Merge pull request ClickHouse#49660 from CurtizJ/fix-sparse-columns-r…

…eload

Fix reading from sparse columns after restart

src/DataTypes/Serializations/SerializationInfo.cpp

@@ -246,7 +246,8 @@ void SerializationInfoByName::writeJSON(WriteBuffer & out) const
     return writeString(oss.str(), out);
 }
 
-void SerializationInfoByName::readJSON(ReadBuffer & in)
+SerializationInfoByName SerializationInfoByName::readJSON(
+    const NamesAndTypesList & columns, const Settings & settings, ReadBuffer & in)
 {
     String json_str;
     readString(json_str, in);
@@ -262,22 +263,36 @@ void SerializationInfoByName::readJSON(ReadBuffer & in)
             "Unknown version of serialization infos ({}). Should be less or equal than {}",
             object->getValue<size_t>(KEY_VERSION), SERIALIZATION_INFO_VERSION);
 
+    SerializationInfoByName infos;
     if (object->has(KEY_COLUMNS))
     {
+        std::unordered_map<std::string_view, const IDataType *> column_type_by_name;
+        for (const auto & [name, type] : columns)
+            column_type_by_name.emplace(name, type.get());
+
         auto array = object->getArray(KEY_COLUMNS);
         for (const auto & elem : *array)
         {
             auto elem_object = elem.extract<Poco::JSON::Object::Ptr>();
 
             if (!elem_object->has(KEY_NAME))
                 throw Exception(ErrorCodes::CORRUPTED_DATA,
-                    "Missed field '{}' in SerializationInfo of columns", KEY_NAME);
+                    "Missed field '{}' in serialization infos", KEY_NAME);
 
             auto name = elem_object->getValue<String>(KEY_NAME);
-            if (auto it = find(name); it != end())
-                it->second->fromJSON(*elem_object);
+            auto it = column_type_by_name.find(name);
+
+            if (it == column_type_by_name.end())
+                throw Exception(ErrorCodes::CORRUPTED_DATA,
+                    "Found unexpected column '{}' in serialization infos", name);
+
+            auto info = it->second->createSerializationInfo(settings);
+            info->fromJSON(*elem_object);
+            infos.emplace(name, std::move(info));
         }
     }
+
+    return infos;
 }
 
 }

src/DataTypes/Serializations/SerializationInfo.h

@@ -96,8 +96,10 @@ using MutableSerializationInfos = std::vector<MutableSerializationInfoPtr>;
 class SerializationInfoByName : public std::map<String, MutableSerializationInfoPtr>
 {
 public:
+    using Settings = SerializationInfo::Settings;
+
     SerializationInfoByName() = default;
-    SerializationInfoByName(const NamesAndTypesList & columns, const SerializationInfo::Settings & settings);
+    SerializationInfoByName(const NamesAndTypesList & columns, const Settings & settings);
 
     void add(const Block & block);
     void add(const SerializationInfoByName & other);
@@ -108,7 +110,9 @@ class SerializationInfoByName : public std::map<String, MutableSerializationInfo
     void replaceData(const SerializationInfoByName & other);
 
     void writeJSON(WriteBuffer & out) const;
-    void readJSON(ReadBuffer & in);
+
+    static SerializationInfoByName readJSON(
+        const NamesAndTypesList & columns, const Settings & settings, ReadBuffer & in);
 };
 
 }

src/Storages/MergeTree/IMergeTreeDataPart.cpp

@@ -1333,12 +1333,11 @@ void IMergeTreeDataPart::loadColumns(bool require)
         .choose_kind = false,
     };
 
-    SerializationInfoByName infos(loaded_columns, settings);
-    exists =  metadata_manager->exists(SERIALIZATION_FILE_NAME);
-    if (exists)
+    SerializationInfoByName infos;
+    if (metadata_manager->exists(SERIALIZATION_FILE_NAME))
     {
         auto in = metadata_manager->read(SERIALIZATION_FILE_NAME);
-        infos.readJSON(*in);
+        infos = SerializationInfoByName::readJSON(loaded_columns, settings, *in);
     }
 
     setColumns(loaded_columns, infos);

src/Storages/MergeTree/MergeTask.cpp

@@ -326,6 +326,7 @@ bool MergeTask::ExecuteAndFinalizeHorizontalPart::prepare()
     if (!ctx->need_remove_expired_values)
     {
         size_t expired_columns = 0;
+        auto part_serialization_infos = global_ctx->new_data_part->getSerializationInfos();
 
         for (auto & [column_name, ttl] : global_ctx->new_data_part->ttl_infos.columns_ttl)
         {
@@ -335,6 +336,8 @@ bool MergeTask::ExecuteAndFinalizeHorizontalPart::prepare()
                 LOG_TRACE(ctx->log, "Adding expired column {} for part {}", column_name, global_ctx->new_data_part->name);
                 std::erase(global_ctx->gathering_column_names, column_name);
                 std::erase(global_ctx->merging_column_names, column_name);
+                std::erase(global_ctx->all_column_names, column_name);
+                part_serialization_infos.erase(column_name);
                 ++expired_columns;
             }
         }
@@ -343,6 +346,11 @@ bool MergeTask::ExecuteAndFinalizeHorizontalPart::prepare()
         {
             global_ctx->gathering_columns = global_ctx->gathering_columns.filter(global_ctx->gathering_column_names);
             global_ctx->merging_columns = global_ctx->merging_columns.filter(global_ctx->merging_column_names);
+            global_ctx->storage_columns = global_ctx->storage_columns.filter(global_ctx->all_column_names);
+
+            global_ctx->new_data_part->setColumns(
+                global_ctx->storage_columns,
+                part_serialization_infos);
         }
     }
 

src/Storages/MergeTree/checkDataPart.cpp

@@ -94,12 +94,13 @@ IMergeTreeDataPart::Checksums checkDataPart(
     };
 
     auto ratio_of_defaults = data_part->storage.getSettings()->ratio_of_defaults_for_sparse_serialization;
-    SerializationInfoByName serialization_infos(columns_txt, SerializationInfo::Settings{ratio_of_defaults, false});
+    SerializationInfoByName serialization_infos;
 
     if (data_part_storage.exists(IMergeTreeDataPart::SERIALIZATION_FILE_NAME))
     {
         auto serialization_file = data_part_storage.readFile(IMergeTreeDataPart::SERIALIZATION_FILE_NAME, {}, std::nullopt, std::nullopt);
-        serialization_infos.readJSON(*serialization_file);
+        SerializationInfo::Settings settings{ratio_of_defaults, false};
+        serialization_infos = SerializationInfoByName::readJSON(columns_txt, settings, *serialization_file);
     }
 
     auto get_serialization = [&serialization_infos](const auto & column)

tests/queries/0_stateless/02733_sparse_columns_reload.reference

@@ -0,0 +1,2 @@
+100000
+100000

tests/queries/0_stateless/02733_sparse_columns_reload.sql

@@ -0,0 +1,18 @@
+DROP TABLE IF EXISTS t_sparse_reload;
+
+CREATE TABLE t_sparse_reload (id UInt64, v UInt64)
+ENGINE = MergeTree ORDER BY id
+SETTINGS ratio_of_defaults_for_sparse_serialization = 0.95;
+
+INSERT INTO t_sparse_reload SELECT number, 0 FROM numbers(100000);
+
+SELECT count() FROM t_sparse_reload WHERE NOT ignore(*);
+
+ALTER TABLE t_sparse_reload MODIFY SETTING ratio_of_defaults_for_sparse_serialization = 1.0;
+
+DETACH TABLE t_sparse_reload;
+ATTACH TABLE t_sparse_reload;
+
+SELECT count() FROM t_sparse_reload WHERE NOT ignore(*);
+
+DROP TABLE t_sparse_reload;