Subject: Re: [bitcoin-dev] Mempool "Expected Byte Stay" policy

From: Tom Harding <[email-masked]>
Date: Wed, 15 Jul 2015 16:15:24 -0700

On 7/15/2015 12:18 PM, Thomas Zander via bitcoin-dev wrote:
> On Tuesday 14. July 2015 17.24.23 Tom Harding via bitcoin-dev wrote:
>> Rule 2: A transaction and its dependents are evicted on its 2-hour
>> anniversary, whether space is required or not
> Instead of 2 hours, why not a number of blocks?

So users/wallets can know when they should rebroadcast and consider 
increasing the fee.

Using 12 blocks, there is a 5% chance he has to wait 3 hours.*

Using 120 minutes, there is only a .23% chance that fewer than 4 blocks 
have occurred.**

*
Table[{x, 1 - CDF[ErlangDistribution[12, 1/10], x]}, {x, 0, 240, 10}] 
//N //TableForm
0.      1.
10.    1.
20.    0.999999
30.    0.999929
40.    0.999085
50.    0.994547
60.    0.979908
70.    0.94665
80.    0.888076
90.    0.803008
100.    0.696776
110.    0.579267
120.    0.461597
130.    0.353165
140.    0.26004
150.    0.184752
160.    0.126993
170.    0.0846691
180.    0.0548874
190.    0.0346726
200.    0.0213868
210.    0.0129048
220.    0.00762994
230.    0.00442702
240.    0.00252413

**
Table[{x, CDF[PoissonDistribution[1/10 * 120], x]}, {x, 0, 20}] //N 
//TableForm
0.    6.14421*10^-6
1.    0.0000798748
2.    0.000522258
3.    0.00229179
4.    0.00760039
5.    0.020341
6.    0.0458223
7.    0.0895045
8.    0.155028
9.    0.242392
10.    0.347229
11.    0.461597
12.    0.575965
13.    0.681536
14.    0.772025
15.    0.844416
16.    0.898709
17.    0.937034
18.    0.962584
19.    0.97872
20.    0.988402