presto-hive/src/main/java/io/prestosql/plugin/hive/metastore/file/FileHiveMetastore.java/FileHiveMetastore/getChildSchemaDirectories
class FileHiveMetastore:    private List<Path> getChildSchemaDirectories(Path metadataDirectory)
    {
        try {
            if (!metadataFileSystem.isDirectory(metadataDirectory)) {
                return ImmutableList.of();
            }

            ImmutableList.Builder<Path> childSchemaDirectories = ImmutableList.builder();
            for (FileStatus child : metadataFileSystem.listStatus(metadataDirectory)) {
                if (!child.isDirectory()) {
                    continue;
                }
                Path childPath = child.getPath();
                if (childPath.getName().startsWith(".")) {
                    continue;
                }
                if (metadataFileSystem.isFile(new Path(childPath, PRESTO_SCHEMA_FILE_NAME))) {
                    childSchemaDirectories.add(childPath);
                }
            }
            return childSchemaDirectories.build();
        }
        catch (IOException e) {
            throw new PrestoException(HIVE_METASTORE_ERROR, e);
        }
    }