// locate subqueries or SRF in given expr and create plan for each
// subquery, no change on the expr itself.
//
LogicNode setReturningExprCreatePlan(LogicNode root, Expr expr)
{
var newroot = root;
var subplans = new List <NamedQuery>();
expr.VisitEachT <Expr>(e =>
{
if (e is SubqueryExpr x)
{
Debug.Assert(expr.HasSubQuery());
x.query_.CreatePlan();
subplans.Add(new NamedQuery(x.query_, null));
// functionally we don't have to do rewrite since above
// plan is already runnable
if (queryOpt_.optimize_.enable_subquery_unnest_)
{
// use the plan 'root' containing the subexpr 'x'
var replacement = oneSubqueryToJoin(root, x);
newroot = (LogicNode)newroot.SearchAndReplace(root,
replacement);
}
}
else if (e is FuncExpr f && f.isSRF_)
{
var newchild = new LogicProjectSet(root.child_());
root.children_[0] = newchild;
}
});
subQueries_.AddRange(subplans);
return(newroot);
}
// locate subqueries or SRF in given expr and create plan for each
// subquery, no change on the expr itself.
//
LogicNode setReturningExprCreatePlan(LogicNode root, Expr expr)
{
var newroot = root;
var subplans = new List <NamedQuery>();
expr.VisitEachT <Expr>(e =>
{
if (e is SubqueryExpr x)
{
Debug.Assert(expr.HasSubQuery());
x.query_.cteInfo_ = this.cteInfo_;
x.query_.CreatePlan();
subplans.Add(new NamedQuery(x.query_, null, NamedQuery.QueryType.UNSURE));
// functionally we don't have to do rewrite since above
// plan is already runnable
if (queryOpt_.optimize_.enable_subquery_unnest_)
{
// use the plan 'root' containing the subexpr 'x'
bool canReplaceRoot = false;
var replacement = oneSubqueryToJoin(root, x, ref canReplaceRoot);
newroot = (LogicNode)newroot.SearchAndReplace(root,
replacement);
// consider mark@1 or @2 , @2 is not unnested yet,
// so it can't be push down i.e. it keep as a root
if (canReplaceRoot)
{
root = newroot;
}
}
}
else if (e is FuncExpr f && f.isSRF_)
{
var newchild = new LogicProjectSet(root.child_());
root.children_[0] = newchild;
}
});
subQueries_.AddRange(subplans);
return(newroot);
}
// expands [NOT] EXISTS filter to mark join
//
// LogicNode_A
// Filter: @1 AND|OR <others1>
// <ExistSubqueryExpr> 1
// -> LogicNode_B
// Filter: b.b1[0]=?a.a1[0] AND|OR <others2>
// =>
// Filter
// Filter: #marker AND|OR <others1>
// MarkJoin
// Filter: (b.b1[0]=a.a1[0]) AND|OR <others2> as #marker
// LogicNode_A
// LogicNode_B
//
// further convert DJoin to semi-join here is by decorrelate process
//
LogicNode existsToMarkJoin(LogicNode nodeA, ExistSubqueryExpr existExpr)
{
var nodeAIsOnMarkJoin =
nodeA is LogicFilter && (nodeA.child_() is LogicMarkJoin || nodeA.child_() is LogicSingleJoin);
// nodeB contains the join filter
var nodeB = existExpr.query_.logicPlan_;
var nodeBFilter = nodeB.filter_;
nodeB.NullifyFilter();
// nullify nodeA's filter: the rest is push to top filter. However,
// if nodeA is a Filter|MarkJoin, keep its mark filter.
var markerFilter = new ExprRef(new MarkerExpr(), 0);
var nodeAFilter = nodeA.filter_;
if (nodeAIsOnMarkJoin)
{
nodeA.filter_ = markerFilter;
}
else
{
if (nodeAFilter != null)
{
// a1 > @1 and a2 > @2 and a3 > 2, scalarExpr = @1
// keeplist: a1 > @1 and a3 > 2
// andlist after removal: a2 > @2
// nodeAFilter = a1 > @1 and a3 > 2
//
var andlist = nodeAFilter.FilterToAndList();
var keeplist = andlist.Where(x => x.VisitEachExists(e => e.Equals(existExpr))).ToList();
andlist.RemoveAll(x => x.VisitEachExists(e => e.Equals(existExpr)));
if (andlist.Count == 0)
{
nodeA.NullifyFilter();
}
else
{
nodeA.filter_ = andlist.AndListToExpr();
if (keeplist.Count > 0)
{
nodeAFilter = keeplist.AndListToExpr();
}
else
{
nodeAFilter = markerFilter;
}
}
}
}
// make a mark join
LogicMarkJoin markjoin;
if (existExpr.hasNot_)
{
markjoin = new LogicMarkAntiSemiJoin(nodeA, nodeB);
}
else
{
markjoin = new LogicMarkSemiJoin(nodeA, nodeB);
}
// make a filter on top of the mark join collecting all filters
Expr topfilter;
if (nodeAIsOnMarkJoin)
{
topfilter = nodeAFilter.SearchReplace(existExpr, LiteralExpr.MakeLiteral("true", new BoolType()));
}
else
{
topfilter = nodeAFilter.SearchReplace(existExpr, markerFilter);
}
nodeBFilter.DeParameter(nodeA.InclusiveTableRefs());
topfilter = topfilter.AddAndFilter(nodeBFilter);
LogicFilter Filter = new LogicFilter(markjoin, topfilter);
return(Filter);
}
