 @@ generate_union_plan(SetOperationStmt *op, PlannerInfo *root,
*/
planlist = list_concat(recurse_union_children(op->larg, root,
tuple_fraction,
- op, refnames_tlist),
+ op, refnames_tlist,
+ &lsort),
recurse_union_children(op->rarg, root,
tuple_fraction,
- op, refnames_tlist));
+ op, refnames_tlist,
+ &rsort));
/*
- * Generate tlist for Append plan node.
+ * Generate tlist for Append/MergeAppend plan node.
*
- * The tlist for an Append plan isn't important as far as the Append is
- * concerned, but we must make it look real anyway for the benefit of the
- * next plan level up.
+ * The tlist for an Append/MergeAppend plan isn't important as far as the
+ * they are concerned, but we must make it look real anyway for the
+ * benefit of the next plan level up.
*/
tlist = generate_append_tlist(op->colTypes, op->colCollations, false,
planlist, refnames_tlist);
- /*
- * Append the child results together.
- */
- plan = (Plan *) make_append(planlist, tlist);
-
- /*
- * For UNION ALL, we just need the Append plan. For UNION, need to add
- * node(s) to remove duplicates.
- */
- if (op->all)
- *sortClauses = NIL; /* result of UNION ALL is always unsorted */
+ if (lsort != NIL && equal(lsort, rsort))
+ {
+ /*
+ * Generate MergeAppend plan if both children are sorted on the same
+ * sort clause or groupClauses.
+ */
+ ListCell *lc, *slc;
+ int i = 0;
+ double total_size;
+ Plan *p;
+ List *distinctClause;
+
+ MergeAppend *node = makeNode(MergeAppend);
+ node->plan.targetlist = tlist;
+ node->plan.qual = NIL;
+ node->plan.lefttree = NULL;
+ node->plan.righttree = NULL;
+ node->mergeplans = planlist;
+ node->numCols = list_length(root->parse->targetList);
+ node->sortColIdx = (AttrNumber*)palloc(sizeof(AttrNumber) * node->numCols);
+ node->sortOperators = (Oid*)palloc(sizeof(Oid) * node->numCols);
+ node->collations = (Oid*)palloc(sizeof(Oid) * node->numCols);
+ node->nullsFirst = (bool*)palloc(sizeof(bool) * node->numCols);
+
+ distinctClause =
+ generate_setop_grouplist(op->groupClauses,
+ node->plan.targetlist,
+ root->parse->sortClause);
+ forboth (slc, distinctClause, lc, node->plan.targetlist)
+ {
+ TargetEntry *te = (TargetEntry*) lfirst(lc);
+ SortGroupClause *sgc = (SortGroupClause *) lfirst(slc);
+
+ Assert(sgc->tleSortGroupRef == te->ressortgroupref);
+ node->sortColIdx[i] = i + 1;
+ node->sortOperators[i] = sgc->sortop;
+ node->collations[i] = exprCollation((Node*)te->expr);
+ node->nullsFirst[i] = sgc->nulls_first;
+ i++;
+ }
+ lc = list_head(node->mergeplans);
+ p = (Plan*) lfirst(lc);
+ node->plan.startup_cost = p->startup_cost;
+ node->plan.total_cost = p->total_cost;
+ node->plan.plan_rows = p->plan_rows;
+ total_size = p->plan_rows * p->plan_width;
+ for_each_cell(lc, lnext(lc))
+ {
+ p = (Plan*) lfirst(lc);
+ node->plan.total_cost += p->total_cost;
+ node->plan.plan_rows += p->plan_rows;
+ total_size += p->plan_rows * p->plan_width;
+ }
+ node->plan.plan_width = rint(total_size / node->plan.plan_rows);
+ *sortClauses = root->parse->sortClause;
+ plan = (Plan*)node;
+ if (!op->all)
+ plan = make_union_unique(op, plan, root, tuple_fraction,
+ &distinctClause);
+ }
else
- plan = make_union_unique(op, plan, root, tuple_fraction, sortClauses);
+ {
+ /*
+ * Append the child results together.
+ */
+ plan = (Plan *) make_append(planlist, tlist);
+
+ /*
+ * For UNION ALL, we just need the Append plan. For UNION, need to
+ * add node(s) to remove duplicates.
+ */
+ *sortClauses = NIL;
+
+ if (!op->all)
+ plan = make_union_unique(op, plan, root, tuple_fraction, sortClauses);
+ }
/*
* Estimate number of groups if caller wants it. For now we just assume
@@ -544,12 +758,14 @@ generate_nonunion_plan(SetOperationStmt *op, PlannerInfo *root,
lplan = recurse_set_operations(op->larg, root,
0.0 /* all tuples needed */ ,
op->colTypes, op->colCollations,
+ op->groupClauses,
false, 0,
refnames_tlist,
&child_sortclauses, &dLeftGroups);
rplan = recurse_set_operations(op->rarg, root,
0.0 /* all tuples needed */ ,
op->colTypes, op->colCollations,
+ op->groupClauses,
false, 1,
refnames_tlist,
&child_sortclauses, &dRightGroups);
@@ -589,7 +805,7 @@ generate_nonunion_plan(SetOperationStmt *op, PlannerInfo *root,
plan = (Plan *) make_append(planlist, tlist);
/* Identify the grouping semantics */
- groupList = generate_setop_grouplist(op, tlist);
+ groupList = generate_setop_grouplist(op->groupClauses, tlist, NULL);
/* punt if nothing to group on (can this happen?) */
if (groupList == NIL)
@@ -678,9 +894,13 @@ static List *
recurse_union_children(Node *setOp, PlannerInfo *root,
double tuple_fraction,
SetOperationStmt *top_union,
- List *refnames_tlist)
+ List *refnames_tlist,
+ List **child_sortclauses)
{
- List *child_sortclauses;
+ List *lplan, *rplan;
+ List *lsort, *rsort;
+
+ *child_sortclauses = NIL;
if (IsA(setOp, SetOperationStmt))
{
@@ -691,14 +911,23 @@ recurse_union_children(Node *setOp, PlannerInfo *root,
equal(op->colTypes, top_union->colTypes))
{
/* Same UNION, so fold children into parent's subplan list */
- return list_concat(recurse_union_children(op->larg, root,
- tuple_fraction,
- top_union,
- refnames_tlist),
- recurse_union_children(op->rarg, root,
- tuple_fraction,
- top_union,
- refnames_tlist));
+ lplan = recurse_union_children(op->larg, root,
+ tuple_fraction,
+ top_union,
+ refnames_tlist,
+ &lsort);
+ rplan = recurse_union_children(op->rarg, root,
+ tuple_fraction,
+ top_union,
+ refnames_tlist,
+ &rsort);
+ /*
+ * Propagate whether all the descendents are sorted with same
+ * sortClause.
+ */
+ if (lsort != NIL && equal(lsort, rsort))
+ *child_sortclauses = lsort;
+ return list_concat(lplan, rplan);
}
}
@@ -715,13 +944,16 @@ recurse_union_children(Node *setOp, PlannerInfo *root,
tuple_fraction,
top_union->colTypes,
top_union->colCollations,
+ top_union->groupClauses,
false, -1,
refnames_tlist,
- &child_sortclauses, NULL));
+ child_sortclauses, NULL));
}
/*
* Add nodes to the given plan tree to unique-ify the result of a UNION.
+ *
+ * If the sortClause is given, we assume the plan is already sorted on it.
*/
static Plan *
make_union_unique(SetOperationStmt *op, Plan *plan,
@@ -731,9 +963,11 @@ make_union_unique(SetOperationStmt *op, Plan *plan,
List *groupList;
double dNumGroups;
long numGroups;
+ bool sort_needed = true;
/* Identify the grouping semantics */
- groupList = generate_setop_grouplist(op, plan->targetlist);
+ groupList = generate_setop_grouplist(op->groupClauses,
+ plan->targetlist, *sortClauses);
/* punt if nothing to group on (can this happen?) */
if (groupList == NIL)
@@ -742,6 +976,9 @@ make_union_unique(SetOperationStmt *op, Plan *plan,
return plan;
}
+ if (*sortClauses && equal(*sortClauses, groupList))
+ sort_needed = false;
+
/*
* XXX for the moment, take the number of distinct groups as equal to the
* total input size, ie, the worst case. This is too conservative, but we
@@ -756,7 +993,8 @@ make_union_unique(SetOperationStmt *op, Plan *plan,
numGroups = (long) Min(dNumGroups, (double) LONG_MAX);
/* Decide whether to hash or sort */
- if (choose_hashed_setop(root, groupList, plan,
+ if (sort_needed &&
+ choose_hashed_setop(root, groupList, plan,
dNumGroups, dNumGroups, tuple_fraction,
"UNION"))
{
@@ -778,7 +1016,9 @@ make_union_unique(SetOperationStmt *op, Plan *plan,
else
{
/* Sort and Unique */
- plan = (Plan *) make_sort_from_sortclauses(root, groupList, plan);
+ if (sort_needed)
+ plan = (Plan *) make_sort_from_sortclauses(root, groupList, plan);
+
plan = (Plan *) make_unique(plan, groupList);
plan->plan_rows = dNumGroups;
/* We know the sort order of the result */
@@ -1145,23 +1385,34 @@ generate_append_tlist(List *colTypes, List *colCollations,
* the parser output representation doesn't include a tlist for each
* setop. So what we need to do here is copy that list and install
* proper sortgrouprefs into it and into the targetlist.
+ *
+ * sortClause is consulted if provided to avoid re-sorting with different
+ * orderings on the same keys later.
*/
static List *
-generate_setop_grouplist(SetOperationStmt *op, List *targetlist)
+generate_setop_grouplist(List *groupClauses, List *targetlist,
+ List *sortClauses)
{
- List *grouplist = (List *) copyObject(op->groupClauses);
+ List *grouplist = (List *) copyObject(groupClauses);
ListCell *lg;
+ ListCell *ls = NULL;
ListCell *lt;
Index refno = 1;
lg = list_head(grouplist);
+
+ if (sortClauses)
+ ls = list_head(sortClauses);
+
foreach(lt, targetlist)
{
TargetEntry *tle = (TargetEntry *) lfirst(lt);
- SortGroupClause *sgc;
+ SortGroupClause *sgc, *sgc_sort = NULL;
- /* tlist shouldn't have any sortgrouprefs yet */
- Assert(tle->ressortgroupref == 0);
+ /*
+ * tlist shouldn't have any sortgrouprefs yet, or should be unchanged
+ */
+ Assert(tle->ressortgroupref == 0 || tle->ressortgroupref == refno);
if (tle->resjunk)
continue; /* ignore resjunk columns */
@@ -1174,6 +1425,45 @@ generate_setop_grouplist(SetOperationStmt *op, List *targetlist)
/* we could use assignSortGroupRef here, but seems a bit silly */
sgc->tleSortGroupRef = tle->ressortgroupref = refno++;
+
+ if (ls)
+ {
+ /*
+ * If sortClauses is provided, try to adjust the sorting order to
+ * get the chance for omitting sorting for grouping later.
+ */
+ sgc_sort = (SortGroupClause *) lfirst(ls);
+ ls = lnext(ls);
+ if (sgc->sortop != sgc_sort->sortop)
+ {
+ Oid reverse = InvalidOid;
+ Oid opfamily, opcintype;
+ int16 strategy;
+
+ if (get_ordering_op_properties(sgc->sortop,
+ &opfamily, &opcintype, &strategy))
+ {
+ switch (strategy)
+ {
+ case BTLessStrategyNumber:
+ strategy = BTGreaterStrategyNumber; break;
+ case BTGreaterStrategyNumber:
+ strategy = BTLessStrategyNumber; break;
+ }
+
+ reverse = get_opfamily_member(opfamily,
+ opcintype,
+ opcintype,
+ strategy);
+ if (sgc_sort->sortop == reverse)
+ {
+ sgc->sortop = reverse;
+ sgc->nulls_first = sgc_sort->nulls_first;
+ }
+ }
+ }
+ }
+
}
Assert(lg == NULL);
return grouplist;
--
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