document and fix style

Author: jkartseva

src/Disks/IDisk.h

@@ -442,6 +442,7 @@ class IDisk : public Space
 
     virtual bool isReadOnly() const { return false; }
 
+    /// If the disk is plain object storage.
     virtual bool isPlain() const { return false; }
 
     virtual bool isWriteOnce() const { return false; }

src/Disks/IStoragePolicy.h

@@ -59,7 +59,7 @@ class IStoragePolicy
     VolumePtr getVolumeByName(const String & volume_name) const;
     /// Checks if storage policy can be replaced by another one.
     virtual void checkCompatibleWith(const StoragePolicyPtr & new_storage_policy) const = 0;
-    ///
+    /// If the policy allows table partition operations (move, replace) with the other storage policy.
     virtual bool isCompatibleForPartitionOps(const StoragePolicyPtr & other) const = 0;
     /// Finds a volume index, which contains disk
     virtual std::optional<size_t> tryGetVolumeIndexByDiskName(const String & disk_name) const = 0;

src/Disks/StoragePolicy.h

@@ -82,7 +82,7 @@ class StoragePolicy : public IStoragePolicy
     /// Checks if storage policy can be replaced by another one.
     void checkCompatibleWith(const StoragePolicyPtr & new_storage_policy) const override;
 
-    ///
+    /// If the policy allows table partition operations (move, replace) with the other storage policy.
     bool isCompatibleForPartitionOps(const StoragePolicyPtr & other) const override;
 
     /// Check if we have any volume with stopped merges

src/Storages/StorageMergeTree.cpp

@@ -2268,7 +2268,7 @@ void StorageMergeTree::replacePartitionFrom(const StoragePtr & source_table, con
 
     static const String TMP_PREFIX = "tmp_replace_from_";
 
-    bool are_policies_partition_compatible = getStoragePolicy()->isCompatibleForPartitionOps(source_table->getStoragePolicy());
+    bool are_policies_partition_op_compatible = getStoragePolicy()->isCompatibleForPartitionOps(source_table->getStoragePolicy());
     for (const DataPartPtr & src_part : src_parts)
     {
         if (is_all)
@@ -2295,7 +2295,7 @@ void StorageMergeTree::replacePartitionFrom(const StoragePtr & source_table, con
                 clone_params,
                 local_context->getReadSettings(),
                 local_context->getWriteSettings(),
-                !are_policies_partition_compatible /*must_on_same_disk*/);
+                !are_policies_partition_op_compatible /*must_on_same_disk*/);
             dst_parts.emplace_back(std::move(dst_part));
             dst_parts_locks.emplace_back(std::move(part_lock));
         }
@@ -2372,12 +2372,13 @@ void StorageMergeTree::movePartitionToTable(const StoragePtr & dest_table, const
         throw Exception(ErrorCodes::NOT_IMPLEMENTED,
                         "Table {} supports movePartitionToTable only for MergeTree family of table engines. Got {}",
                         getStorageID().getNameForLogs(), dest_table->getName());
-    bool are_policies_partition_compatible = getStoragePolicy()->isCompatibleForPartitionOps(dest_table_storage->getStoragePolicy());
+    bool are_policies_partition_op_compatible = getStoragePolicy()->isCompatibleForPartitionOps(dest_table_storage->getStoragePolicy());
 
-    if (!are_policies_partition_compatible)
+    if (!are_policies_partition_op_compatible)
         throw Exception(
             ErrorCodes::UNKNOWN_POLICY,
-            "Destination table {} should have the same or partition compatible storage policy of source table {}. {}: {}, {}: {}",
+            "Destination table {} should have the same storage policy of source table, or the policies must be compatible for partition "
+            "operations {}. {}: {}, {}: {}",
             dest_table_storage->getStorageID().getNameForLogs(),
             getStorageID().getNameForLogs(),
             getStorageID().getNameForLogs(),
@@ -2443,7 +2444,7 @@ void StorageMergeTree::movePartitionToTable(const StoragePtr & dest_table, const
             clone_params,
             local_context->getReadSettings(),
             local_context->getWriteSettings(),
-            !are_policies_partition_compatible /*must_on_same_disk*/
+            !are_policies_partition_op_compatible /*must_on_same_disk*/
         );
 
         dst_parts.emplace_back(std::move(dst_part));