Slow metadata loading with many partitions that have inconsistent HDFS path qualification

...
        if (!dirsToLoad.contains(partDir) &&
            !FileSystemUtil.isDescendantPath(partDir, tblLocation)) { <--- this condition will fail
          // This partition has a custom filesystem location. Load its file/block
          // metadata separately by adding it to the list of dirs to load.
          dirsToLoad.add(partDir);
        }
...

  private void loadMetadataAndDiskIds(List<Path> locations,
      HashMap<Path, List<HdfsPartition>> partsByPath) {
    LOG.info(String.format("Loading file and block metadata for %s partitions: %s",
        partsByPath.size(), getFullName()));
    for (Path location: locations) { loadBlockMetadata(location, partsByPath); }
    LOG.info(String.format("Loaded file and block metadata for %s partitions: %s",
        partsByPath.size(), getFullName()));
  }

...
      // Clear the state of partitions under dirPath since they are now updated based
      // on the current snapshot of files in the directory.
      for (Map.Entry<Path, List<HdfsPartition>> entry: partsByPath.entrySet()) { <--- partsByPath has an entry for every partition in the table
        Path partDir = entry.getKey();
        if (!FileSystemUtil.isDescendantPath(partDir, dirPath)) continue;
        for (HdfsPartition partition: entry.getValue()) {
          partition.setFileDescriptors(new ArrayList<FileDescriptor>());
        }
      }
...