coin selection code does very badly in some cases #1643

1. 
   dooglus commented at 7:47 pm on August 1, 2012: contributor

   Take a look at transaction ce9c9afee7b3dd1deebdc49ceb1560d2771acb4cd0a4725042beecde726a3463.

   He was trying to send 0.0011 BTC, and was charged 0.0445 in fees. That’s a 4045% charge. According to the user, there were “a lot of better fitting inputs”.

   The coin selection code doesn’t attempt to minimise fees. Perhaps it should.

   The transaction spent the following outputs:

   571 single satoshis, plus these 15 amounts which sum to 0.05559429:

   0.00007550 0.00009679 0.00011887 0.00014177 0.00019014 0.00042293 0.00045708 0.00049249 0.00056730 0.00134063 0.00178897 0.00187366 0.00196149 0.01070019 0.03536648

   If just the last of those 15 was used, the fee would have been either 0.0005 or 0.

2. 
   Xekyo commented at 1:03 am on September 13, 2014: member

   I have suggested an improvement at #4906 and would appreciate feedback.
3. 
   sipa commented at 5:45 pm on January 23, 2017: member

   I believe #9404 may also have improved upon this.
4. 
   MarcoFalke commented at 5:53 pm on January 23, 2017: member

   @sipa I don’t think so, but I might be wrong. The issue is that ApproximateBestSubset right now will try to create an exact match, as was the case when this issue was filed. The bug you are referencing solved a fee calculation bug.
5. laanwj removed the label Priority Medium on Apr 25, 2017
6. suprnurd referenced this in commit 5f0da8aa71 on Dec 5, 2017
7. MarcoFalke added the label TX fees and policy on Dec 20, 2017
8. 
   Sjors commented at 8:17 pm on March 16, 2018: member

   Recent discussion on coin selection #12605
9. 
   MarcoFalke commented at 8:00 pm on April 24, 2020: member

   Let’s discuss further steps in #12605
10. MarcoFalke closed this on Apr 24, 2020

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11. DrahtBot locked this on Feb 15, 2022

Contributors
dooglus Xekyo sipa MarcoFalke Sjors

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Wallet TX fees and policy