MultiChain Developer Q&A - Recent questions tagged tx

Missing exactly one transaction after "merkleblock"-message

Mon, 04 May 2020 17:30:01 +0000

Hi,

I've come across an "issue" where after a "merkleblock"-message Multichain leaves out exactly one of transactions in the following "tx"-messages. I'm not sure whether this is intended behavior and I just misunderstood the Bitcoin documentation or an actual problem.

Here's the setup:
I'm using Multichain as a single full node in combination with a browser based Bitcoin SPV node (bcoin).
When the SPV node creates and announces a new unconfirmed transaction Multichain receives, validates and adds it to the next block as expected. Multichain proceeds to announce the new block ("inv"-message) and the SPV node requests it ("getdata"-message) as should be. In response, Multichain sends a "merkleblock"-message to the SPV node as well as separate "tx"-messages for all but one transaction of the newly created block.

From the Bitcoin documentation [1]:
The merkleblock message is a reply to a getdata message which requested a block using the inventory type MSG_MERKLEBLOCK. It is only part of the reply: if any matching transactions are found, they will be sent separately as tx messages.

And from [2]:
After a merkleblock, transactions matching the bloom filter are automatically sent in tx messages.

Since I didn't set a bloom filter I expected one "tx"-message for every transaction that is included in the block. However, Multichain leaves out exactly one of those transactions.
I've noticed that the missing transaction is always the one the SPV node announced earlier. My best guess here is that Multichain assumes the SPV node won't need that transaction a second time since it announced it in the first place? Is this intended behavior by Multichain or am I missing something here?

Thanks in advance and best regards

[1] https://bitcoin.org/en/developer-reference#merkleblock
[2] https://en.bitcoin.it/wiki/Protocol_documentation#filterload.2C_filteradd.2C_filterclear.2C_merkleblock

How to improve tx/s performance

Sat, 20 Apr 2019 09:07:48 +0000

Hi,

i have deployed a Multichain blockchain on my desktop pc (i5@3.20Ghz, 8GB RAM) with 2 nodes. The performance is really low, since i am getting like 1 tx/s.

My params configurations looks as follows:

target-block-time = 2
maximum-block-size = 1000000000
anyone-can-send = true
anyone-can-receive = true
setup-first-blocks = 60
mining-diversity = 0.5

max-std-tx-size = 10000

Also i am using Windows cmd with a for loop to generate transactions:

for /l %x in (1,1, 10) do multichain-cli blockchain2 sendassettoaddress 1CtfVVPeXsvfdo9C1X37sh3B7hQxgNPsyAjEU2 multicoin 1

I would like to get the maximum tx/s out of my resources, can you help me on identifying the bottlenecks?

Thank you!

Error tx open

Thu, 02 Mar 2017 05:12:07 +0000

177.133.187.151 - - [02/Mar/2017 05:10:56] "GET /KriptaChain/recent?random=0.4112699652628333 HTTP/1.1" 200 469
Traceback (most recent call last):
  File "/usr/lib/python2.7/wsgiref/handlers.py", line 85, in run
    self.result = application(self.environ, self.start_response)
  File "/home/ubuntu/multichain-explorer/Mce/abe.py", line 321, in __call__
    handler(page)
  File "/home/ubuntu/multichain-explorer/Mce/abe.py", line 1194, in handle_tx
    return abe.show_tx(page, tx)
  File "/home/ubuntu/multichain-explorer/Mce/abe.py", line 1668, in show_tx
    row_to_html(txout, 'o', 'i', 'Not yet redeemed')
  File "/home/ubuntu/multichain-explorer/Mce/abe.py", line 1595, in row_to_html
    abe.show_tx_row_to_html_impl(chain, body, asset_txid_dict, binscript, script_type)
  File "/home/ubuntu/multichain-explorer/Mce/abe.py", line 1474, in show_tx_row_to_html_impl
    opreturn_type, val = util.parse_op_return_data(data, chain)
UnboundLocalError: local variable 'data' referenced before assignment