Performance of ShowBlocks: store all blocks and txs in memory

[ageis]

The SQLite file of 111765 blocks and 585586 transactions is only 258MB, so I think there's a chance we can get by placing the entire blockchain in memory. SQLite also allows you to create and work from an in-memory database, but it would be destroyed when the process is killed.

Other options are to look at stuff like memcached or Redis.