diff --git a/server/conn.go b/server/conn.go
index 8d13186872a6b..220aeb1ef3148 100644
--- a/server/conn.go
+++ b/server/conn.go
@@ -2048,9 +2048,9 @@ func (cc *clientConn) prefetchPointPlanKeys(ctx context.Context, stmts []ast.Stm
 			return nil, nil
 		}
 		// TODO: the preprocess is run twice, we should find some way to avoid do it again.
-		// TODO: handle the PreprocessorReturn.
 		if err = plannercore.Preprocess(ctx, cc.getCtx(), stmt); err != nil {
-			return nil, err
+			// error might happen, see https://github.com/pingcap/tidb/issues/39664
+			return nil, nil
 		}
 		p := plannercore.TryFastPlan(cc.ctx.Session, stmt)
 		pointPlans[i] = p