MultiChain Developer Q&A - Recent questions tagged mempool

Slow reindex probably due to high mempool

Tue, 16 Sep 2025 10:20:29 +0000

Hi,

My node has been reindexing for 3 weeks. Right now it has synchronized/checked 5kk out of 8kk blocks.

Mempool is very high, around 1.1k. My question is, what's the best way to handle this situation and what will happen if I restart multichain service during reindex process?

I'm not concerned about losing mempool since I can replicate the value(docs hash) of transactions. My primary goal is to get the node running correctly asap. Unfortunately, I do not have backup/snapshot of the node.

In advance, thank you for an assistance.

Nodes not mining and -1 in synced headers and synced blocks

Sun, 29 Nov 2020 07:55:29 +0000

Hello,

I checked the getpeerinfo command on a blockchain running from past 8 months I found the synced blocks and synced headers of one of the peers is -1 and the another peer is not syncing the mempool. The mining seems to have paused as well, leaving a lot of transactions in the mempool which are not being mined and synced.

{
        "id" : 16,
        "addr" : "10.0.4.238:57148",
        "addrlocal" : "11.0.2.19:6004",
        "services" : "0000000000000001",
        "lastsend" : 1606634315,
        "lastrecv" : 1606634315,
        "bytessent" : 64775843,
        "bytesrecv" : 58707709,
        "conntime" : 1597433750,
        "pingtime" : 0.036274,
        "version" : 70002,
        "subver" : "/MultiChain:0.2.0.10/",
        "handshakelocal" : "1K73Tko1w9ZVPaSL5L5RHFEBnbNVWTHB5c8owZ",
        "handshake" : "1WmQoWUM5GjErTH1KnjQjDSThGEFapx6GMqTGQ",
        "inbound" : true,
        "startingheight" : 6738,
        "banscore" : 0,
        "synced_headers" : -1,
        "synced_blocks" : -1,
        "inflight" : [
        ],
        "whitelisted" : false
    },
    {
        "id" : 17,
        "addr" : "10.0.2.218:41652",
        "addrlocal" : "11.0.2.19:6004",
        "services" : "0000000000000001",
        "lastsend" : 1606634313,
        "lastrecv" : 1606634313,
        "bytessent" : 6121210,
        "bytesrecv" : 54235,
        "conntime" : 1606633541,
        "pingtime" : 0.078501,
        "version" : 70002,
        "subver" : "/MultiChain:0.2.0.10/",
        "handshakelocal" : "1K73Tko1w9ZVPaSL5L5RHFEBnbNVWTHB5c8owZ",
        "handshake" : "1UgYYerpfmaV5R1sMpWSci6ymP4HD25G2FPHAs",
        "inbound" : true,
        "startingheight" : 6738,
        "banscore" : 0,
        "synced_headers" : -1,
        "synced_blocks" : -1,
        "inflight" : [
        ],
        "whitelisted" : false
    }

There are a lot of transactions in the mempool of this node which are not getting cleared, the debug.log ends up with

2020-11-29 07:32:08 MultiChainMiner: Block Found - 00bae732a4e336dce3d98613735b74d0cf3f9ccd74a166313bffa2972b556713, prev: 00ede3b542cf0a2ec323bbb547fe7d7c58e56e1969f11970c8f118395e914428, height: 6739, txs: 1312
2020-11-29 07:32:08 VerifyBlockMiner: Permission denied for miner 1K73Tko1w9ZVPaSL5L5RHFEBnbNVWTHB5c8owZ received in block signature
2020-11-29 07:32:08 VerifyBlockMiner: Block 00bae732a4e336dce3d98613735b74d0cf3f9ccd74a166313bffa2972b556713 (height 6739) miner verification failed
2020-11-29 07:32:08 ERROR: ProcessNewBlock : AcceptBlock FAILED
2020-11-29 07:32:08 ERROR: MultiChainMiner : ProcessNewBlock, block not accepted
2020-11-29 07:32:10 MultiChainMiner: Block Found - 00eae7e02fe799d07e969164b2b098573d6da5efa11d362483fcd007aa71b740, prev: 00ede3b542cf0a2ec323bbb547fe7d7c58e56e1969f11970c8f118395e914428, height: 6739, txs: 1312
2020-11-29 07:32:11 VerifyBlockMiner: Permission denied for miner 1K73Tko1w9ZVPaSL5L5RHFEBnbNVWTHB5c8owZ received in block signature
2020-11-29 07:32:11 VerifyBlockMiner: Block 00eae7e02fe799d07e969164b2b098573d6da5efa11d362483fcd007aa71b740 (height 6739) miner verification failed
2020-11-29 07:32:11 ERROR: ProcessNewBlock : AcceptBlock FAILED
2020-11-29 07:32:11 ERROR: MultiChainMiner : ProcessNewBlock, block not accepted

all the three nodes have mining permission, with mining diversity set to 0.66.

Tried stopping and restarting the nodes except the one with mempool, but nothing different happened.

Thank You

Nodes not mining

Sat, 18 Jul 2020 12:12:52 +0000

The mining in a blockchain has unexpectedly stopped, I had a blockchain running for about a couple of months, the blockchain has three nodes all with mining permissions, and mining diversity set to 0.66.

The blockchain was working fine but today I noticed excess memory consumption by the blockchain, on closer inspection I found that the mining has stopped about a month ago, and the mempool is filled with about 4000 transactions.

All three nodes are still connected and broadcasting new transactions to each other but none of the transactions is getting mined, the last block was mined on 24th June 2020.

In getinfo api call, the mining paused parameter is false.

This is the debug log, which also shows something different happening after 24th june 2020

2020-06-24 23:32:30 ResendWalletTransactions()
2020-06-24 23:32:39 UpdateTip: new best=00930c22e713129df7458d6c5e20ca3de5c17ec4ff1ba0b175f489734c4f73b2 height=31160 log2_work=22.927454 tx=34372 date=2020-06-24 23:31:24 progress=1.000000 cache=0
2020-06-24 23:32:41 MultiChainMiner: Block Found - 002120d5c508d36fb47ebc1ebf5f63fa2a259288acc299834d41d2c5b0820b70, prev: 00930c22e713129df7458d6c5e20ca3de5c17ec4ff1ba0b175f489734c4f73b2, height: 31161, txs: 1
2020-06-24 23:32:41 UpdateTip: new best=002120d5c508d36fb47ebc1ebf5f63fa2a259288acc299834d41d2c5b0820b70 height=31161 log2_work=22.9275 tx=34373 date=2020-06-24 23:32:41 progress=1.000000 cache=0
2020-06-24 23:33:03 ResendWalletTransactions()
2020-06-26 16:18:21 CommitTransaction: 1f1ab826af80026512b92be1a9c515722405e2788e5cac536ab3b94a761e3a09, vin: 1, vout: 2
2020-06-26 16:25:02 CommitTransaction: b9f51c3f27fdb2039a5f6dbb3567206dbdb5d0dce0f5416fa0a1ce2b9330b05e, vin: 1, vout: 2
2020-06-26 16:25:12 CommitTransaction: 38083a29ced1dbf2db12f18241f8ef9ebf10d04252af0020f2b8b36df7d35323, vin: 1, vout: 2
2020-06-26 16:25:22 CommitTransaction: bd189c83a98aebd1e06013951fdd69f62ff899646b8b84be84b68b28e482748e, vin: 1, vout: 2
2020-06-26 16:25:52 CommitTransaction: 425b2ca954dc1ab436e891b2daafa7217034f89183915e531eb4013f161a02a8, vin: 1, vout: 2
2020-06-26 16:26:02 CommitTransaction: 961a228bd581f965ca6060486d49b234e14b921ac37aacc8ffc897478297f281, vin: 1, vout: 2
2020-06-26 16:26:12 CommitTransaction: 639bda696c2ae49fe476c7a4ad608610659a20fdad3e035e45be897b30270896, vin: 1, vout: 2
2020-06-26 16:26:22 CommitTransaction: b9308a0699474402195b9e6a39c446c304bf8cbd0a6e070f43a688941efaba8f, vin: 1, vout: 2
2020-06-26 16:27:52 CommitTransaction: eae40ed402ae2a5e6402b49abc6798031ecab43e7d094416e299cfcb785782d8, vin: 1, vout: 2
2020-06-26 16:28:02 CommitTransaction: da7d7ab2668fda67901283335e4db1c412e60dbdcd71bba33100471197364e28, vin: 1, vout: 2
2020-06-26 16:28:12 CommitTransaction: f6335a9cc5b70201217f4d094c481cbaae79e129146a4af59211690d01c70587, vin: 1, vout: 2
2020-06-26 16:28:22 CommitTransaction: 71ddc56bb11311be177d0bdcb3b7bcdfb8c2a00df7a9eb4dc41ae8a486c4d166, vin: 1, vout: 2
2020-06-26 16:28:32 CommitTransaction: 45d3ea3644fe15aff4a7f1597af769a9e15c0bfbef77d6ea9b23627ba840ca20, vin: 1, vout: 2
2020-06-26 16:30:22 CommitTransaction:

.........

2020-07-05 15:32:39 socket sending timeout: 61s
2020-07-05 15:35:15 mchn: Sending minimal parameter set to 10.0.2.218:47216
2020-07-05 15:35:15 receive version message: /MultiChain:0.2.0.10/: version 70002, blocks=31161, us=11.0.2.19:6011, peer=44
2020-07-05 15:35:15 mchn: Connection from 1LWFDzTX9GHwHdpx8zBLExZbwAevCGC8s3EuVS received on peer=44 in verack
2020-07-05 15:35:15 mchn: Connection from 1LWFDzTX9GHwHdpx8zBLExZbwAevCGC8s3EuVS received on peer=44 in verackack (10.0.2.218:47216)
2020-07-05 15:35:15 mchn: Parameter set from peer=44 verified
2020-07-05 15:35:16 mchn: Synced with node 44 on block 31161 - requesting mempool
2020-07-05 15:35:16 mchn: Sending minimal parameter set to 10.0.4.238:6011
2020-07-05 15:35:16 receive version message: /MultiChain:0.2.0.10/: version 70002, blocks=31160, us=11.0.2.19:58198, peer=45
2020-07-05 15:35:16 mchn: Connection from 149kFCMKAenKXZAcENGLD7FMB5BvuXt1JhHGSb received on peer=45 in verack
2020-07-05 15:35:16 mchn: Connection from 149kFCMKAenKXZAcENGLD7FMB5BvuXt1JhHGSb received on peer=45 in verackack (10.0.4.238:6011)
2020-07-05 15:35:16 mchn: Parameter set from peer=45 verified
2020-07-05 19:31:50 CommitTransaction: 0213d891653686ee1dc9ba5153077aa73c7734abe8cd90a424a3f5ce07b71051, vin: 1, vout: 2
2020-07-05 19:32:09 CommitTransaction: e617efe2efee075b85fdcd0ce6ac641a22e19e5e4f49cb8f64c7c2542f2a95d0, vin: 1, vout: 2
2020-07-05 19:35:08 CommitTransaction: 61ee58ce6c5fd3b1e2a2a8e858709d6196c5f832df7dc090d494f8f5517d6937, vin: 1, vout: 2
2020-07-06 04:55:41 CommitTransaction: 3a02331bea3751f9ccaf3853da3d0bbd45ae066b51885bd07a2518eedb032bdd, vin: 1, vout: 2
2020-07-06 05:11:08 CommitTransaction: cb20a200e4be2321faf58ebcfddcdd6d6de4745f0ae08cb7d4581c410e56dd43, vin: 1, vout: 2
2020-07-06 05:14:39 CommitTransaction: 1b695abd3ec00e89c84434486ab8f3542b5a7f1e4985a27fd48f2f2b87497364, vin: 1, vout: 2
2020-07-06 05:26:15 CommitTransaction: 4c732e38089e3006fe91556bb439033962bd3ed9bae38bfb45f151656de95d0c, vin: 1, vout: 2
2020-07-06 05:29:38 CommitTransaction: acfd840431885ea2b2c4744dbc5380e91a50890128e164ac2a5d9175ec25f5b8, vin: 1, vout: 2
2020-07-06 05:32:59 CommitTransaction: 405f1729041503fa7a6af5d86851de1fb80d60a05040e4f5b49a0551202d7023, vin: 1, vout: 2
2020-07-06 05:50:54 CommitTransaction: 34f0f285471d4b1e0ace1b42b94df6992ab7f2130b1e7ceb7a80d9018e826097, vin: 1, vout: 2
2020-07-06 06:06:15 CommitTransaction: 36b7c44a74619a98acbd1018179b26c8aa47b66edc03e6e76bf38ff316372d9d, vin: 1, vout: 2
2020-07-06 06:06:32 CommitTransaction: 257f061dc05453f11f1ce6116d29df8336893e220b006f4d64b7b9f0bc5c97be, vin: 1, vout: 2
2020-07-06 06:19:55 CommitTransaction: 71596557511585e33d0809f3182165232e7a4facb34c8a35cdf5e437000e1f98, vin: 1, vout: 2
2020-07-06 06:21:25 CommitTransaction: 424815aa076186c4fd8ca66412371ebb37657513858b85b6314dbfd52745834d, vin: 1, vout: 2
2020-07-06 06:24:13 CommitTransaction: bb770909698bf71d99f2e02a677bd58748878b7f395f119156cd7f7088a93b3e, vin: 1, vout: 2
2020-07-06 06:27:54 CommitTransaction: 080825c10bd21852a35f21c5246ef39e2e15ab5c4e969993cb37c398b5879cf8, vin: 1, vout: 2
2020-07-06 06:45:58 CommitTransaction: 0c0837454310870bda106667b26951d9663517697f3640eab1ce526a7f6f7437, vin: 1, vout: 2
2020-07-06 06:57:58 CommitTransaction: 1fc900bbb1b451d086d245390dc105f1e63462c0c1a7d94044d95be66b370c8f, vin: 1, vout: 2
2020-07-06 06:58:09 CommitTransaction: 240a1a82dcd2ec4b224854ddbfcaba036e1992df3d8543ef409df4908ab067b6, vin: 1, vout: 2
2020-07-06 08:41:09 CommitTransaction: 433eea579db4969491960d4856c1d7938f042d9330dc6766c77ba937cb622876, vin: 1, vout: 2
2020-07-06 08:41:29 CommitTransaction: e240a48e37eb9bbac01048bb39e10df98ae2bfb8e73e194f21604c75d3f2dde1, vin: 1, vout: 2
2020-07-06 08:45:55 CommitTransaction: 4ac900ac0137b28767e0ad708ef6e335b9e1b83b3e825390eb98ed7a8e5f527e, vin: 1, vout: 2
2020-07-06 08:47:44 CommitTransaction: 7b309d628c715f631d94fec1c50c5732f3bf4423c6d9615080865624d24c559e, vin: 1, vout: 2
2020-07-06 08:48:30 CommitTransaction: 7bd43c5e4ff5152a7195ba9d0e288a566c4e80041ed31074fa5613499e231192, vin: 1, vout: 2
2020-07-06 08:49:13 CommitTransaction: 411ec0d859f8e3183e3b54782f4214e2d4e26c6ea8806247f20932f864ed4570, vin: 1, vout: 2
2020-07-06 08:49:34 CommitTransaction: d81d15d5c67b3ecf190271121491871b5226278a40bf7cf485be4907d8393d8b, vin: 1, vout: 2

Did not post the full log as the logs are quite a lot. The logs end with commit transaction

Not able to find the exact cause of the problem.

Thanks

Problem: In my MultiChain-Explorer the newest transactions are showing "Mempool" in the confirmations section

Wed, 11 Dec 2019 15:20:15 +0000

I´ve a few mompool transactions in my Explorer-History. Do you know how to get them confirmed automatically and stop them beeing in the mempool?

Thank you already.

Restarting a node with unconfirmed txs - fault tolerance

Wed, 11 Apr 2018 19:57:09 +0000

We are testing Multichain as a DB for a system that will receive high load from IoT devices and I'm looking into testing its data fault tolerance.

When txs are received in a node (talking about streams) but not broadcasted yet (not confirmed/mined) and the node is stopped - what happens? When the node is started again - is the data still there (in the mempool) and does it get broadcasted automatically?

I would like to test these scenarios, but I am unsure how exactly, since the txs get confirmed and broadcasted immediately.

Could you give me some short answer on the questions above and maybe suggest how to test this scenario and its fault-tolerance?

getmempoolinfo details

Fri, 17 Nov 2017 09:16:18 +0000

Hi team,

From the documentation and data available on the internet I can vaguely put the size is the number of transactions not being confirmed yet on the blockchain. Which makes sense as it grows when I put load and gradually decreases again. What is confusing me is the bytes field, what does this mean? The bitcoin-cli answer didn't satisfy me. And why doesn't it decrease again? With the below reading is my node endangered to go out of memory. I 'm running mutichain on a 1 GB node.

{"method":"getmempoolinfo","params":[],"id":1,"chain_name":"chain1"}
{
"size" : 1,
"bytes" : 14819
}

Thanks,

Ashish

Transactions stay unconfirmed - error on asset commit

Wed, 12 Apr 2017 13:56:30 +0000

Hi multichain team,

I'm doing an internship, working with Multichain.

I want to issue some assets with (a lot of) custom field(s). I searched for topics about metadata's maximum size and I found a few topics saying that the maximum size was around 8MB. I wanted to test it. When I reach 75 custom fields, the transaction stay in the memory pool and there's no further confirmation for any other transaction, but I don't think the mining stops.

Here's what I get in my docker log :

I tried to increase max-std-element-size, max-std-op-return-size, max-std-tx-size.

The transaction is around 8500 kB.

Let me know if you need more informations, thanks a lot.