Backport #94725 to 25.12: Preserve constant index granularity (use_const_adaptive_granularity) after Vertical merges

robot-clickhouse · robot-clickhouse · commit eba7edd237c7 · 2026-01-22T08:18:26.000Z
diff --git a/src/Storages/MergeTree/MergeTask.cpp b/src/Storages/MergeTree/MergeTask.cpp
@@ -2432,8 +2432,6 @@ void MergeTask::ExecuteAndFinalizeHorizontalPart::createMergedStream() const
         }
 
         const bool is_vertical_merge = (global_ctx->chosen_merge_algorithm == MergeAlgorithm::Vertical);
-        /// If merge is vertical we cannot calculate it
-        ctx->blocks_are_granules_size = is_vertical_merge;
 
         if (global_ctx->cleanup && !(*merge_tree_settings)[MergeTreeSetting::allow_experimental_replacing_merge_with_cleanup])
             throw Exception(ErrorCodes::SUPPORT_IS_DISABLED, "Experimental merges with CLEANUP are not allowed");
@@ -2455,7 +2453,7 @@ void MergeTask::ExecuteAndFinalizeHorizontalPart::createMergedStream() const
             (*merge_tree_settings)[MergeTreeSetting::merge_max_block_size],
             (*merge_tree_settings)[MergeTreeSetting::merge_max_block_size_bytes],
             max_dynamic_subcolumns,
-            ctx->blocks_are_granules_size,
+            is_vertical_merge,
             cleanup,
             global_ctx->time_of_merge);
 
diff --git a/tests/queries/0_stateless/03800_use_const_adaptive_granularity_vertical_merge.reference b/tests/queries/0_stateless/03800_use_const_adaptive_granularity_vertical_merge.reference
@@ -0,0 +1,11 @@
+-- { echo }
+insert into tab select 1, if(number < 4096, 'foo', repeat('b', 1000)) from numbers(400e3) settings max_block_size=65535, max_insert_threads=1;
+select name, rows, marks, index_granularity_bytes_in_memory_allocated from system.parts where database = currentDatabase() and table = 'tab' and active;
+1_1_1_0	327675	3278	25
+1_2_2_0	72325	740	25
+optimize table tab;
+select name, rows, marks, index_granularity_bytes_in_memory_allocated from system.parts where database = currentDatabase() and table = 'tab' and active;
+1_1_2_1	400000	4001	25
+select * from tab format Null;
+check table tab;
+1_1_2_1	1	
diff --git a/tests/queries/0_stateless/03800_use_const_adaptive_granularity_vertical_merge.sql b/tests/queries/0_stateless/03800_use_const_adaptive_granularity_vertical_merge.sql
@@ -0,0 +1,31 @@
+DROP TABLE IF EXISTS tab;
+
+CREATE TABLE tab
+(
+    part Int32,
+    key String
+)
+ENGINE = MergeTree
+PARTITION BY part
+ORDER BY key
+SETTINGS
+    index_granularity = 1000000000,
+    index_granularity_bytes = 100000,
+    min_bytes_for_wide_part = 0,
+    use_const_adaptive_granularity = 1,
+    enable_index_granularity_compression = 1,
+    enable_block_number_column = 0,
+    enable_block_offset_column = 0,
+    auto_statistics_types = '',
+    vertical_merge_algorithm_min_rows_to_activate = 0,
+    vertical_merge_algorithm_min_columns_to_activate = 1,
+    string_serialization_version = 'single_stream',
+    merge_max_block_size = 65535;
+
+-- { echo }
+insert into tab select 1, if(number < 4096, 'foo', repeat('b', 1000)) from numbers(400e3) settings max_block_size=65535, max_insert_threads=1;
+select name, rows, marks, index_granularity_bytes_in_memory_allocated from system.parts where database = currentDatabase() and table = 'tab' and active;
+optimize table tab;
+select name, rows, marks, index_granularity_bytes_in_memory_allocated from system.parts where database = currentDatabase() and table = 'tab' and active;
+select * from tab format Null;
+check table tab;
