Allow store one copy of tables
names for many node backups.
This setup will NOT clean these tables as it not possible to figure on-the-fly which is empty.
For cleanups such setup need to create two-pass tool:
Vacuum of mega-block-hash tables will take eternity.
To speedup things - need to split hash/block tables in partitions. Preferably by ~2Gb (1950Mb) file size. If create new big partition file - need to resync data between all partitions. Or resync on-the-fly.
For MySQL/PgSQL - need to startup two instances: for block/hash/names, and for node backup.