91.58% (185/202)

Uncovered changed code (with context):

================================================================================
src/Processors/Merges/IMergingTransform.cpp
================================================================================

--- uncovered block 220-220 ---
      218 |             const auto & input_chunk = state.input_chunk.chunk;
      219 |             if (!input_chunk.hasRows() && !isVirtualRow(input_chunk) && !input.isFinished())
>>    220 |                 return Status::NeedData;
      221 | 
      222 |             state.has_input = true;
================================================================================
src/Processors/QueryPlan/BufferChunksTransform.cpp
================================================================================

--- uncovered block 48-52 ---
       46 | 
       47 |             if (isVirtualRow(chunk))
>>     48 |             {
>>     49 |                 output.push(std::move(chunk));
>>     50 |                 input.setNotNeeded();
>>     51 |                 return Status::PortFull;
>>     52 |             }
       53 | 
       54 |             num_buffered_rows -= chunk.getNumRows();

--- uncovered block 77-81 ---
       75 |         auto chunk = pullChunk(virtual_row);
       76 |         if (virtual_row)
>>     77 |         {
>>     78 |             chunks.push(std::move(chunk));
>>     79 |             input.setNotNeeded();
>>     80 |             return Status::PortFull;
>>     81 |         }
       82 |         num_buffered_rows += chunk.getNumRows();
       83 |         num_buffered_bytes += chunk.bytes();
================================================================================
src/Processors/QueryPlan/SortingStep.cpp
================================================================================

--- uncovered block 524-526 ---
      522 |     }
      523 |     else if (apply_virtual_row_conversions)
>>    524 |     {
>>    525 |         pipeline.addSimpleTransform(RemoveVirtualRowTransform::create);
>>    526 |     }
      527 | }
      528 | 
================================================================================
src/Storages/MergeTree/MergeTreeSelectProcessor.cpp
================================================================================

--- uncovered block 285-285 ---
      283 | {
      284 |     if (!virtual_row_conversions || read_mark_ranges.empty())
>>    285 |         return {};
      286 | 
      287 |     const auto & data_part = current_task.getInfo().data_part;

--- uncovered block 300-300 ---
      298 |     size_t num_pk_columns = pk_block_header.columns();
      299 |     if (index->size() < num_pk_columns)
>>    300 |         return {};
      301 | 
      302 |     bool has_value = std::ranges::all_of(*index, [&](const auto & col) { return col->size() > next_mark; });

--- uncovered block 304-304 ---
      302 |     bool has_value = std::ranges::all_of(*index, [&](const auto & col) { return col->size() > next_mark; });
      303 |     if (!has_value)
>>    304 |         return {};
      305 | 
      306 |     ColumnsWithTypeAndName pk_columns;

=== Lost Baseline Coverage: 7 lines ===

================================================================================
src/Processors/Merges/IMergingTransform.cpp
================================================================================

--- lost coverage block 123-126 ---
      121 |         {
      122 |             if (!input.isFinished())
>>    123 |             {
>>    124 |                 input.setNeeded();
>>    125 |                 all_inputs_has_data = false;
>>    126 |             }
      127 | 
      128 |             continue;
================================================================================
src/Processors/QueryPlan/SortingStep.cpp
================================================================================

--- lost coverage block 382-382 ---
      380 |     if (pipeline.getNumStreams() > 1)
      381 |     {
>>    382 |         /// Disable buffering when `read_in_order_use_virtual_row_per_block` is enabled, these optimizations are incompatible.
      383 |         /// Buffering would need to flush virtual rows, otherwise virtual rows lose their purpose while reading from the stream.
      384 |         /// But flushing a virtual row between every block effectively turns buffering into a no-op.
================================================================================
src/Storages/MergeTree/MergeTreeSelectProcessor.cpp
================================================================================

--- lost coverage block 269-269 ---
      267 |     if (reader_settings.use_query_condition_cache && prewhere_info)
      268 |         current_task.addPrewhereUnmatchedMarks(res.read_mark_ranges);
>>    269 | 
      270 |     return {Chunk(), res.num_read_rows, res.num_read_bytes, false, std::move(res.read_mark_ranges)};
      271 | }

--- lost coverage block 390-390 ---
      388 | 
      389 |         /// Emit a virtual row update after each block, carrying the next mark's PK boundary.
>>    390 |         /// This allows MergingSortedTransform to reprioritize sources when:
      391 |         /// - PREWHERE filters all rows (merge gets updated position without actual data)
      392 |         /// - A downstream filter (WHERE, JOIN) removes all rows (virtual row passes through filters)
WARNING: Failed to get start time for [Print Uncovered Code] - start time and duration won't be set

--- Coverage counts ---
Lines     : baseline 742,429/883,512  →  current 742,687/883,611  (Δ +258 / +99)
Functions : baseline 798,976/879,291  →  current 799,151/879,426  (Δ +175 / +135)
Branches  : baseline 240,940/314,792  →  current 241,087/314,850  (Δ +147 / +58)