Backport #92860 to 25.12: Fix bad creation of sparse columns during mutation in Wide part

robot-clickhouse · robot-clickhouse · commit 4942c2dfd934 · 2025-12-23T21:14:32.000Z
diff --git a/src/Storages/MergeTree/MutateTask.cpp b/src/Storages/MergeTree/MutateTask.cpp
@@ -591,7 +591,14 @@ getColumnsForNewDataPart(
     /// settings will not be applied for them (for example, new serialization versions for data types).
     if (!affects_all_columns)
     {
-        settings = serialization_infos.getSettings();
+        settings = SerializationInfo::Settings
+        {
+            (*source_part->storage.getSettings())[MergeTreeSetting::ratio_of_defaults_for_sparse_serialization],
+            false,
+            serialization_infos.getSettings().version,
+            serialization_infos.getSettings().string_serialization_version,
+            serialization_infos.getSettings().nullable_serialization_version,
+        };
     }
     /// Otherwise use fresh settings from storage.
     else
diff --git a/tests/queries/0_stateless/03774_wide_part_mutation_sparse_ratio_setting_bug.reference b/tests/queries/0_stateless/03774_wide_part_mutation_sparse_ratio_setting_bug.reference
@@ -0,0 +1,10 @@
+0	42
+1	42
+2	42
+3	42
+4	42
+5	42
+6	42
+7	42
+8	42
+9	42
diff --git a/tests/queries/0_stateless/03774_wide_part_mutation_sparse_ratio_setting_bug.sql b/tests/queries/0_stateless/03774_wide_part_mutation_sparse_ratio_setting_bug.sql
@@ -0,0 +1,14 @@
+drop table if exists test;
+create table test (a UInt32, b UInt32) engine=MergeTree order by tuple() settings min_bytes_for_wide_part=0, ratio_of_defaults_for_sparse_serialization=0.0, max_suspicious_broken_parts=0, max_suspicious_broken_parts_bytes=0;
+insert into test select number, number from numbers(10);
+
+detach table test;
+attach table test;
+
+alter table test update b = 42 where 1 settings mutations_sync=2;
+
+detach table test;
+attach table test;
+
+select * from test;
+drop table test;

-Original file line number
+Diff line change
@@ @@ -0,0 +1,10 @@ @@
 +0	42
 +1	42
 +2	42
 +3	42
 +4	42
 +5	42
 +6	42
 +7	42
 +8	42
 +9	42