updating witness_missed_blocks_apr_cache is slow
This is probably an already known issue, but documenting it so the info doesn't get lost. The refresh of this cache averages around 200s. I suppose it is scanning the account operations of all witnesses and witnesses are known to generate a huge number of opertions, so it isn't surprising it takes a long time.
This may not be a high priority issue as the time doesn't matter but so much because it is not part of an api call, it just updates a cache used by api calls. But eventually the algorithm probably needs to be replaced by some incremental algorithm that doesn't re-scan entire account history every time.
I'm also not sure if this doesn't end up tying up the reversible table longer than is needed (if so, one simple trick could be to only process the irreversible table until an incremental algorithm is desigend).