public Path getLocalDataRoot() {
        if (localDataRoot == null) {
            String localDataRootDirStr = mustGetProperty(LOCAL_DATA_ROOT);
            localDataRoot = Paths.get(localDataRootDirStr);
            if (!Files.exists(localDataRoot)) {
                try {
                    Files.createDirectories(localDataRoot);
                } catch (IOException e) {
                    throw new RuntimeException(e);
                }
            }
        }
        return localDataRoot;
    }
The path where realtime segments declare.
<pre>
    .../rt/table/tableA/host0/seg0_0 ... segN_0
    .../rt/table/tableA/host1/seg0_1 ... segN_1
</pre>
indexr-server/src/main/java/io/indexr/server/IndexRConfig.java