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IDProjectCategoryView StatusLast Update
0007937Talerwallet-corepublic2023-12-24 06:29
Reportersebasjm Assigned ToChristian Grothoff  
Status closedResolutionwon't fix 
Product Versiongit (master) 
Target Version0.9.4Fixed in Version0.9.4 
Summary0007937: wallet should be able to convert lower denom coins into high denom coins
Descriptionin an acceptable exchange smaller coins have higher relative fee than big denoms
this will impact the user after some time: it will perceive higher fees

some things to consider to make the scenario less probable:
 * since fee is in the order of cents, reducing the tx fee for the customer makes this scenario less probable (STEFAN curves)
 * if the merchant accepts to pay some fee then the wallet has a margin to use smaller coins

Still, using the wallet for a long period will lead to small coins due to random prices and change.

what the wallet could do is send all the fresh-and-small coins to the exchange for the exact amount of a bigger coin and receive one new fresh coin.

this operation:
 * is not something interesting for the customer (no need to show as a tx)
 * should trigger automatically (maybe before doing a payment)
 * is naturally limited, it can't be done indefinitely many time since is always converting from lower to higher denoms and converge to the highest denom (it can be potentially for free)

TagsNo tags attached.


Christian Grothoff

2023-09-14 15:17

manager   ~0020511

I disagree, this should not be necessary if the coin does reasonable coin selection on payments.

Christian Grothoff

2023-09-14 15:18

manager   ~0020512

Furthermore, it is dangerous as it may create (even accidentally!) a link between transactions.


2023-09-14 16:36

developer   ~0020513

* exchange: denoms $1 and $0.1 , all fee zero except deposit fee 0.01
 * wallet withdraws 9 coins of $1
 * merchant sells at $0.9

 * after buying 9 times, the wallet will have `$0.1 * 9` coins
 * the 10th payment will cost 10% in fee instead of 1%

Christian Grothoff

2023-09-14 16:43

manager   ~0020514

Only because of the *extreme* denomination structure of demo. Try the same with the canonical binary distribution of denominations.

Issue History

Date Modified Username Field Change
2023-09-14 15:11 sebasjm New Issue
2023-09-14 15:11 sebasjm Status new => assigned
2023-09-14 15:11 sebasjm Assigned To => Florian Dold
2023-09-14 15:17 Christian Grothoff Note Added: 0020511
2023-09-14 15:18 Christian Grothoff Note Added: 0020512
2023-09-14 15:18 Christian Grothoff Assigned To Florian Dold =>
2023-09-14 15:18 Christian Grothoff Priority normal => none
2023-09-14 15:18 Christian Grothoff Status assigned => feedback
2023-09-14 16:36 sebasjm Note Added: 0020513
2023-09-14 16:36 sebasjm Status feedback => new
2023-09-14 16:37 sebasjm Status new => feedback
2023-09-14 16:43 Christian Grothoff Note Added: 0020514
2023-12-24 06:29 Christian Grothoff Assigned To => Christian Grothoff
2023-12-24 06:29 Christian Grothoff Status feedback => closed
2023-12-24 06:29 Christian Grothoff Resolution open => won't fix
2023-12-24 06:29 Christian Grothoff Fixed in Version => 0.9.4
2023-12-24 06:29 Christian Grothoff Product Version => git (master)
2023-12-24 06:29 Christian Grothoff Target Version post-1.0 => 0.9.4