estimatesmartfee returns 50 sat/vB on an empty mempool for inclusion in 1008 blocks #26304

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Expected behavior

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when the mempool is empty, i expect something really low, at least smaller than 3 sat/vB, but not 50 sat/vB

Actual behavior

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$ bitcoin-cli -testnet estimatesmartfee 1
{
  "feerate": 0.00050106,
  "blocks": 2
}

$ bitcoin-cli -testnet estimatesmartfee 1008
{
  "feerate": 0.00050106,
  "blocks": 111
}

To reproduce

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run bitcoin-cli -testnet estimatesmartfee on the testnet when the difficulty drops to 1 (happens every few months or so i dont know why)

System information

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bitcoincore.org download v23

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Any extra information that might be useful in the debugging process.

blocks were flowing in like every few seconds a block got mined

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when the difficulty drops to 1 (happens every few months or so i dont know why)

See the fresh new #26303.

I don't think anything can be done here. Seems overkill to adjust estimatesmartfee to accommodate a broken test network. Have you tried signet?

Have you tried signet?

it works fine on the signet, empty mempool there and it almost always stays close to 1 sat/vB, just like the testnet when block speed is normal it just feels really counter-intuitive to get a high fee estimation when blocks are mined really fast and the mempool is empty

I don't think anything can be done here

This appears to be something that isn't going to be picked up in the near future.