Performance of ORDER BY on sorting key prefix with braces is 2x slower than without due to inefficient execution plan.
Without braces:
```sql
EXPLAIN PIPELINE
SELECT
    CounterID,
    EventDate
FROM hits_v1
ORDER BY
    CounterID ASC,
    EventDate ASC

┌─explain───────────────────────────┐
│ (Expression)                      │
│ ExpressionTransform               │
│   (Sorting)                       │
│   MergingSortedTransform 19 → 1   │
│     (Expression)                  │
│     ExpressionTransform × 19      │
│       (ReadFromMergeTree)         │
│       MergeTreeInOrder × 19 0 → 1 │
└───────────────────────────────────┘
```
With braces:
```sql
EXPLAIN PIPELINE
SELECT
    CounterID,
    EventDate
FROM hits_v1
ORDER BY (CounterID, EventDate) ASC

┌─explain────────────────────────────────┐
│ (Expression)                           │
│ ExpressionTransform                    │
│   (Sorting)                            │
│   MergingSortedTransform 16 → 1        │
│     MergeSortingTransform × 16         │
│       LimitsCheckingTransform × 16     │
│         PartialSortingTransform × 16   │
│           (Expression)                 │
│           ExpressionTransform × 16     │
│             (ReadFromMergeTree)        │
│             MergeTreeThread × 16 0 → 1 │
└────────────────────────────────────────┘
```
{
    auto & query = getSelectQuery();
    SortDescription output_order_descr = getSortDescription(query, context);
    UInt64 limit = getLimitForSorting(query, context);
    if (input_sorting_info)
    {
        /* Case of sorting with optimization using sorting key.
         * We have several threads, each of them reads batch of parts in direct
         *  or reverse order of sorting key using one input stream per part
         *  and then merge them into one sorted stream.
         * At this stage we merge per-thread streams into one.
         */
        executeOrderOptimized(query_plan, input_sorting_info, limit, output_order_descr);
        return;
    }
    const Settings & settings = context->getSettingsRef();
    
    auto sorting_step = std::make_unique<SortingStep>(
        query_plan.getCurrentDataStream(),
        output_order_descr,
        settings.max_block_size,
        limit,