# Two block reorg at height 941880 **URL:** https://bnoc.xyz/t/two-block-reorg-at-height-941880/97 **Category:** forks **Tags:** fork **Created:** [March 23, 2026, 4:25pm UTC](https://bnoc.xyz/t/two-block-reorg-at-height-941880/97 "2026-03-23T16:25:58Z") **Posts on this page:** 20 **Page:** 1
### Author: ![b10c](https://bnoc.xyz/user_avatar/bnoc.xyz/b10c/32/4_2.png) [@b10c](https://bnoc.xyz/u/b10c) #### Post date: [March 23, 2026, 4:25pm UTC](https://bnoc.xyz/t/two-block-reorg-at-height-941880/97/1 "2026-03-23T16:25:59Z")
We just had a rare-ish two block reorg where Foundry mined a couple of blocks in a row winning a two block long race against AntPool and ViaBTC. ![image](https://bnoc.xyz/uploads/default/original/1X/db4aa48a2308e78a053eea4463028819682de25d.png) Foundry ended up mining seven blocks in a row: ![image](https://bnoc.xyz/uploads/default/original/1X/bdbe2ede3185fd40f8ea32f3399aaf94f5c35130.png) The stale blocks are: ```auto 00000000000000000001b3ff8b13e57c3ec1eca3ba7d2937edbd9f219eb2d9f3 (AntPool) at height 941881 00000000000000000000c81cbf94a12ca498e72eb8530f7061c8746cf9687b2e (ViaBTC) at height 941882 ``` While Foundry mined the following blocks to win the race: ```auto 00000000000000000000bd4930a5982911e7749eb491886206e71abdc1ec0cc6 (Foundry) at height 941881 00000000000000000000724eac69a18c6699c9f7aaab24bcf18beb2723ccadd2 (Foundry) at height 941882 000000000000000000009c9acd0bc3207fa181f79f8573bf27d8a81d1ef3aa8e (Foundry) at height 941883 ``` ---
### Author: ![jungly](https://bnoc.xyz/user_avatar/bnoc.xyz/jungly/32/141_2.png) [@jungly](https://bnoc.xyz/u/jungly) #### Post date: [March 23, 2026, 4:43pm UTC](https://bnoc.xyz/t/two-block-reorg-at-height-941880/97/2 "2026-03-23T16:43:27Z")
Can you share the timestamps on those blocks or even the headers if possible? Am wonder if this was a result of network latency? ---
### Author: ![b10c](https://bnoc.xyz/user_avatar/bnoc.xyz/b10c/32/4_2.png) [@b10c](https://bnoc.xyz/u/b10c) #### Post date: [March 23, 2026, 4:54pm UTC](https://bnoc.xyz/t/two-block-reorg-at-height-941880/97/3 "2026-03-23T16:54:19Z")
Welcome! I just added the headers and full blocks to the stale-block dataset: [add: stale blocks for 941881 & 941882 by 0xB10C · Pull Request #90 · bitcoin-data/stale-blocks · GitHub](https://github.com/bitcoin-data/stale-blocks/pull/90) Will check the arrival times on those four too. ---
### Author: ![murchandamus](https://bnoc.xyz/user_avatar/bnoc.xyz/murchandamus/32/142_2.png) [@murchandamus](https://bnoc.xyz/u/murchandamus) #### Post date: [March 23, 2026, 4:56pm UTC](https://bnoc.xyz/t/two-block-reorg-at-height-941880/97/4 "2026-03-23T16:56:56Z")
You can see them on [fork.observer](https://fork.observer), just click the blocks for details: Stale chaintip: 941881 — 1774280975 941882 — 1774281079 Best chain: 941881 — 1774280987 941882 — 1774281085 Note that the timestamps only need to be accurate within ±2h, so more interesting would be the arrival times instead of the timestamps. ![image](https://bnoc.xyz/uploads/default/original/1X/fbfe92833e14b86cd576846a79e3208977835fd9.png) ---
### Author: ![b10c](https://bnoc.xyz/user_avatar/bnoc.xyz/b10c/32/4_2.png) [@b10c](https://bnoc.xyz/u/b10c) #### Post date: [March 23, 2026, 5:07pm UTC](https://bnoc.xyz/t/two-block-reorg-at-height-941880/97/5 "2026-03-23T17:07:49Z")
I found it interesting that boerst’s stratum-work did not see any stratum jobs from Foundry mining on their winning blocks. See e.g. [941882 on stratum.work](https://stratum.work/height/941882). Maybe they were only mining on them in one region, and stratum-work is connected to a different one, or they kept quite about them (i.e. selfish mining), or it’s a bug on stratum-work 🙂 ---
### Author: ![jungly](https://bnoc.xyz/user_avatar/bnoc.xyz/jungly/32/141_2.png) [@jungly](https://bnoc.xyz/u/jungly) #### Post date: [March 23, 2026, 7:53pm UTC](https://bnoc.xyz/t/two-block-reorg-at-height-941880/97/7 "2026-03-23T19:53:03Z")
Yup, I am just hoping these pool operators are running sensible clocks - if not using ntp. I looked into this cause I am interested in the uncles probability in p2poolv2. If we look at the fork monitor, it looks like if blocks are within 15-30 seconds of each other it results in a fork. This makes me think if we can get the mean/stddev on the fork blocks timestamps deltas Again, assuming clock drift is not too high. It’ll be fascinating to see how this delta changes between different pairs of pools. Detect friends and enemies 🙂 ---
### Author: ![b10c](https://bnoc.xyz/user_avatar/bnoc.xyz/b10c/32/4_2.png) [@b10c](https://bnoc.xyz/u/b10c) #### Post date: [March 23, 2026, 8:53pm UTC](https://bnoc.xyz/t/two-block-reorg-at-height-941880/97/8 "2026-03-23T20:53:04Z")
There is data on block arrival times and block header timestamps in [GitHub - bitcoin-data/block-arrival-times: A public Bitcoin Block Arrival Time Dataset licensed under CC0. · GitHub](https://github.com/bitcoin-data/block-arrival-times) if you want to compare it over time. @willcl-ark recently shared this plot with me showing 12s-21s deltas on average: ![grafik](https://bnoc.xyz/uploads/default/original/1X/83e911341464641dad799bcc24796aa8b8c1c88f.jpeg) (which makes sense since most pools send out new jobs to miners in 30s intervals) ---
### Author: ![jungly](https://bnoc.xyz/user_avatar/bnoc.xyz/jungly/32/141_2.png) [@jungly](https://bnoc.xyz/u/jungly) #### Post date: [March 23, 2026, 11:18pm UTC](https://bnoc.xyz/t/two-block-reorg-at-height-941880/97/9 "2026-03-23T23:18:42Z")
Yeah, but they should also send a new job immediately on seeing a new block. Unless of course there are some strategies they use to detect how to react to blocks from different pools. Might be interesting to uncover 🙂 Thanks for that link to the data. We don’t see the pool name there, right? Do you think we can include that for the data from now on? Or it might be in another data set somewhere that I can join. We want to get the pool names for the orphan blocks too. Sorry, am new to all your work, so probably asking naive questions. EDIT: Just this: [Offer: Stale block dataset](https://bnoc.xyz/t/offer-stale-block-dataset/13) ---
### Author: ![ajtowns](https://bnoc.xyz/user_avatar/bnoc.xyz/ajtowns/32/64_2.png) [@ajtowns](https://bnoc.xyz/u/ajtowns) #### Post date: [March 24, 2026, 12:31am UTC](https://bnoc.xyz/t/two-block-reorg-at-height-941880/97/10 "2026-03-24T00:31:06Z")
> [@b10c](#): > > We just had a rare-ish two block reorg Per the stale-block repo, previous known two block stale chains: - 788687 / 788686 - 2023-05-08 ; 153k blocks ago - 656478 / 656477 - 2020-11-12 ; 132k blocks earlier - 358999 / 358998 - 2015-06-02 ; 300k blocks earlier - 261199 / 261198 - 2013-10-02 ; 98k blocks earlier So perhaps every ~3 years or 150k blocks? I’m not sure what the maths would be to figure out what to expect there – naively I would have thought you’d square the frequency of one-block reorgs (since you need two blocks in a row to be found almost simultaneously to avoid everyone agreeing on a single tip) which would lead to expecting about a million blocks between 2-block reorgs if we’re seeing 1-block reorgs every thousand blocks, but perhaps you get different results if you model internal delays getting jobs/work distributed between the pool and ASICs separately from network block propagation. My timings for the headers in question were: ```auto 2026-03-23T15:49:53.982265Z Saw new cmpctblock header hash=00000000000000000001b3ff8b13e57c3ec1eca3ba7d2937edbd9f219eb2d9f3 height=941881 peer=14899 peeraddr=45.32.83.173:54302 2026-03-23T15:51:47.008245Z Saw new header hash=00000000000000000000c81cbf94a12ca498e72eb8530f7061c8746cf9687b2e height=941882 peer=38718 peeraddr=124.156.199.113:36184 2026-03-23T15:55:03.500660Z Saw new header hash=000000000000000000009c9acd0bc3207fa181f79f8573bf27d8a81d1ef3aa8e height=941883 peer=36252 peeraddr=65.109.99.249:35498 ``` I didn’t see Foundry’s racing blocks until the reorg. (Which might suggest that 1-block stale blocks are much more common than 1-in-a-thousand, but they just aren’t visible) ---
### Author: ![boerst](https://bnoc.xyz/user_avatar/bnoc.xyz/boerst/32/149_2.png) [@boerst](https://bnoc.xyz/u/boerst) #### Post date: [March 24, 2026, 1:13am UTC](https://bnoc.xyz/t/two-block-reorg-at-height-941880/97/11 "2026-03-24T01:13:54Z")
FWIW, I’m not collecting Foundry’s templates on [https://stratum.work/](https://stratum.work/) - I could never get a working account from them. From the pools that I do collect, I can see that none of the other pools were sending work building on top of Foundry’s 941881 and 941882 blocks. Everyone else was seemingly following the AntPool/ViaBTC chain. ---
### Author: ![b10c](https://bnoc.xyz/user_avatar/bnoc.xyz/b10c/32/4_2.png) [@b10c](https://bnoc.xyz/u/b10c) #### Post date: [March 24, 2026, 3:17pm UTC](https://bnoc.xyz/t/two-block-reorg-at-height-941880/97/12 "2026-03-24T15:17:07Z")
Thanks for clarifying. My Foundry stratum endpoint doesn’t seem to work either. I and I don’t see Foundry listed on [mempool.space/stratum](https://mempool.space/stratum) either. ---
### Author: ![b10c](https://bnoc.xyz/user_avatar/bnoc.xyz/b10c/32/4_2.png) [@b10c](https://bnoc.xyz/u/b10c) #### Post date: [March 24, 2026, 3:34pm UTC](https://bnoc.xyz/t/two-block-reorg-at-height-941880/97/13 "2026-03-24T15:34:29Z")
I looked a bit at the header and block arrival times in the debug.logs of my monitoring nodes. Here, “header” means we either got an INV for this block, saw a `cmpctblock` or a header. Full block means we received the block or successfully reconstructed the block from a compact block. ```auto node block event timestamp 2026-03-23 15:49:53.864840 ian 941881 AntPool header 2026-03-23 15:49:53.903500 dave 941881 AntPool header 2026-03-23 15:49:53.965877 jade 941881 AntPool header 2026-03-23 15:49:53.972246 ian 941881 AntPool full_block 2026-03-23 15:49:53.976826 mike 941881 AntPool header 2026-03-23 15:49:54.029989 owen 941881 AntPool header 2026-03-23 15:49:54.057771 jade 941881 AntPool full_block 2026-03-23 15:49:54.133473 owen 941881 AntPool full_block 2026-03-23 15:49:54.239330 charlie 941881 AntPool header 2026-03-23 15:49:54.241502 bob 941881 AntPool header 2026-03-23 15:49:54.256592 nico 941881 AntPool header 2026-03-23 15:49:54.350779 frank 941881 AntPool header 2026-03-23 15:49:54.356334 alice 941881 AntPool header 2026-03-23 15:49:54.400475 greg 941881 AntPool header 2026-03-23 15:49:54.446445 erin 941881 AntPool header 2026-03-23 15:49:54.457890 bob 941881 AntPool full_block 2026-03-23 15:49:54.582114 hazel 941881 AntPool header 2026-03-23 15:49:54.600324 charlie 941881 AntPool full_block 2026-03-23 15:49:54.604217 mike 941881 AntPool full_block 2026-03-23 15:49:54.612627 nico 941881 AntPool full_block 2026-03-23 15:49:54.715069 dave 941881 AntPool full_block 2026-03-23 15:49:54.764564 greg 941881 AntPool full_block 2026-03-23 15:49:54.812221 kane 941881 AntPool header 2026-03-23 15:49:54.824742 luke 941881 AntPool header 2026-03-23 15:49:54.893326 erin 941881 AntPool full_block 2026-03-23 15:49:55.037321 hazel 941881 AntPool full_block 2026-03-23 15:49:55.238127 frank 941881 AntPool full_block 2026-03-23 15:49:55.440619 luke 941881 AntPool full_block 2026-03-23 15:49:56.627557 alice 941881 AntPool full_block 2026-03-23 15:49:57.215005 kane 941881 AntPool full_block 2026-03-23 15:51:47.052497 nico 941882 ViaBTC header 2026-03-23 15:51:47.058206 alice 941882 ViaBTC header 2026-03-23 15:51:47.061556 charlie 941881 Foundry header 2026-03-23 15:51:47.069931 luke 941882 ViaBTC header 2026-03-23 15:51:47.078155 greg 941882 ViaBTC header 2026-03-23 15:51:47.079686 jade 941882 ViaBTC header 2026-03-23 15:51:47.082866 bob 941881 Foundry header 2026-03-23 15:51:47.083817 alice 941882 ViaBTC full_block 2026-03-23 15:51:47.085359 ian 941882 ViaBTC header 2026-03-23 15:51:47.087298 mike 941882 ViaBTC header 2026-03-23 15:51:47.092817 charlie 941882 ViaBTC header 2026-03-23 15:51:47.098123 erin 941882 ViaBTC header 2026-03-23 15:51:47.101483 frank 941882 ViaBTC header 2026-03-23 15:51:47.102551 jade 941882 ViaBTC full_block 2026-03-23 15:51:47.103210 ian 941882 ViaBTC full_block 2026-03-23 15:51:47.110371 bob 941882 ViaBTC header 2026-03-23 15:51:47.118183 owen 941882 ViaBTC header 2026-03-23 15:51:47.128487 nico 941882 ViaBTC full_block 2026-03-23 15:51:47.130324 kane 941882 ViaBTC header 2026-03-23 15:51:47.132378 greg 941882 ViaBTC full_block 2026-03-23 15:51:47.133369 mike 941882 ViaBTC full_block 2026-03-23 15:51:47.152286 owen 941882 ViaBTC full_block 2026-03-23 15:51:47.160858 erin 941882 ViaBTC full_block 2026-03-23 15:51:47.163834 charlie 941882 ViaBTC full_block 2026-03-23 15:51:47.175300 kane 941882 ViaBTC full_block 2026-03-23 15:51:47.195791 hazel 941882 ViaBTC header 2026-03-23 15:51:47.238768 dave 941882 ViaBTC header 2026-03-23 15:51:47.244357 bob 941882 ViaBTC full_block 2026-03-23 15:51:47.247765 frank 941882 ViaBTC full_block 2026-03-23 15:51:47.263158 hazel 941882 ViaBTC full_block 2026-03-23 15:51:47.536036 dave 941881 Foundry header 2026-03-23 15:51:47.767039 greg 941881 Foundry header 2026-03-23 15:51:48.526856 dave 941882 ViaBTC full_block 2026-03-23 15:51:50.377779 luke 941882 ViaBTC full_block 2026-03-23 15:55:00.641682 bob 941883 Foundry header 2026-03-23 15:55:01.176160 charlie 941882 Foundry header 2026-03-23 15:55:01.191329 dave 941882 Foundry header 2026-03-23 15:55:01.370924 bob 941882 Foundry full_block 2026-03-23 15:55:01.370934 greg 941882 Foundry header 2026-03-23 15:55:01.429284 owen 941882 Foundry header 2026-03-23 15:55:01.711011 greg 941883 Foundry header 2026-03-23 15:55:01.714383 ian 941883 Foundry header 2026-03-23 15:55:01.778498 alice 941883 Foundry header 2026-03-23 15:55:01.780852 owen 941883 Foundry header 2026-03-23 15:55:01.816236 bob 941883 Foundry full_block 2026-03-23 15:55:02.773480 mike 941883 Foundry header 2026-03-23 15:55:03.360435 charlie 941883 Foundry header 2026-03-23 15:55:03.491469 owen 941883 Foundry full_block 2026-03-23 15:55:03.542388 ian 941881 Foundry full_block 2026-03-23 15:55:03.698902 luke 941883 Foundry header 2026-03-23 15:55:03.716347 nico 941881 Foundry header 2026-03-23 15:55:03.716464 nico 941882 Foundry header 2026-03-23 15:55:03.716509 nico 941883 Foundry header 2026-03-23 15:55:04.374432 charlie 941883 Foundry full_block 2026-03-23 15:55:04.456908 dave 941883 Foundry header 2026-03-23 15:55:04.973663 jade 941883 Foundry header 2026-03-23 15:55:05.439823 frank 941883 Foundry header 2026-03-23 15:55:05.886777 erin 941881 Foundry header 2026-03-23 15:55:05.886891 erin 941882 Foundry header 2026-03-23 15:55:05.886936 erin 941883 Foundry header 2026-03-23 15:55:06.085654 dave 941883 Foundry full_block 2026-03-23 15:55:06.374803 erin 941881 Foundry full_block 2026-03-23 15:55:06.747076 erin 941882 Foundry full_block 2026-03-23 15:55:06.801136 mike 941881 Foundry full_block 2026-03-23 15:55:07.071938 erin 941883 Foundry full_block 2026-03-23 15:55:07.172630 hazel 941883 Foundry header 2026-03-23 15:55:07.231769 nico 941881 Foundry full_block 2026-03-23 15:55:07.351077 mike 941882 Foundry full_block 2026-03-23 15:55:07.901623 mike 941883 Foundry full_block 2026-03-23 15:55:08.888249 nico 941882 Foundry full_block 2026-03-23 15:55:09.346723 hazel 941881 Foundry full_block 2026-03-23 15:55:09.965627 jade 941881 Foundry full_block 2026-03-23 15:55:10.133469 hazel 941882 Foundry full_block 2026-03-23 15:55:10.326101 nico 941883 Foundry full_block 2026-03-23 15:55:10.670198 hazel 941883 Foundry full_block 2026-03-23 15:55:10.681589 kane 941883 Foundry header 2026-03-23 15:55:11.418276 ian 941882 Foundry full_block 2026-03-23 15:55:13.304834 greg 941883 Foundry full_block 2026-03-23 15:55:14.318127 jade 941882 Foundry full_block 2026-03-23 15:55:16.414858 ian 941883 Foundry full_block 2026-03-23 15:55:17.683597 jade 941883 Foundry full_block 2026-03-23 15:55:17.998145 alice 941881 Foundry full_block 2026-03-23 15:55:19.254253 luke 941881 Foundry full_block 2026-03-23 15:55:20.573447 kane 941881 Foundry full_block 2026-03-23 15:55:22.239878 alice 941882 Foundry full_block 2026-03-23 15:55:24.322924 alice 941883 Foundry full_block 2026-03-23 15:55:25.850183 frank 941881 Foundry full_block 2026-03-23 15:55:27.524423 kane 941882 Foundry full_block 2026-03-23 15:55:28.616653 luke 941882 Foundry full_block 2026-03-23 15:55:29.847000 frank 941882 Foundry full_block 2026-03-23 15:55:31.190630 frank 941883 Foundry full_block 2026-03-23 15:55:32.942391 kane 941883 Foundry full_block 2026-03-23 15:55:34.202208 luke 941883 Foundry full_block 2026-03-23 16:01:48.751482 charlie 941881 Foundry full_block 2026-03-23 16:01:49.014432 dave 941881 Foundry full_block 2026-03-23 16:01:49.573302 charlie 941882 Foundry full_block 2026-03-23 16:01:50.206303 dave 941882 Foundry full_block 2026-03-23 16:01:54.667334 bob 941881 Foundry full_block 2026-03-23 16:05:03.395825 owen 941881 Foundry full_block 2026-03-23 16:05:04.331536 greg 941881 Foundry full_block 2026-03-23 16:05:04.384588 owen 941882 Foundry full_block 2026-03-23 16:05:05.058914 greg 941882 Foundry full_block ``` I created the following plot from this. ![image](https://bnoc.xyz/uploads/default/original/1X/ec8939f902ec838dcb01e8edf77f927c36f365c7.png) My interpretation of this is: - I received the headers and blocks for 941881 AntPool (red) on all nodes at roughly the same time. - I did not hear about a header or block of 941881 Foundry (blue). - Then, the ViaBTC block and Foundry block 941882 (green) were mined. - I learned about ViaBTCs header and block (orange) on all nodes at roughly the same time. I did not learn about Foundry block 941882 (green). - At the same time, I learned about 941881 Foundry (blue) headers on node `greg`, `bob`, `charlie`, `dave`. I did not learn about the full block. - At a later time, Foundry 941883 (purple, the winning block) was mined and I learned about he Foundry headers and blocks - On some nodes (e.g. `owen` and `greg`), I only learned about the full Foundry blocks \>5min later. ---
### Author: ![zawy12](https://bnoc.xyz/user_avatar/bnoc.xyz/zawy12/32/155_2.png) [@zawy12](https://bnoc.xyz/u/zawy12) #### Post date: [March 24, 2026, 4:09pm UTC](https://bnoc.xyz/t/two-block-reorg-at-height-941880/97/14 "2026-03-24T16:09:42Z")
Foundry released their 1st block (header) immediately after the others’ 2nd block was found. According to their own timestamp on their 1st and 2nd blocks, they found them a few seconds after the others’ 1st and 2nd blocks. They released their 2nd and 3rd at the same time, exactly when the 3rd block was found, winning the race. This is effectively a selfish-mining attack by definition even if it was on “accident” or network hiccup (to the extent “attack” doesn’t imply intentional). But it all seems to point to intentional. Intentional or not, other miners should ignore 2 of Foundry’s blocks. Without enforcing accurate timestamps, this how selfish mining can be made a “nothing burger”. \>50% needs to collude to disincentivize future attacks. If Foundry stops displaying it’s name to prevent this, the only solution is to enforce more accurate timestamps. For example, the rule would be to ignore a header for 600 seconds if its timestamp is more than 15 seconds different from local time (rounded to the nearest 10 s interval) when it arrives. This works because the attacker has to assign a timestamp before he knows when he will need to release it. People complain that this can cause a real problem in real network partitions and it’s true a chain split would last longer if that’s the case, but it will eventually resolve itself based on PoW and which partition has the most hashrate. Rounding to the nearest 10 second interval prevents an attack on the interval. Clocks shouldn’t be off more than 2 seconds which is the other big complaint. Also, miners would have to update the timestamp every 2 seconds. Concerning not being able to get Foundry’s templates, Grok says: Yes, restricting public or easy access to block templates can serve Foundry (or any large pool) if they were engaging in illicit or strategically deviant behavior like selfish mining or block withholding—primarily by reducing detectability and transparency. ---
### Author: ![jungly](https://bnoc.xyz/user_avatar/bnoc.xyz/jungly/32/141_2.png) [@jungly](https://bnoc.xyz/u/jungly) #### Post date: [March 25, 2026, 9:15am UTC](https://bnoc.xyz/t/two-block-reorg-at-height-941880/97/16 "2026-03-25T09:15:39Z")
> [@zawy12](#): > > This is effectively a selfish-mining attack by definition even if it was on “accident” or network hiccup (to the extent “attack” doesn’t imply intentional). But it all seems to point to intentional. Yup. I have reached the same conclusion. Happy to see you are thinking along the same lines. ---
### Author: ![murchandamus](https://bnoc.xyz/user_avatar/bnoc.xyz/murchandamus/32/142_2.png) [@murchandamus](https://bnoc.xyz/u/murchandamus) #### Post date: [March 25, 2026, 7:58pm UTC](https://bnoc.xyz/t/two-block-reorg-at-height-941880/97/17 "2026-03-25T19:58:12Z")
@b10c, it would also be interesting to see this chart split by mining pool. I wonder whether some mining pools that time-roll would have a distinctly different pattern than pools that don’t. Also, I was curious how accurate timestamps of the involved pools are, i.e., whether the timestamps on these concrete competing blocks would lend credence to the idea that Foundry happened to actually find both their blocks right after the competing block as the timestamps seem to hint. ---
### Author: ![matthias](https://bnoc.xyz/user_avatar/bnoc.xyz/matthias/32/39_2.png) [@matthias](https://bnoc.xyz/u/matthias) #### Post date: [March 25, 2026, 8:37pm UTC](https://bnoc.xyz/t/two-block-reorg-at-height-941880/97/18 "2026-03-25T20:37:10Z")
I looked at the arrival times of the inv messages corresponding to these blocks at one of our [monitor nodes](https://www.dsn.kastel.kit.edu/bitcoin/). These monitor nodes receive and log inv messages but do not request the data for headers or blocks. The following list of blocks contains in the first column the point in time at which the monitor received the first inv message for a certain block. The last column shows the number of peers from which the monitor node received the inv message. ```auto 23.03.2026 15:49:53.731 AntPool 941881 inv 9914 23.03.2026 15:49:56.669 Foundry 941881 inv 36 23.03.2026 15:51:46.992 ViaBTC 941882 inv 9904 23.03.2026 15:55:00.579 Foundry 941883 inv 8183 23.03.2026 15:55:05.038 Foundry 941882 inv 26 23.03.2026 16:02:30.817 Foundry 941884 inv 9087 ``` There are two interesting aspects: - An announcement for Foundry’s block at height 941881 was received before any announcement for a block at height 941882 was received. - The monitor node received announcements for Foundry’s blocks at heights 941881 and 941882 only from a few peers. I don’t have an idea why. I would expect that nearly all peers should announce these blocks once they become part of the active chain. EDIT: The majority of nodes announcing these blocks has in common that they announce btcd as their user agent. It seems that Bitcoin Core does not send inv messages for these blocks to our monitor. ---
### Author: ![davidgumberg](https://bnoc.xyz/user_avatar/bnoc.xyz/davidgumberg/32/84_2.png) [@davidgumberg](https://bnoc.xyz/u/davidgumberg) #### Post date: [March 26, 2026, 2:19am UTC](https://bnoc.xyz/t/two-block-reorg-at-height-941880/97/19 "2026-03-26T02:19:52Z")
Looking at debug logs for one of @achow101’s node which was stalled from reorging to the foundry chain until ~16:05, I constructed the following table of events: | Time | Block | Msg/Action | From Peer | To Peer | | --- | --- | --- | --- | --- | | 15:49:53.834 | Antpool 1 | INV | 199 | | | 15:49:53.835 | Antpool 1 | GETHEADERS | | 199 | | 15:49:54.176 | Antpool 1 | HEADERS | 3952229 | | | 15:49:54.176 | Antpool 1 | GETDATA | | 3952229 | | 15:49:54.282 | Antpool 1 | CMPCTBLOCK | 3 | | | 15:49:54.305 | Antpool 1 | GETBLOCKTXN | | 3 | | 15:49:54.356 | Antpool 1 | CMPCTBLOCK | 3952229 | | | 15:49:54.379 | Antpool 1 | GETBLOCKTXN | | 3952229 | | 15:49:54.425 | Antpool 1 | BLOCKTXN | 3 | | | 15:49:54.433 | Antpool 1 | CMPCTBLOCK Reconstructed | 3 | | | 15:49:54.723 | Antpool 1 | Update Tip | | | | 15:50:01.464 | Foundry 1 | INV | 199 | | | 15:50:01.464 | Foundry 1 | GETHEADERS | | 199 | | 15:51:47.071 | Antpool 2 | INV | 199 | | | 15:51:47.071 | Antpool 2 | GETHEADERS | | 199 | | 15:51:47.075 | Antpool 2 | CMPCTBLOCK | 1271642 | | | 15:51:47.08 | Antpool 2 | HEADERS | 1271642 | | | 15:51:47.079 | Antpool 2 | CMPCTBLOCK Reconstructed | | | | 15:51:47.176 | Antpool 2 | UpdateTip | 1271642 | | | 15:51:47.270 | Foundry 1 | HEADERS | 199 | | | 15:55:01.161 | Foundry 2 | INV | 199 | | | 15:55:01.161 | Foundry 2 | GETHEADERS | | 199 | | 15:55:01.358 | Foundry 3 | INV | 199 | | | 15:55:01.583 | Foundry 2 | HEADERS | 199 | | | 15:55:01.583 | Foundry 1 | GETDATA | | 199 | | 15:55:01.583 | Foundry 2 | GETDATA | | 199 | | 15:55:06.356 | Foundry 3 | HEADERS | 8302907 | | | 15:55:06.356 | Foundry 3 | GETDATA | 8302907 | | | 15:55:07.295 | Foundry 3 | BLOCK | 8302907 | | | 16:02:30.919 | Main 4 | INV | 199 | | | 16:02:30.920 | Main 4 | GETHEADERS | | 199 | | 16:02:30.970 | Main 4 | HEADERS | 6312471 | | | 16:02:30.970 | Main 4 | GETDATA | 6312471 | | | 16:02:31.324 | Main 4 | CMPCTBLOCK | 1283269 | | | 16:02:31.342 | Main 4 | GETBLOCKTXN | | 1283269 | | 16:02:32.049 | Main 4 | BLOCKTXN | 1283269 | | | 16:02:32.049 | Main 4 | CMPCTBLOCK Reconstructed | | | | 16:04:49.393 | Main 5 | INV | 199 | | | 16:04:49.393 | Main 5 | GETHEADERS | | 199 | | 16:04:49.595 | Main 5 | HEADERS | 4392345 | | | 16:04:49.595 | Main 5 | GETDATA | | 4392345 | | 16:04:50.220 | Main 5 | BLOCK | | 4392345 | | 16:05:01.590 | Foundry 1 | Block stall timeout, disconnect peer | 199 | | | 16:05:01.612 | Foundry 1 | GETDATA | | 8302907 | | 16:05:01.612 | Foundry 2 | GETDATA | | 8302907 | | 16:05:02.593 | Foundry 1 | BLOCK | 8302907 | | | 16:05:03.322 | Foundry 2 | BLOCK | 8302907 | | | 16:05:03.434 | Antpool 2 | Block Disconnected | | | | 16:05:03.844 | Foundry 1 | Update Tip | | | | 16:05:04.065 | Foundry 2 | Update Tip | | | | 16:05:04.355 | Foundry 3 | Update Tip | | | | 16:05:04.425 | Antpool 1 | Block Disconnected | | | | 16:05:08.862 | Main 4 | Update Tip | | | | 16:05:09.152 | Main 5 | Update Tip | | | > **Table with full log messages** > > | Time | Block | Msg/Action | From Peer | To Peer | Log message | > | --- | --- | --- | --- | --- | --- | > | 15:49:53.834 | Antpool 1 | INV | 199 | | 2026-03-23T15:49:53.834333Z [msghand] [../../src/net\_processing.cpp:4146] [ProcessMessage] [net] got inv: block 00000000000000000001b3ff8b13e57c3ec1eca3ba7d2937edbd9f219eb2d9f3 new peer=199 | > | 15:49:53.835 | Antpool 1 | GETHEADERS | | 199 | 2026-03-23T15:49:53.834575Z [msghand] [../../src/net\_processing.cpp:4190] [ProcessMessage] [net] getheaders (941880) 00000000000000000001b3ff8b13e57c3ec1eca3ba7d2937edbd9f219eb2d9f3 to peer=199 | > | 15:49:54.176 | Antpool 1 | HEADERS | 3952229 | | 2026-03-23T15:49:54.175539Z [msghand] [../../src/net\_processing.cpp:3546] [LogBlockHeader] Saw new header hash=00000000000000000001b3ff8b13e57c3ec1eca3ba7d2937edbd9f219eb2d9f3 height=941881 peer=3952229, peeraddr=[2600:1702:7aa0:10b0:266e:96ff:fe46:9218]:35822 | > | 15:49:54.176 | Antpool 1 | GETDATA | | 3952229 | 2026-03-23T15:49:54.175654Z [msghand] [../../src/net\_processing.cpp:2876] [HeadersDirectFetchBlocks] [net] Requesting block 00000000000000000001b3ff8b13e57c3ec1eca3ba7d2937edbd9f219eb2d9f3 from peer=3952229 | > | 15:49:54.282 | Antpool 1 | CMPCTBLOCK | 3 | | 2026-03-23T15:49:54.280740Z [msghand] [../../src/net\_processing.cpp:3575] [ProcessMessage] [net] received: cmpctblock (27910 bytes) peer=3 \n 2026-03-23T15:49:54.281870Z [msghand] [../../src/blockencodings.cpp:61] [InitData] [cmpctblock] Initializing PartiallyDownloadedBlock for block 00000000000000000001b3ff8b13e57c3ec1eca3ba7d2937edbd9f219eb2d9f3 using a cmpctblock of 27910 bytes | > | 15:49:54.305 | Antpool 1 | GETBLOCKTXN | | 3 | 2026-03-23T15:49:54.305168Z [msghand] [../../src/blockencodings.cpp:178] [InitData] [cmpctblock] Initialized PartiallyDownloadedBlock for block 00000000000000000001b3ff8b13e57c3ec1eca3ba7d2937edbd9f219eb2d9f3 using a cmpctblock of 27910 bytes \n 2026-03-23T15:49:54.305744Z [msghand] [../../src/net.cpp:4078] [PushMessage] [net] sending getblocktxn (93 bytes) peer=3 | > | 15:49:54.356 | Antpool 1 | CMPCTBLOCK | 3952229 | | 2026-03-23T15:49:54.354679Z [msghand] [../../src/net\_processing.cpp:3575] [ProcessMessage] [net] received: cmpctblock (27910 bytes) peer=3952229 \n 2026-03-23T15:49:54.355897Z [msghand] [../../src/blockencodings.cpp:61] [InitData] [cmpctblock] Initializing PartiallyDownloadedBlock for block 00000000000000000001b3ff8b13e57c3ec1eca3ba7d2937edbd9f219eb2d9f3 using a cmpctblock of 27910 bytes | > | 15:49:54.379 | Antpool 1 | GETBLOCKTXN | | 3952229 | 2026-03-23T15:49:54.378914Z [msghand] [../../src/blockencodings.cpp:178] [InitData] [cmpctblock] Initialized PartiallyDownloadedBlock for block 00000000000000000001b3ff8b13e57c3ec1eca3ba7d2937edbd9f219eb2d9f3 using a cmpctblock of 27910 bytes \n 2026-03-23T15:49:54.379443Z [msghand] [../../src/net.cpp:4078] [PushMessage] [net] sending getblocktxn (93 bytes) peer=3952229 | > | 15:49:54.425 | Antpool 1 | BLOCKTXN | 3 | | 2026-03-23T15:49:54.425321Z [msghand] [../../src/net\_processing.cpp:3575] [ProcessMessage] [net] received: blocktxn (21507 bytes) peer=3 | > | 15:49:54.433 | Antpool 1 | CMPCTBLOCK Reconstructed | 3 | | 2026-03-23T15:49:54.432974Z [msghand] [../../src/blockencodings.cpp:228] [FillBlock] [cmpctblock] Successfully reconstructed block 00000000000000000001b3ff8b13e57c3ec1eca3ba7d2937edbd9f219eb2d9f3 with 1 txn prefilled, 4510 txn from mempool (incl at least 0 from extra pool) and 56 txn (21474 bytes) requested | > | 15:49:54.723 | Antpool 1 | Update Tip | | | 2026-03-23T15:49:54.722505Z [msghand] [../../src/validation.cpp:2867] [UpdateTipLog] UpdateTip: new best=00000000000000000001b3ff8b13e57c3ec1eca3ba7d2937edbd9f219eb2d9f3 height=941881 version=0x3092c000 log2\_work=96.137382 tx=1327000957 date=‘2026-03-23T15:49:35Z’ progress=1.000000 cache=218.5MiB(1597395txo) | > | 15:50:01.464 | Foundry 1 | INV | 199 | | 2026-03-23T15:50:01.463926Z [msghand] [../../src/net\_processing.cpp:4146] [ProcessMessage] [net] got inv: block 00000000000000000000bd4930a5982911e7749eb491886206e71abdc1ec0cc6 new peer=199 | > | 15:50:01.464 | Foundry 1 | GETHEADERS | | 199 | 2026-03-23T15:50:01.464206Z [msghand] [../../src/net\_processing.cpp:4190] [ProcessMessage] [net] getheaders (941881) 00000000000000000000bd4930a5982911e7749eb491886206e71abdc1ec0cc6 to peer=199 | > | 15:51:47.071 | Antpool 2 | INV | 199 | | 2026-03-23T15:51:47.070886Z [msghand] [../../src/net\_processing.cpp:4146] [ProcessMessage] [net] got inv: block 00000000000000000000c81cbf94a12ca498e72eb8530f7061c8746cf9687b2e new peer=199 | > | 15:51:47.071 | Antpool 2 | GETHEADERS | | 199 | 2026-03-23T15:50:01.464206Z [msghand] [../../src/net\_processing.cpp:4190] [ProcessMessage] [net] getheaders (941881) 00000000000000000000bd4930a5982911e7749eb491886206e71abdc1ec0cc6 to peer=199 | > | 15:51:47.075 | Antpool 2 | CMPCTBLOCK | 1271642 | | 2026-03-23T15:51:47.074890Z [msghand] [../../src/net\_processing.cpp:3575] [ProcessMessage] [net] received: cmpctblock (5773 bytes) peer=1271642 \n 2026-03-23T15:51:47.075326Z [msghand] [../../src/net\_processing.cpp:3546] [LogBlockHeader] Saw new cmpctblock header hash=00000000000000000000c81cbf94a12ca498e72eb8530f7061c8746cf9687b2e height=941882 peer=1271642, peeraddr=[2600:8801:2f80:ac:f522:7bf5:2ae7:47fd]:60099 \n 2026-03-23T15:51:47.075428Z [msghand] [../../src/blockencodings.cpp:61] [InitData] [cmpctblock] Initializing PartiallyDownloadedBlock for block 00000000000000000000c81cbf94a12ca498e72eb8530f7061c8746cf9687b2e using a cmpctblock of 5773 bytes | > | 15:51:47.08 | Antpool 2 | HEADERS | 1271642 | | 2026-03-23T15:51:47.075326Z [msghand] [../../src/net\_processing.cpp:3546] [LogBlockHeader] Saw new cmpctblock header hash=00000000000000000000c81cbf94a12ca498e72eb8530f7061c8746cf9687b2e height=941882 peer=1271642, peeraddr=[2600:8801:2f80:ac:f522:7bf5:2ae7:47fd]:60099 | > | 15:51:47.079 | Antpool 2 | CMPCTBLOCK Reconstructed | | | 2026-03-23T15:51:47.089420Z [msghand] [../../src/blockencodings.cpp:228] [FillBlock] [cmpctblock] Successfully reconstructed block 00000000000000000000c81cbf94a12ca498e72eb8530f7061c8746cf9687b2e with 1 txn prefilled, 871 txn from mempool (incl at least 1 from extra pool) and 0 txn (0 bytes) requested | > | 15:51:47.176 | Antpool 2 | UpdateTip | 1271642 | | 2026-03-23T15:51:47.175709Z [msghand] [../../src/validationinterface.cpp:182] [UpdatedBlockTip] [validation] Enqueuing UpdatedBlockTip: new block hash=00000000000000000000c81cbf94a12ca498e72eb8530f7061c8746cf9687b2e fork block hash=00000000000000000001b3ff8b13e57c3ec1eca3ba7d2937edbd9f219eb2d9f3 (in IBD=false) | > | 15:51:47.270 | Foundry 1 | HEADERS | 199 | | 2026-03-23T15:51:47.269999Z [msghand] [../../src/net\_processing.cpp:3546] [LogBlockHeader] Saw new header hash=00000000000000000000bd4930a5982911e7749eb491886206e71abdc1ec0cc6 height=941881 peer=199, peeraddr=80.251.125.221:46532 | > | 15:55:01.161 | Foundry 2 | INV | 199 | | 2026-03-23T15:55:01.160946Z [msghand] [../../src/net\_processing.cpp:4146] [ProcessMessage] [net] got inv: block 00000000000000000000724eac69a18c6699c9f7aaab24bcf18beb2723ccadd2 new peer=199 | > | 15:55:01.161 | Foundry 2 | GETHEADERS | | 199 | 2026-03-23T15:55:01.161244Z [msghand] [../../src/net\_processing.cpp:4190] [ProcessMessage] [net] getheaders (941882) 00000000000000000000724eac69a18c6699c9f7aaab24bcf18beb2723ccadd2 to peer=199 | > | 15:55:01.358 | Foundry 3 | INV | 199 | | 2026-03-23T15:55:01.357525Z [msghand] [../../src/net\_processing.cpp:4146] [ProcessMessage] [net] got inv: block 000000000000000000009c9acd0bc3207fa181f79f8573bf27d8a81d1ef3aa8e new peer=199 | > | 15:55:01.583 | Foundry 2 | HEADERS | 199 | | 2026-03-23T15:55:01.583065Z [msghand] [../../src/net\_processing.cpp:3546] [LogBlockHeader] Saw new header hash=00000000000000000000724eac69a18c6699c9f7aaab24bcf18beb2723ccadd2 height=941882 peer=199, peeraddr=80.251.125.221:46532 | > | 15:55:01.583 | Foundry 1 | GETDATA | | 199 | 2026-03-23T15:55:01.583122Z [msghand] [../../src/net\_processing.cpp:2876] [HeadersDirectFetchBlocks] [net] Requesting block 00000000000000000000bd4930a5982911e7749eb491886206e71abdc1ec0cc6 from peer=199 | > | 15:55:01.583 | Foundry 2 | GETDATA | | 199 | 2026-03-23T15:55:01.583148Z [msghand] [../../src/net\_processing.cpp:2876] [HeadersDirectFetchBlocks] [net] Requesting block 00000000000000000000724eac69a18c6699c9f7aaab24bcf18beb2723ccadd2 from peer=199 | > | 15:55:06.356 | Foundry 3 | HEADERS | 8302907 | | 2026-03-23T15:55:06.355712Z [msghand] [../../src/net\_processing.cpp:3546] [LogBlockHeader] Saw new header hash=000000000000000000009c9acd0bc3207fa181f79f8573bf27d8a81d1ef3aa8e height=941883 peer=8302907, peeraddr=67.85.54.88:56666 | > | 15:55:06.356 | Foundry 3 | GETDATA | 8302907 | | 2026-03-23T15:55:06.355875Z [msghand] [../../src/net\_processing.cpp:2876] [HeadersDirectFetchBlocks] [net] Requesting block 000000000000000000009c9acd0bc3207fa181f79f8573bf27d8a81d1ef3aa8e from peer=8302907 | > | 15:55:07.295 | Foundry 3 | BLOCK | 8302907 | | 2026-03-23T15:55:07.294834Z [msghand] [../../src/net\_processing.cpp:4859] [ProcessMessage] [net] received block 000000000000000000009c9acd0bc3207fa181f79f8573bf27d8a81d1ef3aa8e peer=8302907 | > | 16:02:30.919 | Main 4 | INV | 199 | | 2026-03-23T16:02:30.919287Z [msghand] [../../src/net\_processing.cpp:4146] [ProcessMessage] [net] got inv: block 0000000000000000000085ebdcd669c404195dbfeccbee902fc646dadc367a20 new peer=199 | > | 16:02:30.920 | Main 4 | GETHEADERS | | 199 | 2026-03-23T16:02:30.919581Z [msghand] [../../src/net\_processing.cpp:4190] [ProcessMessage] [net] getheaders (941883) 0000000000000000000085ebdcd669c404195dbfeccbee902fc646dadc367a20 to peer=199 | > | 16:02:30.970 | Main 4 | HEADERS | 6312471 | | 2026-03-23T16:02:30.969996Z [msghand] [../../src/net\_processing.cpp:3546] [LogBlockHeader] Saw new header hash=0000000000000000000085ebdcd669c404195dbfeccbee902fc646dadc367a20 height=941884 peer=6312471, peeraddr=[fc57:be98:b90c:89a2:6807:69a0:827:947e]:43692 | > | 16:02:30.970 | Main 4 | GETDATA | 6312471 | | 2026-03-23T16:02:30.970148Z [msghand] [../../src/net\_processing.cpp:2876] [HeadersDirectFetchBlocks] [net] Requesting block 0000000000000000000085ebdcd669c404195dbfeccbee902fc646dadc367a20 from peer=6312471 | > | 16:02:31.324 | Main 4 | CMPCTBLOCK | 1283269 | | 2026-03-23T16:02:31.323094Z [msghand] [../../src/net\_processing.cpp:3575] [ProcessMessage] [net] received: cmpctblock (24495 bytes) peer=1283269 \n 2026-03-23T16:02:31.323969Z [msghand] [../../src/blockencodings.cpp:61] [InitData] [cmpctblock] Initializing PartiallyDownloadedBlock for block 0000000000000000000085ebdcd669c404195dbfeccbee902fc646dadc367a20 using a cmpctblock of 24495 bytes | > | 16:02:31.342 | Main 4 | GETBLOCKTXN | | 1283269 | 2026-03-23T16:02:31.341592Z [msghand] [../../src/net.cpp:4078] [PushMessage] [net] sending getblocktxn (773 bytes) peer=1283269 | > | 16:02:32.049 | Main 4 | BLOCKTXN | 1283269 | | 2026-03-23T16:02:32.028760Z [msghand] [../../src/net\_processing.cpp:3575] [ProcessMessage] [net] received: blocktxn (267997 bytes) peer=1283269 | > | 16:02:32.049 | Main 4 | CMPCTBLOCK Reconstructed | | | 2026-03-23T16:02:32.049006Z [msghand] [../../src/blockencodings.cpp:228] [FillBlock] [cmpctblock] Successfully reconstructed block 0000000000000000000085ebdcd669c404195dbfeccbee902fc646dadc367a20 with 1 txn prefilled, 3268 txn from mempool (incl at least 76 from extra pool) and 736 txn (267962 bytes) requested | > | 16:04:49.393 | Main 5 | INV | 199 | | 2026-03-23T16:04:49.393196Z [msghand] [../../src/net\_processing.cpp:4146] [ProcessMessage] [net] got inv: block 00000000000000000001f8562235e11fc74d5eea589e4c37b671b4213e89f52f new peer=199 | > | 16:04:49.393 | Main 5 | GETHEADERS | | 199 | 2026-03-23T16:04:49.393406Z [msghand] [../../src/net\_processing.cpp:4190] [ProcessMessage] [net] getheaders (941884) 00000000000000000001f8562235e11fc74d5eea589e4c37b671b4213e89f52f to peer=199 | > | 16:04:49.595 | Main 5 | HEADERS | 4392345 | | 2026-03-23T16:04:49.594756Z [msghand] [../../src/net\_processing.cpp:3546] [LogBlockHeader] Saw new header hash=00000000000000000001f8562235e11fc74d5eea589e4c37b671b4213e89f52f height=941885 peer=4392345, peeraddr=10.30.1.77:55010 | > | 16:04:49.595 | Main 5 | GETDATA | | 4392345 | 2026-03-23T16:04:49.594846Z [msghand] [../../src/net\_processing.cpp:2876] [HeadersDirectFetchBlocks] [net] Requesting block 00000000000000000001f8562235e11fc74d5eea589e4c37b671b4213e89f52f from peer=4392345 | > | 16:04:50.220 | Main 5 | BLOCK | | 4392345 | 2026-03-23T16:04:50.219701Z [msghand] [../../src/net\_processing.cpp:4859] [ProcessMessage] [net] received block 00000000000000000001f8562235e11fc74d5eea589e4c37b671b4213e89f52f peer=4392345 | > | 16:05:01.590 | Foundry 1 | Block stall timeout, disconnect peer | 199 | | 2026-03-23T16:05:01.590359Z [msghand] [../../src/net\_processing.cpp:6110] [SendMessages] Timeout downloading block 00000000000000000000bd4930a5982911e7749eb491886206e71abdc1ec0cc6, disconnecting peer=199, peeraddr=80.251.125.221:46532 | > | 16:05:01.612 | Foundry 1 | GETDATA | | 8302907 | 2026-03-23T16:05:01.611937Z [msghand] [../../src/net\_processing.cpp:6181] [SendMessages] [net] Requesting block 00000000000000000000bd4930a5982911e7749eb491886206e71abdc1ec0cc6 (941881) peer=8302907 | > | 16:05:01.612 | Foundry 2 | GETDATA | | 8302907 | 2026-03-23T16:05:01.611964Z [msghand] [../../src/net\_processing.cpp:6181] [SendMessages] [net] Requesting block 00000000000000000000724eac69a18c6699c9f7aaab24bcf18beb2723ccadd2 (941882) peer=8302907 | > | 16:05:02.593 | Foundry 1 | BLOCK | 8302907 | | 2026-03-23T16:05:02.592967Z [msghand] [../../src/net\_processing.cpp:4859] [ProcessMessage] [net] received block 00000000000000000000bd4930a5982911e7749eb491886206e71abdc1ec0cc6 peer=8302907 | > | 16:05:03.322 | Foundry 2 | BLOCK | 8302907 | | 2026-03-23T16:05:03.321989Z [msghand] [../../src/net\_processing.cpp:4859] [ProcessMessage] [net] received block 00000000000000000000724eac69a18c6699c9f7aaab24bcf18beb2723ccadd2 peer=8302907 | > | 16:05:03.434 | Antpool 2 | Block Disconnected | | | 2026-03-23T16:05:03.433595Z [scheduler] [../../src/validationinterface.cpp:239] [operator()] [validation] BlockDisconnected: block hash=00000000000000000000c81cbf94a12ca498e72eb8530f7061c8746cf9687b2e block height=941882 | > | 16:05:03.844 | Foundry 1 | Update Tip | | | 2026-03-23T16:05:03.843581Z [msghand] [../../src/validation.cpp:2867] [UpdateTipLog] UpdateTip: new best=00000000000000000000bd4930a5982911e7749eb491886206e71abdc1ec0cc6 height=941881 version=0x22cd4000 log2\_work=96.137382 tx=1327000861 date=‘2026-03-23T15:49:47Z’ progress=0.999990 cache=219.0MiB(1599154txo) | > | 16:05:04.065 | Foundry 2 | Update Tip | | | 2026-03-23T16:05:04.065420Z [msghand] [../../src/validation.cpp:2867] [UpdateTipLog] UpdateTip: new best=00000000000000000000724eac69a18c6699c9f7aaab24bcf18beb2723ccadd2 height=941882 version=0x3427e000 log2\_work=96.137391 tx=1327005400 date=‘2026-03-23T15:51:25Z’ progress=0.999993 cache=219.3MiB(1602981txo) | > | 16:05:04.355 | Foundry 3 | Update Tip | | | 2026-03-23T16:05:04.355114Z [msghand] [../../src/validation.cpp:2867] [UpdateTipLog] UpdateTip: new best=000000000000000000009c9acd0bc3207fa181f79f8573bf27d8a81d1ef3aa8e height=941883 version=0x2fc2e000 log2\_work=96.137401 tx=1327009788 date=‘2026-03-23T15:54:49Z’ progress=0.999995 cache=219.8MiB(1607191txo) | > | 16:05:04.425 | Antpool 1 | Block Disconnected | | | 2026-03-23T16:05:04.424781Z [scheduler] [../../src/validationinterface.cpp:239] [operator()] [validation] BlockDisconnected: block hash=00000000000000000001b3ff8b13e57c3ec1eca3ba7d2937edbd9f219eb2d9f3 block height=941881 | > | 16:05:08.862 | Main 4 | Update Tip | | | 2026-03-23T16:05:08.862000Z [msghand] [../../src/validation.cpp:2867] [UpdateTipLog] UpdateTip: new best=0000000000000000000085ebdcd669c404195dbfeccbee902fc646dadc367a20 height=941884 version=0x212b4000 log2\_work=96.137410 tx=1327013793 date=‘2026-03-23T16:02:14Z’ progress=0.999998 cache=220.3MiB(1610860txo) | > | 16:05:09.152 | Main 5 | Update Tip | | | 2026-03-23T16:05:09.152296Z [msghand] [../../src/validation.cpp:2867] [UpdateTipLog] UpdateTip: new best=00000000000000000001f8562235e11fc74d5eea589e4c37b671b4213e89f52f height=941885 version=0x22abe000 log2\_work=96.137420 tx=1327018030 date=‘2026-03-23T16:04:46Z’ progress=1.000000 cache=220.8MiB(1614193txo) | To kind of summarize what happened here, peer 199 (who aggressively `INV`’s blocks to this node and is often the first to do so) sent an INV of foundry’s first block, then this node sent a `GETHEADERS` then peer 199 replied with `HEADERS`, then the node sent a `GETDATA` for the block and peer 199 did not respond, notably the block stall time out is 10 minutes, and Bitcoin Core will not request a block while there is a block in-flight from a peer, the only escape valve during this stalling period is _if_ one of a node’s high-bandwidth compact block peers sends an unrequested block, but this node was unlucky enough to have all of its compact block HB peers end up on one side of the race. I suspect @b10c’s owen and greg were similarly stalled. This was also pointed out on [IRC](https://bitcoin-irc.chaincode.com/bitcoin-core-dev/2026-03-25#1774470438-1774471515;) to be related to [bitcoin/bitcoin#33687](https://github.com/bitcoin/bitcoin/issues/33687). The full log is available here if anyone else would like to analyze: [https://achow101.com/files/debug.log2026-03-23-foundry-reorg.txt](https://achow101.com/files/debug.log2026-03-23-foundry-reorg.txt) I mostly built the table by hand using grep and bubblegum, but I pasted it into gemini-3.1 and asked it to write a script to generate such tables from debug.log files and (with a few tweaks) it seems (at a glance) to mostly work with a few small hiccups, if others want to automate making similar tables: > **Fork timeline slop script** > > ```bash > python geminiscript.py debug.log blocks.conf > out.csv > > ``` > > ```auto > # blocks.conf > > # Format: HASH:LABEL > > 00000000000000000001b3ff8b13e57c3ec1eca3ba7d2937edbd9f219eb2d9f3:Antpool1 > 00000000000000000000c81cbf94a12ca498e72eb8530f7061c8746cf9687b2e:Antpool2 > > 00000000000000000000bd4930a5982911e7749eb491886206e71abdc1ec0cc6:Foundry1 > 00000000000000000000724eac69a18c6699c9f7aaab24bcf18beb2723ccadd2:Foundry2 > 000000000000000000009c9acd0bc3207fa181f79f8573bf27d8a81d1ef3aa8e:Foundry3 > > 0000000000000000000085ebdcd669c404195dbfeccbee902fc646dadc367a20:Main4 > 00000000000000000001f8562235e11fc74d5eea589e4c37b671b4213e89f52f:Main5 > > ``` > > ```python > # geminiscript.py > > import sys > import re > import argparse > > def load_block_config(config_path): > """Load block hashes and labels from a simple config file. > > Format (one per line): > HASH:LABEL > > Blank lines and lines starting with # are ignored. > """ > block_labels = {} > try: > with open(config_path, 'r') as f: > for lineno, line in enumerate(f, 1): > line = line.strip() > if not line or line.startswith('#'): > continue > if ':' not in line: > print( > f"Error: {config_path}:{lineno}: expected HASH:LABEL format, got '{line}'", > file=sys.stderr, > ) > sys.exit(1) > b_hash, b_label = line.split(':', 1) > block_labels[b_hash.strip()] = b_label.strip() > except FileNotFoundError: > print(f"Error: Could not find config file {config_path}", file=sys.stderr) > sys.exit(1) > > if not block_labels: > print(f"Error: No block entries found in {config_path}", file=sys.stderr) > sys.exit(1) > > return block_labels > > def main(): > parser = argparse.ArgumentParser( > description="High-performance Bitcoin debug.log block race analyzer." > ) > parser.add_argument("log_file", help="Path to the debug.log file") > parser.add_argument( > "blocks_file", > help="Path to a blocks config file (one HASH:LABEL per line)", > ) > args = parser.parse_args() > > block_labels = load_block_config(args.blocks_file) > > # Regex for extracting timestamps accurately > time_rx = re.compile(r'^.*?(\d{4}-\d{2}-\d{2}[T](\d{2}:\d{2}:\d{2}(?:\.\d+)?))') > > # Define all event patterns. > # Tuple: (Regex, Event Name, Direction of Peer (From/To)) > action_patterns = [ > (re.compile(r'got inv: block (?P[a-f0-9]{64}).*peer=(?P\d+)'), 'INV', 'From'), > (re.compile(r'getheaders \(\d+\) (?P[a-f0-9]{64}) to peer=(?P\d+)'), 'GETHEADERS', 'To'), > (re.compile(r'(?:Saw new header hash=|Saw new cmpctblock header hash=)(?P[a-f0-9]{64}).*peer=(?P\d+)'), 'HEADERS', 'From'), > (re.compile(r'Requesting block (?P[a-f0-9]{64}).*peer=(?P\d+)'), 'GETDATA', 'To'), > (re.compile(r'received block (?P[a-f0-9]{64}).*peer=(?P\d+)'), 'BLOCK', 'From'), > (re.compile(r'Successfully reconstructed block (?P[a-f0-9]{64})'), 'CMPCTBLOCK Reconstructed', 'From'), > (re.compile(r'UpdateTip: new best=(?P[a-f0-9]{64})'), 'Update Tip', ''), > (re.compile(r'Timeout downloading block (?P[a-f0-9]{64}), disconnecting peer=(?P\d+)'), 'Block stall timeout: disconnect peer', 'From'), > (re.compile(r'BlockDisconnected: block hash=(?P[a-f0-9]{64})'), 'Block Disconnected', ''), > > # Multi-line / State machine triggers > (re.compile(r'received: cmpctblock .* peer=(?P\d+)'), 'RX_CMPCTBLOCK', ''), > (re.compile(r'Initializing PartiallyDownloadedBlock for block (?P[a-f0-9]{64})'), 'INIT_PDB', ''), > (re.compile(r'Initialized PartiallyDownloadedBlock for block (?P[a-f0-9]{64})'), 'INITED_PDB', ''), > (re.compile(r'sending getblocktxn .* peer=(?P\d+)'), 'TX_GETBLOCKTXN', ''), > (re.compile(r'received: blocktxn .* peer=(?P\d+)'), 'RX_BLOCKTXN', ''), > ] > > # FAST PATH EXCLUSION > fast_keywords = list(block_labels.keys()) + ['cmpctblock', 'getblocktxn', 'blocktxn'] > fast_filter = re.compile('|'.join(map(re.escape, fast_keywords))) > > # State tracking dictionaries > peer_for_hash = {} > hash_for_peer = {} > pending_cmpctblock = None > pending_getblocktxn = None > > print("Time,Block,Msg/Action,From Peer,To Peer,Log message") > > try: > with open(args.log_file, 'r', encoding='utf-8', errors='ignore') as f: > for line in f: > if not fast_filter.search(line): > continue > > t_match = time_rx.search(line) > if not t_match: > continue > time_val = t_match.group(2) > > for rx, action, direction in action_patterns: > m = rx.search(line) > if m: > gd = m.groupdict() > h = gd.get('hash') > p = gd.get('peer') > > if action == 'RX_CMPCTBLOCK': > pending_cmpctblock = (p, line.strip()) > break > elif action == 'INIT_PDB': > if h in block_labels and pending_cmpctblock: > p_peer, p_line = pending_cmpctblock > combined_line = f"{p_line} \\n {line.strip()}" > peer_for_hash[h] = p_peer > hash_for_peer[p_peer] = h > print(f"{time_val},{block_labels[h]},CMPCTBLOCK,{p_peer},,\"{combined_line}\"") > pending_cmpctblock = None > break > elif action == 'INITED_PDB': > if h in block_labels: > pending_getblocktxn = (h, line.strip()) > break > elif action == 'TX_GETBLOCKTXN': > if pending_getblocktxn: > p_hash, p_line = pending_getblocktxn > if p_hash in block_labels: > combined_line = f"{p_line} \\n {line.strip()}" > peer_for_hash[p_hash] = p > hash_for_peer[p] = p_hash > print(f"{time_val},{block_labels[p_hash]},GETBLOCKTXN,,{p},\"{combined_line}\"") > pending_getblocktxn = None > break > elif action == 'RX_BLOCKTXN': > target_hash = hash_for_peer.get(p) > if target_hash and target_hash in block_labels: > print(f"{time_val},{block_labels[target_hash]},BLOCKTXN,{p},,\"{line.strip()}\"") > break > > if h: > if h not in block_labels: > break > label = block_labels[h] > if p: > peer_for_hash[h] = p > hash_for_peer[p] = h > else: > p = peer_for_hash.get(h, '') > from_p = p if direction == 'From' else '' > to_p = p if direction == 'To' else '' > print(f"{time_val},{label},{action},{from_p},{to_p},\"{line.strip()}\"") > > break > > except KeyboardInterrupt: > print("\nProcess interrupted by user.", file=sys.stderr) > except FileNotFoundError: > print(f"Error: Could not find file {args.log_file}", file=sys.stderr) > > if __name__ == " __main__": > main() > > ``` > > **Edit:** I have updated this script with a fix for it logging duplicate update tips and grabbing extra `BLOCKTXN` messages from the end of logs. ---
### Author: ![b10c](https://bnoc.xyz/user_avatar/bnoc.xyz/b10c/32/4_2.png) [@b10c](https://bnoc.xyz/u/b10c) #### Post date: [March 26, 2026, 8:16am UTC](https://bnoc.xyz/t/two-block-reorg-at-height-941880/97/20 "2026-03-26T08:16:31Z")
A miner mining on Foundry shared the following stratum job data with me. I’ve anonymized it a bit. | first job arrival timestamp | mining on block | duration on this tip | | --- | --- | --- | | 15:48:16.700 | 941880 Foundry | ~ 98s | | 15:49:54.200 | 941881 AntPool (stale) | ~ 1s | | 15:49:55.300 | 941881 Foundry | ~ 112s | | 15:51:47.350 | 941882 ViaBTC (stale) | ~ 1.3s | | 15:51:48.700 | 941882 Foundry | ~ 192s | | 15:55:00.500 | 941883 Foundry | \> 5min | * * * My takeaway from this is: - at 15.49:54, Foundry send a job building on top of the AntPool 941881 block, but switched to it’s Foundry 941881 block around 1s later - then, at 15:51:47, ViaBTC found a block at height 941882, Foundry switched to this block, but after 1.3s switched to Foundry’s 941882 * * * Foundry switching to their own block (e.g. with `preciousblock`) is a very reasonable thing to do for them. We know Foundry has been doing this for a while, and AntPool, for whatever reason, does not: [Mining Pool Behavior during Forks](https://b10c.me/blog/014-mining-pool-behavior-during-forks/) This also shows that Foundry too saw the AntPool and ViaBTC blocks arriving first. However, it’s not unreasonable that a miner submitted a valid share even after the AntPool & ViaBTC blocks where known to the network. See e.g. [AntPool mines two blocks at height 925051](https://bnoc.xyz/t/antpool-mines-two-blocks-at-height-925051/60) where AntPool miners found two valid shares at a similar time. ---
### Author: ![zawy12](https://bnoc.xyz/user_avatar/bnoc.xyz/zawy12/32/155_2.png) [@zawy12](https://bnoc.xyz/u/zawy12) #### Post date: [March 26, 2026, 3:09pm UTC](https://bnoc.xyz/t/two-block-reorg-at-height-941880/97/21 "2026-03-26T15:09:19Z")
In a sample 2 years ago, all the pools seemed to be time-rolling because timestamps of all the pools seemed to average ~20 seconds before the header arrived and had a 20 s stdev. 5% of blocks had a stamp in the future. 0.4% had a block \> 60 s in the past. Brainspool was an exception averaging 11 seconds with stdev of 25 (they a lot of blocks with timestamps in the future). ---
### Author: ![b10c](https://bnoc.xyz/user_avatar/bnoc.xyz/b10c/32/4_2.png) [@b10c](https://bnoc.xyz/u/b10c) #### Post date: [March 26, 2026, 6:00pm UTC](https://bnoc.xyz/t/two-block-reorg-at-height-941880/97/22 "2026-03-26T18:00:52Z")
I raw two of my nodes logs through @davidgumberg’s script. `owen`, a node that got stalled (by the same peer; see `Block stall timeout: disconnect peer`) and did only receive the 941881 Foundry block at around 16:05: > **owen** > > | Time | Block | Msg/Action | From Peer | To Peer | Log message | > | --- | --- | --- | --- | --- | --- | > | 15:49:53.833781 | Antpool1 | INV | 140374 | | 2026-03-23T15:49:53.833781Z [msghand] [net] got inv: block 00000000000000000001b3ff8b13e57c3ec1eca3ba7d2937edbd9f219eb2d9f3 new peer=140374 | > | 15:49:53.834143 | Antpool1 | GETHEADERS | | 140374 | 2026-03-23T15:49:53.834143Z [msghand] [net] getheaders (941880) 00000000000000000001b3ff8b13e57c3ec1eca3ba7d2937edbd9f219eb2d9f3 to peer=140374 | > | 15:49:54.029989 | Antpool1 | HEADERS | 127889 | | 2026-03-23T15:49:54.029989Z [msghand] Saw new cmpctblock header hash=00000000000000000001b3ff8b13e57c3ec1eca3ba7d2937edbd9f219eb2d9f3 height=941881 peer=127889 peeraddr=X | > | 15:49:54.030397 | Antpool1 | CMPCTBLOCK | 127889 | | 2026-03-23T15:49:54.028551Z [msghand] [net] received: cmpctblock (27910 bytes) peer=127889 \n 2026-03-23T15:49:54.030397Z [msghand] [cmpctblock] Initializing PartiallyDownloadedBlock for block 00000000000000000001b3ff8b13e57c3ec1eca3ba7d2937edbd9f219eb2d9f3 using a cmpctblock of 27910 bytes | > | 15:49:54.056084 | Antpool1 | GETBLOCKTXN | | 127889 | 2026-03-23T15:49:54.055526Z [msghand] [cmpctblock] Initialized PartiallyDownloadedBlock for block 00000000000000000001b3ff8b13e57c3ec1eca3ba7d2937edbd9f219eb2d9f3 using a cmpctblock of 27910 bytes \n 2026-03-23T15:49:54.056084Z [msghand] [net] sending getblocktxn (93 bytes) peer=127889 | > | 15:49:54.123920 | Antpool1 | BLOCKTXN | 127889 | | 2026-03-23T15:49:54.123920Z [msghand] [net] received: blocktxn (21507 bytes) peer=127889 | > | 15:49:54.133473 | Antpool1 | CMPCTBLOCK Reconstructed | 127889 | | 2026-03-23T15:49:54.133473Z [msghand] [cmpctblock] Successfully reconstructed block 00000000000000000001b3ff8b13e57c3ec1eca3ba7d2937edbd9f219eb2d9f3 with 1 txn prefilled, 4510 txn from mempool (incl at least 0 from extra pool) and 56 txn (21474 bytes) requested | > | 15:49:54.585760 | Antpool1 | Update Tip | | | 2026-03-23T15:49:54.585760Z [msghand] UpdateTip: new best=00000000000000000001b3ff8b13e57c3ec1eca3ba7d2937edbd9f219eb2d9f3 height=941881 version=0x3092c000 log2\_work=96.137382 tx=1327000957 date=‘2026-03-23T15:49:35Z’ progress=1.000000 cache=582.2MiB(4357927txo) | > | 15:49:54.585931 | Antpool1 | UpdateTip | 127889 | | 2026-03-23T15:49:54.585931Z [msghand] [validation] Enqueuing UpdatedBlockTip: new block hash=00000000000000000001b3ff8b13e57c3ec1eca3ba7d2937edbd9f219eb2d9f3 fork block hash=0000000000000000000199a739b635c5707a2bda57231b8abe846216ca0cc989 (in IBD=false) | > | 15:50:01.254651 | Foundry1 | INV | 140374 | | 2026-03-23T15:50:01.254651Z [msghand] [net] got inv: block 00000000000000000000bd4930a5982911e7749eb491886206e71abdc1ec0cc6 new peer=140374 | > | 15:50:01.254993 | Foundry1 | GETHEADERS | | 140374 | 2026-03-23T15:50:01.254993Z [msghand] [net] getheaders (941881) 00000000000000000000bd4930a5982911e7749eb491886206e71abdc1ec0cc6 to peer=140374 | > | 15:51:47.118183 | Antpool2 | HEADERS | 42523 | | 2026-03-23T15:51:47.118183Z [msghand] Saw new header hash=00000000000000000000c81cbf94a12ca498e72eb8530f7061c8746cf9687b2e height=941882 peer=42523 peeraddr=X | > | 15:51:47.118237 | Antpool2 | GETDATA | | 42523 | 2026-03-23T15:51:47.118237Z [msghand] [net] Requesting block 00000000000000000000c81cbf94a12ca498e72eb8530f7061c8746cf9687b2e from peer=42523 | > | 15:51:47.134567 | Antpool2 | CMPCTBLOCK | 59642 | | 2026-03-23T15:51:47.134077Z [msghand] [net] received: cmpctblock (5773 bytes) peer=59642 \n 2026-03-23T15:51:47.134567Z [msghand] [cmpctblock] Initializing PartiallyDownloadedBlock for block 00000000000000000000c81cbf94a12ca498e72eb8530f7061c8746cf9687b2e using a cmpctblock of 5773 bytes | > | 15:51:47.152286 | Antpool2 | CMPCTBLOCK Reconstructed | 59642 | | 2026-03-23T15:51:47.152286Z [msghand] [cmpctblock] Successfully reconstructed block 00000000000000000000c81cbf94a12ca498e72eb8530f7061c8746cf9687b2e with 1 txn prefilled, 871 txn from mempool (incl at least 1 from extra pool) and 0 txn (0 bytes) requested | > | 15:51:47.301996 | Antpool2 | Update Tip | | | 2026-03-23T15:51:47.301996Z [msghand] UpdateTip: new best=00000000000000000000c81cbf94a12ca498e72eb8530f7061c8746cf9687b2e height=941882 version=0x2008c000 log2\_work=96.137391 tx=1327001829 date=‘2026-03-23T15:51:19Z’ progress=1.000000 cache=582.2MiB(4358945txo) | > | 15:51:47.302133 | Antpool2 | UpdateTip | 59642 | | 2026-03-23T15:51:47.302133Z [msghand] [validation] Enqueuing UpdatedBlockTip: new block hash=00000000000000000000c81cbf94a12ca498e72eb8530f7061c8746cf9687b2e fork block hash=00000000000000000001b3ff8b13e57c3ec1eca3ba7d2937edbd9f219eb2d9f3 (in IBD=false) | > | 15:51:47.400435 | Antpool2 | INV | 140374 | | 2026-03-23T15:51:47.400435Z [msghand] [net] got inv: block 00000000000000000000c81cbf94a12ca498e72eb8530f7061c8746cf9687b2e have peer=140374 | > | 15:55:01.141852 | Foundry2 | INV | 140374 | | 2026-03-23T15:55:01.141852Z [msghand] [net] got inv: block 00000000000000000000724eac69a18c6699c9f7aaab24bcf18beb2723ccadd2 new peer=140374 | > | 15:55:01.142559 | Foundry2 | GETHEADERS | | 140374 | 2026-03-23T15:55:01.142559Z [msghand] [net] getheaders (941882) 00000000000000000000724eac69a18c6699c9f7aaab24bcf18beb2723ccadd2 to peer=140374 | > | 15:55:01.283400 | Foundry3 | INV | 140374 | | 2026-03-23T15:55:01.283400Z [msghand] [net] got inv: block 000000000000000000009c9acd0bc3207fa181f79f8573bf27d8a81d1ef3aa8e new peer=140374 | > | 15:55:01.429284 | Foundry2 | HEADERS | 140374 | | 2026-03-23T15:55:01.429284Z [msghand] Saw new header hash=00000000000000000000724eac69a18c6699c9f7aaab24bcf18beb2723ccadd2 height=941882 peer=140374 peeraddr=80.251.125.221:35626 | > | 15:55:01.429341 | Foundry1 | GETDATA | | 140374 | 2026-03-23T15:55:01.429341Z [msghand] [net] Requesting block 00000000000000000000bd4930a5982911e7749eb491886206e71abdc1ec0cc6 from peer=140374 | > | 15:55:01.429362 | Foundry2 | GETDATA | | 140374 | 2026-03-23T15:55:01.429362Z [msghand] [net] Requesting block 00000000000000000000724eac69a18c6699c9f7aaab24bcf18beb2723ccadd2 from peer=140374 | > | 15:55:01.780852 | Foundry3 | HEADERS | 214021 | | 2026-03-23T15:55:01.780852Z [msghand] Saw new header hash=000000000000000000009c9acd0bc3207fa181f79f8573bf27d8a81d1ef3aa8e height=941883 peer=214021 peeraddr=X | > | 15:55:01.780957 | Foundry3 | GETDATA | | 214021 | 2026-03-23T15:55:01.780957Z [msghand] [net] Requesting block 000000000000000000009c9acd0bc3207fa181f79f8573bf27d8a81d1ef3aa8e from peer=214021 | > | 15:55:03.491469 | Foundry3 | BLOCK | 214021 | | 2026-03-23T15:55:03.491469Z [msghand] [net] received block 000000000000000000009c9acd0bc3207fa181f79f8573bf27d8a81d1ef3aa8e peer=214021 | > | 16:02:30.896711 | Main4 | INV | 140374 | | 2026-03-23T16:02:30.896711Z [msghand] [net] got inv: block 0000000000000000000085ebdcd669c404195dbfeccbee902fc646dadc367a20 new peer=140374 | > | 16:02:30.897048 | Main4 | GETHEADERS | | 140374 | 2026-03-23T16:02:30.897048Z [msghand] [net] getheaders (941883) 0000000000000000000085ebdcd669c404195dbfeccbee902fc646dadc367a20 to peer=140374 | > | 16:02:30.993875 | Main4 | HEADERS | 200279 | | 2026-03-23T16:02:30.993875Z [msghand] Saw new header hash=0000000000000000000085ebdcd669c404195dbfeccbee902fc646dadc367a20 height=941884 peer=200279 peeraddr=X | > | 16:02:30.993958 | Main4 | GETDATA | | 200279 | 2026-03-23T16:02:30.993958Z [msghand] [net] Requesting block 0000000000000000000085ebdcd669c404195dbfeccbee902fc646dadc367a20 from peer=200279 | > | 16:02:31.038904 | Main4 | CMPCTBLOCK | 127889 | | 2026-03-23T16:02:31.037396Z [msghand] [net] received: cmpctblock (24495 bytes) peer=127889 \n 2026-03-23T16:02:31.038904Z [msghand] [cmpctblock] Initializing PartiallyDownloadedBlock for block 0000000000000000000085ebdcd669c404195dbfeccbee902fc646dadc367a20 using a cmpctblock of 24495 bytes | > | 16:02:31.063406 | Main4 | GETBLOCKTXN | | 127889 | 2026-03-23T16:02:31.062281Z [msghand] [cmpctblock] Initialized PartiallyDownloadedBlock for block 0000000000000000000085ebdcd669c404195dbfeccbee902fc646dadc367a20 using a cmpctblock of 24495 bytes \n 2026-03-23T16:02:31.063406Z [msghand] [net] sending getblocktxn (769 bytes) peer=127889 | > | 16:02:31.190960 | Main4 | BLOCKTXN | 127889 | | 2026-03-23T16:02:31.190960Z [msghand] [net] received: blocktxn (267101 bytes) peer=127889 | > | 16:02:31.216282 | Main4 | CMPCTBLOCK Reconstructed | 127889 | | 2026-03-23T16:02:31.216282Z [msghand] [cmpctblock] Successfully reconstructed block 0000000000000000000085ebdcd669c404195dbfeccbee902fc646dadc367a20 with 1 txn prefilled, 3272 txn from mempool (incl at least 80 from extra pool) and 732 txn (267066 bytes) requested | > | 16:02:35.325659 | Main4 | BLOCK | 200279 | | 2026-03-23T16:02:35.325659Z [msghand] [net] received block 0000000000000000000085ebdcd669c404195dbfeccbee902fc646dadc367a20 peer=200279 | > | 16:04:49.362087 | Main5 | HEADERS | 127889 | | 2026-03-23T16:04:49.362087Z [msghand] Saw new cmpctblock header hash=00000000000000000001f8562235e11fc74d5eea589e4c37b671b4213e89f52f height=941885 peer=127889 peeraddr=X | > | 16:04:49.362198 | Main5 | GETDATA | | 127889 | 2026-03-23T16:04:49.362198Z [msghand] [net] Requesting block 00000000000000000001f8562235e11fc74d5eea589e4c37b671b4213e89f52f from peer=127889 | > | 16:04:49.376749 | Main5 | INV | 140374 | | 2026-03-23T16:04:49.376749Z [msghand] [net] got inv: block 00000000000000000001f8562235e11fc74d5eea589e4c37b671b4213e89f52f have peer=140374 | > | 16:04:50.082036 | Main5 | BLOCK | 127889 | | 2026-03-23T16:04:50.082036Z [msghand] [net] received block 00000000000000000001f8562235e11fc74d5eea589e4c37b671b4213e89f52f peer=127889 | > | 16:04:55.059965 | Main5 | INV | 215836 | | 2026-03-23T16:04:55.059965Z [msghand] [net] got inv: block 00000000000000000001f8562235e11fc74d5eea589e4c37b671b4213e89f52f have peer=215836 | > | 16:05:01.441346 | Foundry1 | Block stall timeout: disconnect peer | 140374 | | 2026-03-23T16:05:01.441346Z [msghand] Timeout downloading block 00000000000000000000bd4930a5982911e7749eb491886206e71abdc1ec0cc6, disconnecting peer=140374 peeraddr=80.251.125.221:35626 | > | 16:05:01.474666 | Foundry1 | GETDATA | | 147259 | 2026-03-23T16:05:01.474666Z [msghand] [net] Requesting block 00000000000000000000bd4930a5982911e7749eb491886206e71abdc1ec0cc6 (941881) peer=147259 | > | 16:05:01.474694 | Foundry2 | GETDATA | | 147259 | 2026-03-23T16:05:01.474694Z [msghand] [net] Requesting block 00000000000000000000724eac69a18c6699c9f7aaab24bcf18beb2723ccadd2 (941882) peer=147259 | > | 16:05:03.395825 | Foundry1 | BLOCK | 147259 | | 2026-03-23T16:05:03.395825Z [msghand] [net] received block 00000000000000000000bd4930a5982911e7749eb491886206e71abdc1ec0cc6 peer=147259 | > | 16:05:04.384588 | Foundry2 | BLOCK | 147259 | | 2026-03-23T16:05:04.384588Z [msghand] [net] received block 00000000000000000000724eac69a18c6699c9f7aaab24bcf18beb2723ccadd2 peer=147259 | > | 16:05:04.668570 | Antpool1 | Update Tip | | | 2026-03-23T16:05:04.668570Z [msghand] UpdateTip: new best=00000000000000000001b3ff8b13e57c3ec1eca3ba7d2937edbd9f219eb2d9f3 height=941881 version=0x3092c000 log2\_work=96.137382 tx=1327000957 date=‘2026-03-23T15:49:35Z’ progress=0.999990 cache=582.2MiB(4358698txo) | > | 16:05:04.668604 | Antpool2 | Block Disconnected | | | 2026-03-23T16:05:04.668604Z [msghand] [validation] Enqueuing BlockDisconnected: block hash=00000000000000000000c81cbf94a12ca498e72eb8530f7061c8746cf9687b2e block height=941882 | > | 16:05:04.668778 | Antpool2 | Block Disconnected | | | 2026-03-23T16:05:04.668778Z [scheduler] [validation] BlockDisconnected: block hash=00000000000000000000c81cbf94a12ca498e72eb8530f7061c8746cf9687b2e block height=941882 | > | 16:05:05.084714 | Antpool1 | Block Disconnected | | | 2026-03-23T16:05:05.084714Z [msghand] [validation] Enqueuing BlockDisconnected: block hash=00000000000000000001b3ff8b13e57c3ec1eca3ba7d2937edbd9f219eb2d9f3 block height=941881 | > | 16:05:05.084967 | Antpool1 | Block Disconnected | | | 2026-03-23T16:05:05.084967Z [scheduler] [validation] BlockDisconnected: block hash=00000000000000000001b3ff8b13e57c3ec1eca3ba7d2937edbd9f219eb2d9f3 block height=941881 | > | 16:05:05.405137 | Foundry1 | Update Tip | | | 2026-03-23T16:05:05.405137Z [msghand] UpdateTip: new best=00000000000000000000bd4930a5982911e7749eb491886206e71abdc1ec0cc6 height=941881 version=0x22cd4000 log2\_work=96.137382 tx=1327000861 date=‘2026-03-23T15:49:47Z’ progress=0.999990 cache=582.2MiB(4358725txo) | > | 16:05:05.810945 | Foundry2 | Update Tip | | | 2026-03-23T16:05:05.810945Z [msghand] UpdateTip: new best=00000000000000000000724eac69a18c6699c9f7aaab24bcf18beb2723ccadd2 height=941882 version=0x3427e000 log2\_work=96.137391 tx=1327005400 date=‘2026-03-23T15:51:25Z’ progress=0.999993 cache=582.7MiB(4362711txo) | > | 16:05:06.302796 | Foundry3 | Update Tip | | | 2026-03-23T16:05:06.302796Z [msghand] UpdateTip: new best=000000000000000000009c9acd0bc3207fa181f79f8573bf27d8a81d1ef3aa8e height=941883 version=0x2fc2e000 log2\_work=96.137401 tx=1327009788 date=‘2026-03-23T15:54:49Z’ progress=0.999995 cache=583.2MiB(4367114txo) | > | 16:05:06.365100 | Foundry3 | UpdateTip | 214021 | | 2026-03-23T16:05:06.365100Z [msghand] [validation] Enqueuing UpdatedBlockTip: new block hash=000000000000000000009c9acd0bc3207fa181f79f8573bf27d8a81d1ef3aa8e fork block hash=0000000000000000000199a739b635c5707a2bda57231b8abe846216ca0cc989 (in IBD=false) | > | 16:05:06.962855 | Main4 | Update Tip | | | 2026-03-23T16:05:06.962855Z [msghand] UpdateTip: new best=0000000000000000000085ebdcd669c404195dbfeccbee902fc646dadc367a20 height=941884 version=0x212b4000 log2\_work=96.137410 tx=1327013793 date=‘2026-03-23T16:02:14Z’ progress=0.999998 cache=583.7MiB(4371336txo) | > | 16:05:06.963006 | Main4 | UpdateTip | 200279 | | 2026-03-23T16:05:06.963006Z [msghand] [validation] Enqueuing UpdatedBlockTip: new block hash=0000000000000000000085ebdcd669c404195dbfeccbee902fc646dadc367a20 fork block hash=000000000000000000009c9acd0bc3207fa181f79f8573bf27d8a81d1ef3aa8e (in IBD=false) | > | 16:05:07.384763 | Main5 | Update Tip | | | 2026-03-23T16:05:07.384763Z [msghand] UpdateTip: new best=00000000000000000001f8562235e11fc74d5eea589e4c37b671b4213e89f52f height=941885 version=0x22abe000 log2\_work=96.137420 tx=1327018030 date=‘2026-03-23T16:04:46Z’ progress=1.000000 cache=584.2MiB(4374804txo) | > | 16:05:07.384908 | Main5 | UpdateTip | 215836 | | 2026-03-23T16:05:07.384908Z [msghand] [validation] Enqueuing UpdatedBlockTip: new block hash=00000000000000000001f8562235e11fc74d5eea589e4c37b671b4213e89f52f fork block hash=0000000000000000000085ebdcd669c404195dbfeccbee902fc646dadc367a20 (in IBD=false) | [Next page](https://bnoc.xyz/t/two-block-reorg-at-height-941880/97.md?page=2)