What do these memory configurations in debug.log of BitCoin Core represent?

In the debug.log file of BitCoin Core, the cache configuration is described as follows.

Cache configuration:
  Using 2.0 MiB for block index database
  Using 8.0 MiB for chain state database
  Using 441.0 MiB for in-memory UTXO set (plus up to 286.1 MiB of unused mempool space)

What is the 8MB cache space allocated for chainstate database here used for? What is the difference and connection between it and the in-memory UTXO set?