#### Project Information
* Repository: https://github.com/steemit/steem
* Project Name: Steem

https://github.com/steemit/steem/issues/3184

#### Expected behavior
- SBD print rate should be 0% now.

I believe this bug itself must be well-known now, so this is mainly for explanation in detail, and more importantly, some suggestions. This is a very important issue, so it shouldn't be fixed by a temporary measure.

While I'm not sure this is intended or not, `get_feed_history()` shows `current_median_history` as the value already **discounted by the so-called haircut**. I think this is highly confusing and where all the mess begins. You shouldn't do that way.

##### Suggestions
- Use non-haircut value for ``current_median_history`` for consistency
  - All other real history values are non-haircut values, as you can see on https://api.steemjs.com/get_feed_history. This inconsistency can create lots of confusions, e.g., recent asset value error (steemit.com) / voting value error (busy.org which they still have)
  - Witnesses still need to report non-haircut prices, which again is very inconsistent and confusing. (https://steemd.com/witnesses)

- Introduce a new variable such as `"haircut discount"` and show the value on steemd and `get_feed_history` as well.
  - For instance, https://api.steemjs.com/get_feed_history should show "base": "0.328 SBD", "quote": "1.000 STEEM", "haircut": "0.796" 
  - This makes the code much more readable and much less prone to bugs such as the current one.

In reality, it might be already late to change the behavior of ``current_median_history`` in the code. Then introduce a new variable. In any case, UI (e.g., steemd.com) should show non-haircut value for the current feed price with haircut discount separately.

#### Actual behavior
SBD print rate is still 1%.

This bug is due to separate and inconsistent calculations for `current_median_history` and `sbd_print_rate`.

The `sbd_print_rate` is calculated here
https://github.com/steemit/steem/blob/7ebe3f8bddf9e58c943618f55136db6330dd95a0/libraries/chain/database.cpp#L3761-L3783

The first problem is `current_median_history` is already haircut (which I don't recommend doing so in Expected bahavior), so `percent_sbd` can never surpass 10%. 

The second problem is due to the inflation between the time when `current_median_history` is calculated and the time when `update_virtual_supply()` (which updates `sbd_print_rate`) is called, `percent_sbd` is always strictly less than 10% just a bit.

I explain this in more detail below.


#### High-level
> **update_median_feed()**;
> **update_virtual_supply()**;
>
> clear_null_account_balance();
**process_funds()**;
process_conversions();
process_comment_cashout();
process_vesting_withdrawals();
process_savings_withdraws();
process_subsidized_accounts();
pay_liquidity_reward();
**update_virtual_supply()**;

> https://github.com/steemit/steem/blob/7ebe3f8bddf9e58c943618f55136db6330dd95a0/libraries/chain/database.cpp#L3093-L3104

As you can see in the above, `update_virtual_supply()` (which updates `sbd_print_rate`) is called twice.

The problem is `update_median_feed()` limit the `current_median_history` so that `sbd_print_rate` at most 10% already.
```
price min_price( asset( 9 * gpo.current_sbd_supply.amount, SBD_SYMBOL ), gpo.current_supply );

if( min_price > fho.current_median_history )
   fho.current_median_history = min_price;
```
> https://github.com/steemit/steem/blob/7ebe3f8bddf9e58c943618f55136db6330dd95a0/libraries/chain/database.cpp#L3269-L3272

Unless you're very lucky due to floating point precision error, `sbd_print_rate` is already strictly less than 10% in the first call of `update_virtual_supply()`.

But even if you were very lucky,  now `process_funds()` inflates the supply.

(While there are other functions that change `virtual_supply` or `current_sbd_supply`, they don't change them in the direction of the `sbd_print_rate` increase. So let me skip too much details here.)

Thus, in the second `update_virtual_supply()`, sbd_print_rate is always strictly less than 10% regardless of your luck :)


#### How to reproduce
Don't need to explain, since it's always happening now.

#### Recording Of The Bug
![](https://ipfs.busy.org/ipfs/QmYnPcSiKX9KWi1DBFBJSnSqmrU4Gro2NQ9ieNwB4H9N7r) ![](https://ipfs.busy.org/ipfs/QmVTTC8nzCPFvMc3wBvUhXjCa1XYWsNXXWdMaV1khSzccG)
> steemd.com




#### GitHub Account
https://github.com/economicstudio