Instead of having a magic 10 open files, we now have a scheduled
run that closes all mapped files 30 seconds after last usage.
This allows many files to be opened with extremely low overhead and
cost (they are not actually loaded until needed, and even then only
per 4K page).
We inherited the design from Core that you can put in your config
file which chain you will follow (testnet, regtest).
This has the effect that you can't have different config files for
different chains and that we always read the fallback location for
all chains. Especially the last one is just harmful.
So, regtest/testnet can only be selected from commandline.
If you choose one of those, it will look for a flowee.conf in the
related subdir (flowee/regtest/flowee.conf for instance) and NOT
for the global one. The global one is only ever read for mainnet.
When pruning we sort leafs by txid / output and refrain from
writing the txid repeatedly for outputs of the same tx.
Additionally, use the fact that we only ever get to a leaf via
a bucket and since the first 64 bits of a txid is there, skip
repeating them when writing to disk.
Last, make pruning have different strategies.
This should shrink the utxo by about 40%
Actually delete the asio io_service when we are done with it since that
will delete any left over tasks in the queue.
This makes deletion order more predictable.
After we extract all block-headers from the files and we then shut down
the node this makes sure that we avoid thinking we finished because
there are no more jobs.
This so that a restarting node has the opportunity to continue indexing.
* remove unused code
* reorg code to make the access to disk be outside the mutex
* add detection of slow disk-writes and slow down data coming in
* Update and fix the rmHint
TomZ