Reduce number of "stat" syscalls for MergeTree data parts

dbms/src/Common/ErrorCodes.cpp

@@ -430,6 +430,7 @@ namespace ErrorCodes
     extern const int MYSQL_CLIENT_INSUFFICIENT_CAPABILITIES = 453;
     extern const int OPENSSL_ERROR = 454;
     extern const int SUSPICIOUS_TYPE_FOR_LOW_CARDINALITY = 455;
+    extern const int CANNOT_UNLINK = 458;
 
     extern const int KEEPER_EXCEPTION = 999;
     extern const int POCO_EXCEPTION = 1000;

dbms/src/Storages/MergeTree/MergeTreeDataPart.cpp

@@ -402,15 +402,19 @@ void MergeTreeDataPart::remove() const
 
         for (const auto & [file, _] : checksums.files)
         {
-            if (0 != unlink((to + "/" + file).c_str()))
-                throwFromErrno("Cannot unlink file", ErrorCodes::CANNOT_UNLINK);
+            String path_to_remove = to + "/" + file;
+            if (0 != unlink(path_to_remove.c_str()))
+                throwFromErrno("Cannot unlink file " + path_to_remove, ErrorCodes::CANNOT_UNLINK);
         }
 
-        if (0 != unlink((to + "/checksums.txt").c_str()))
-            throwFromErrno("Cannot unlink file", ErrorCodes::CANNOT_UNLINK);
+        {
+            String path_to_remove = to + "/checksums.txt";
+            if (0 != unlink(path_to_remove.c_str()))
+                throwFromErrno("Cannot unlink file", ErrorCodes::CANNOT_UNLINK);
+        }
 
         if (0 != rmdir(to.c_str()))
-            throwFromErrno("Cannot rmdir file", ErrorCodes::CANNOT_UNLINK);
+            throwFromErrno("Cannot rmdir file " + to, ErrorCodes::CANNOT_UNLINK);
     }
     catch (...)
     {