Testnet difficulty was reset at height 2350655 #26303

1. 
   leevlad commented at 2:11 pm on October 13, 2022: none

   It appears that the testnet difficulty was reset from 83,269,806.51979084 at block height 2350654 down to 1.00 in the next block at height 2350655.

   I’m seeing this on my own testnet nodes (v23.0) as well as on several blockchain explorers (e.g. blockchain.com and blockchair)

   At the time of writing this post, the network has produced about 16k blocks in 6 hours, while the difficulty is crawling back up slowly (it’s at 65,536.00 at the time of writing).

   Was this a scheduled testnet reset of some kind or maybe a bug?

2. leevlad added the label Bug on Oct 13, 2022
3. 
   aureleoules commented at 2:27 pm on October 13, 2022: member

   if no block has been found in 20 minutes, the difficulty automatically resets back to the minimum for a single block

   from https://en.bitcoin.it/wiki/Testnet

   Block 2350654 was mined on Oct 13, 2022, 9:54:51 AM Block 2350655 was mined on Oct 13, 2022, 10:15:06 AM

4. 
   leevlad commented at 2:39 pm on October 13, 2022: none

   Thank you, I was unaware of this behavior on the Testnet.
5. leevlad closed this on Oct 13, 2022

   ---

6. leevlad reopened this on Oct 13, 2022

   ---

7. 
   leevlad commented at 2:45 pm on October 13, 2022: none

   After reading the above wiki link, I noticed the second part of the statement:

   if no block has been found in 20 minutes, the difficulty automatically resets back to the minimum for a single block, after which it returns to its previous value

   I don’t see the difficulty returning to its previous value in subsequent blocks. Is that an error in the wiki?

8. 
   sipa commented at 2:46 pm on October 13, 2022: member

   There is more happening here.

   When the testnet 20-minute rule triggers on a difficulty adjustment block, the rule acts as a permanent reset of the difficulty rather than a one-off.

   This was unintentional when the 20-minute rule was introduced, but now we’re effectively stuck with it (until testnet is replaced, of course).

9. 
   leevlad commented at 2:50 pm on October 13, 2022: none

   TIL. Thank you.
10. leevlad closed this on Oct 13, 2022

    ---

11. bitcoin locked this on Oct 13, 2023

Contributors
leevlad aureleoules sipa

Labels
Bug