public PackMemCache getPackMemCache() {
        if (packMemCache != null) {
            return packMemCache;
        }
        boolean enable = Boolean.parseBoolean(System.getProperty(MEMCHACHE_PACK_ENABLE, "false"));
        if (!enable) {
            return null;
        }
        long[] values = getMemCacheConfig(MEMCHACHE_EXPIRE_PACK, MEMCHACHE_MAX_PACK, MEMCHACHE_MAX_RATE_PACK, 10, 0.35f);
        packMemCache = new PackExpiredMemCache(values[0], values[1]);
        return packMemCache;
    }
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