Little better [#CLICKHOUSE-3231].

dbms/src/Storages/MergeTree/DataPartsExchange.cpp

@@ -268,9 +268,7 @@ MergeTreeData::MutableDataPartPtr Fetcher::fetchPartImpl(
     new_data_part->info = MergeTreePartInfo::fromPartName(part_name);
     MergeTreePartInfo::parseMinMaxDatesFromPartName(part_name, new_data_part->min_date, new_data_part->max_date);
     new_data_part->modification_time = time(nullptr);
-    new_data_part->loadColumns(true);
+    new_data_part->loadColumnsChecksumsIndex(true, false);
-    new_data_part->loadChecksums(true);
-    new_data_part->loadIndex();
     new_data_part->is_sharded = false;
     new_data_part->checksums.checkEqual(checksums, false);
 

dbms/src/Storages/MergeTree/MergeTreeData.cpp

@@ -302,7 +302,7 @@ void MergeTreeData::loadDataParts(bool skip_sanity_checks)
     Poco::DirectoryIterator end;
     for (Poco::DirectoryIterator it(full_path); it != end; ++it)
     {
-        /// Skip temporary directories older than one day.
+        /// Skip temporary directories.
         if (startsWith(it.name(), "tmp"))
             continue;
 
@@ -326,10 +326,7 @@ void MergeTreeData::loadDataParts(bool skip_sanity_checks)
 
         try
         {
-            part->loadColumns(require_part_metadata);
+            part->loadColumnsChecksumsIndex(require_part_metadata, true);
-            part->loadChecksums(require_part_metadata);
-            part->loadIndex();
-            part->checkNotBroken(require_part_metadata);
         }
         catch (const Exception & e)
         {
@@ -1544,11 +1541,7 @@ MergeTreeData::MutableDataPartPtr MergeTreeData::loadPartAndFixMetadata(const St
     if (Poco::File(full_part_path + "columns.txt").exists())
         Poco::File(full_part_path + "columns.txt").remove();
 
-    part->loadColumns(false);
+    part->loadColumnsChecksumsIndex(false, true);
-    part->loadChecksums(false);
-    part->loadIndex();
-    part->checkNotBroken(false);
-
     part->modification_time = Poco::File(full_part_path).getLastModified().epochTime();
 
     /// If the checksums file is not present, calculate the checksums and write them to disk.

dbms/src/Storages/MergeTree/MergeTreeDataPart.cpp

@@ -529,6 +529,17 @@ void MergeTreeDataPart::renameAddPrefix(bool to_detached, const String & prefix)
     renameTo(dst_name());
 }
 
+
+void MergeTreeDataPart::loadColumnsChecksumsIndex(bool require_columns_checksums, bool check_consistency)
+{
+    loadColumns(require_columns_checksums);
+    loadChecksums(require_columns_checksums);
+    loadIndex();
+    if (check_consistency)
+        checkConsistency(require_columns_checksums);
+}
+
+
 void MergeTreeDataPart::loadIndex()
 {
     /// Size - in number of marks.
@@ -627,7 +638,7 @@ void MergeTreeDataPart::loadColumns(bool require)
     columns.readText(file);
 }
 
-void MergeTreeDataPart::checkNotBroken(bool require_part_metadata)
+void MergeTreeDataPart::checkConsistency(bool require_part_metadata)
 {
     String path = getFullPath();
 

dbms/src/Storages/MergeTree/MergeTreeDataPart.h

@@ -180,19 +180,12 @@ struct MergeTreeDataPart
     /// Renames a part by appending a prefix to the name. To_detached - also moved to the detached directory.
     void renameAddPrefix(bool to_detached, const String & prefix) const;
 
-    /// Loads index file. Also calculates this->size if size=0
-    void loadIndex();
-
-    /// If checksums.txt exists, reads files' checksums (and sizes) from it
-    void loadChecksums(bool require);
-
     /// Populates columns_to_size map (compressed size).
     void accumulateColumnSizes(ColumnToSize & column_to_size) const;
 
-    /// Reads columns names and types from columns.txt
+    /// Initialize columns (from columns.txt if exists, or create from column files if not).
-    void loadColumns(bool require);
+    /// Load checksums from checksums.txt if exists. Load index if required.
-
+    void loadColumnsChecksumsIndex(bool require_columns_checksums, bool check_consistency);
-    void checkNotBroken(bool require_part_metadata);
 
     /// Checks that .bin and .mrk files exist
     bool hasColumnFiles(const String & column) const;
@@ -200,6 +193,18 @@ struct MergeTreeDataPart
     /// For data in RAM ('index')
     size_t getIndexSizeInBytes() const;
     size_t getIndexSizeInAllocatedBytes() const;
+
+private:
+    /// Reads columns names and types from columns.txt
+    void loadColumns(bool require);
+
+    /// If checksums.txt exists, reads files' checksums (and sizes) from it
+    void loadChecksums(bool require);
+
+    /// Loads index file. Also calculates this->size if size=0
+    void loadIndex();
+
+    void checkConsistency(bool require_part_metadata);
 };
 
 }

dbms/src/Storages/MergeTree/ShardedPartitionUploader.cpp

@@ -107,9 +107,7 @@ void Service::processQuery(const Poco::Net::HTMLForm & params, ReadBuffer & body
     data_part->info = MergeTreePartInfo::fromPartName(part_name);
     MergeTreePartInfo::parseMinMaxDatesFromPartName(part_name, data_part->min_date, data_part->max_date);
     data_part->modification_time = time(nullptr);
-    data_part->loadColumns(true);
+    data_part->loadColumnsChecksumsIndex(true, false);
-    data_part->loadChecksums(true);
-    data_part->loadIndex();
     data_part->is_sharded = false;
     data_part->checksums.checkEqual(checksums, false);