add test

src/Processors/Merges/Algorithms/MergeTreeReadInfo.h

@@ -29,7 +29,7 @@ inline bool getVirtualRowFromChunk(const Chunk & chunk)
     const auto & info = chunk.getChunkInfo();
     if (const auto * read_info = typeid_cast<const MergeTreeReadInfo *>(info.get()))
         return read_info->virtual_row;
-    return 0;
+    return false;
 }
 
 }

tests/queries/0_stateless/03031_read_in_order_optimization.reference

@@ -0,0 +1,5 @@
+0
+1
+2
+3
+24578

tests/queries/0_stateless/03031_read_in_order_optimization.sql

@@ -0,0 +1,48 @@
+
+DROP TABLE IF EXISTS t;
+
+CREATE TABLE t
+(
+    `x` UInt64,
+    `y` UInt64,
+    `z` UInt64,
+    `k` UInt64
+)
+ENGINE = MergeTree
+ORDER BY (x, y, z)
+SETTINGS index_granularity = 8192;
+
+INSERT INTO t SELECT
+    number,
+    number,
+    number,
+    number
+FROM numbers(8192 * 3);
+
+INSERT INTO t SELECT
+    number + (8192 * 3),
+    number + (8192 * 3),
+    number + (8192 * 3),
+    number + (8192 * 3)
+FROM numbers(8192 * 3);
+
+SELECT x
+FROM t
+ORDER BY x ASC
+LIMIT 4
+SETTINGS max_block_size = 8192,
+read_in_order_two_level_merge_threshold = 0,
+max_threads = 1,
+optimize_read_in_order = 1;
+
+SYSTEM FLUSH LOGS;
+
+SELECT read_rows
+FROM system.query_log
+WHERE current_database = currentDatabase()
+AND query like '%SELECT x%'
+AND query not like '%system.query_log%'
+ORDER BY query_start_time DESC, read_rows DESC
+LIMIT 1;
+
+DROP TABLE t;