[gmaxwell@argonaut src]$ ./bitcoin-cli getblockstats 101
{
  "avgfee": 0,
  "avgfeerate": 0,
  "avgtxsize": 0,
  "blockhash": "00000000b69bd8e4dc60580117617a466d5c76ada85fb7b87e9baea01f9d9984",
  "feerate_percentiles": [
    0,
    0,
    0,
    0,
    0
  ],
  "height": 101,
  "ins": 0,
  "maxfee": 0,
  "maxfeerate": 0,
  "maxtxsize": 0,
  "medianfee": 0,
  "mediantime": 1231657185,
  "mediantxsize": 0,
  "minfee": 0,
  "minfeerate": 0,
  "mintxsize": 0,
  "outs": 1,
  "subsidy": 5000000000,
  "swtotal_size": 0,
  "swtotal_weight": 0,
  "swtxs": 0,
  "time": 1231661741,
  "total_out": 0,
  "total_size": 0,
  "total_weight": 0,
  "totalfee": 0,
  "txs": 1,
  "utxo_increase": 1,
  "utxo_size_inc": 117
}
[gmaxwell@argonaut src]$ ./bitcoin-cli getblockstats 100000
error code: -8
error message:
One or more of the selected stats requires -txindex enabled

Stats that require txindex should always fail if txindex isn't enabled and the stat is requested, and those stats should not be offered by default.

Also, although the help says it will accept a '1. "hash_or_height"     (string or numeric, required) The block hash or height of the target block', that doesn't seem to work regardless of how I quote it.

[gmaxwell@argonaut src]$ ./bitcoin-cli getblockstats "0000000000000000001b98c07fca289e1ca3358aeabdcca9b7f7ba704d83a3d4"
error: Error parsing JSON:0000000000000000001b98c07fca289e1ca3358aeabdcca9b7f7ba704d83a3d4



{
    if (request.fHelp || request.params.size() > 0) {
        throw std::runtime_error(
            "syncwithvalidationinterfacequeue\n"
            "\nWaits for the validation interface queue to catch up on everything that was there when we entered this function.\n"
            "\nExamples:\n"
            + HelpExampleCli("syncwithvalidationinterfacequeue","")
            + HelpExampleRpc("syncwithvalidationinterfacequeue","")
        );
    }
    SyncWithValidationInterfaceQueue();
    return NullUniValue;
}
static UniValue getdifficulty(const JSONRPCRequest& request)
{
    if (request.fHelp || request.params.size() != 0)
        throw std::runtime_error(
            "getdifficulty\n"
            "\nReturns the proof-of-work difficulty as a multiple of the minimum difficulty.\n"
            "\nResult:\n"
            "n.nnn       (numeric) the proof-of-work difficulty as a multiple of the minimum difficulty.\n"
            "\nExamples:\n"
            + HelpExampleCli("getdifficulty", "")
            + HelpExampleRpc("getdifficulty", "")
        );
    LOCK(cs_main);
    return GetDifficulty(chainActive.Tip());
}
static std::string EntryDescriptionString()