optimize limit 0 query by skipping ranges call (#17535)

matrixorigin · Jul 15, 2024 · b44e732 · b44e732
1 parent b410d7b
commit b44e732
Showing 1 changed file with 14 additions and 1 deletion.
diff --git a/pkg/sql/compile/compile.go b/pkg/sql/compile/compile.go
@@ -1245,6  1245,20 @@ func (c *Compile) compilePlanScope(step int32, curNodeIdx int32, ns []*plan.Node
 		ss = c.compileSort(n, c.compileProjection(n, c.compileRestrict(node, ss)))
 		return ss, nil
 	case plan.Node_TABLE_SCAN:
 		if n.Limit != nil {
 			if cExpr, ok := n.Limit.Expr.(*plan.Expr_Lit); ok {
 				if cval, ok := cExpr.Lit.Value.(*plan.Literal_U64Val); ok {
 					if cval.U64Val == 0 {
 						// optimize for limit 0
 						rs := newScope(Merge)
 						rs.NodeInfo = engine.Node{Addr: c.addr, Mcpu: 1}
 						rs.Proc = process.NewFromProc(c.proc, c.proc.Ctx, 0)
 						return c.compileLimit(n, []*Scope{rs}), nil
 					}
 				}
 			}
 		}
 
 		c.appendMetaTables(n.ObjRef)
 		ss, err = c.compileTableScan(n)
 		if err != nil {
@@ -2968,7  2982,6 @@ func (c *Compile) compileOffset(n *plan.Node, ss []*Scope) []*Scope {
 
 func (c *Compile) compileLimit(n *plan.Node, ss []*Scope) []*Scope {
 	currentFirstFlag := c.anal.isFirst
-
 	for i := range ss {
 		c.anal.isFirst = currentFirstFlag
 		if containBrokenNode(ss[i]) {