[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



"  \"tx\" : [               (array of string) The transaction ids\n"
            "     \"transactionid\"     (string) The transaction id\n"
            "     ,...\n"
            "  ],\n"
            "  \"time\" : ttt,          (numeric) The block time in seconds since epoch (Jan 1 1970 GMT)\n"
            "  \"mediantime\" : ttt,    (numeric) The median block time in seconds since epoch (Jan 1 1970 GMT)\n"
            "  \"nonce\" : n,           (numeric) The nonce\n"
            "  \"bits\" : \"1d00ffff\", (string) The bits\n"
            "  \"difficulty\" : x.xxx,  (numeric) The difficulty\n"
            "  \"chainwork\" : \"xxxx\",  (string) Expected number of hashes required to produce the chain up to this block (in hex)\n"
            "  \"nTx\" : n,             (numeric) The number of transactions in the block.\n"
            "  \"previousblockhash\" : \"hash\",  (string) The hash of the previous block\n"
            "  \"nextblockhash\" : \"hash\"       (string) The hash of the next block\n"
            "}\n"
            "\nResult (for verbosity = 2):\n"
            "{\n"
            "  ...,                     Same output as verbosity = 1.\n"
            "  \"tx\" : [               (array of Objects) The transactions in the format of the getrawtransaction RPC. Different from verbosity = 1 \"tx\" result.\n"
            "         ,...\n"
            "  ],\n"
            "  ,...                     Same output as verbosity = 1.\n"
            "}\n"
            "\nExamples:\n"
            + HelpExampleCli("getblock", "\"00000000c937983704a73af28acdec37b049d214adbda81d7e2a3dd146f6ed09\"")
            + HelpExampleRpc("getblock", "\"00000000c937983704a73af28acdec37b049d214adbda81d7e2a3dd146f6ed09\"")
        );
    LOCK(cs_main);
    uint256 hash(ParseHashV(request.params[0], "blockhash"));
    int verbosity = 1;
    if (!request.params[1].isNull()) {