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From: Riccardo Casatta <riccardo.casatta@gmail•com>
To: Gregory Maxwell <greg@xiph•org>,
	 Bitcoin Protocol Discussion
	<bitcoin-dev@lists•linuxfoundation.org>
Subject: Re: [bitcoin-dev] BIP 158 Flexibility and Filter Size
Date: Fri, 18 May 2018 10:46:29 +0200	[thread overview]
Message-ID: <CADabwBCKe6DaiBf_sjz9zyirkw8BdsDZnWSLEiAABEZvVDwj-Q@mail.gmail.com> (raw)
In-Reply-To: <CAAS2fgRF-MhOvpFY6c_qAPzNMo3GQ28RExdSbOV6Q6Oy2iWn1A@mail.gmail.com>

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Another parameter which heavily affects filter size is the false positive
rate which is empirically set
<https://github.com/bitcoin/bips/blob/master/bip-0158.mediawiki#construction>
to 2^-20
The BIP recall some go code
<https://github.com/Roasbeef/bips/blob/83b83c78e189be898573e0bfe936dd0c9b99ecb9/gcs_light_client/gentestvectors.go>
for how the parameter has been selected which I can hardly understand and
run, it's totally my fault but if possible I would really like more details
on the process, like charts and explanations (for example, which is the
number of elements to search for which the filter has been optimized for?)

Instinctively I feel 2^-20 is super low and choosing a lot higher alpha
will shrink the total filter size by gigabytes at the cost of having to
wastefully download just some megabytes of blocks.


2018-05-17 18:36 GMT+02:00 Gregory Maxwell via bitcoin-dev <
bitcoin-dev@lists•linuxfoundation.org>:

> On Thu, May 17, 2018 at 3:25 PM, Matt Corallo via bitcoin-dev
> <bitcoin-dev@lists•linuxfoundation.org> wrote:
> > I believe (1) could be skipped entirely - there is almost no reason why
> > you'd not be able to filter for, eg, the set of output scripts in a
> > transaction you know about
>
> I think this is convincing for the txids themselves.
>
> What about also making input prevouts filter based on the scriptpubkey
> being _spent_?  Layering wise in the processing it's a bit ugly, but
> if you validated the block you have the data needed.
>
> This would eliminate the multiple data type mixing entirely.
> _______________________________________________
> bitcoin-dev mailing list
> bitcoin-dev@lists•linuxfoundation.org
> https://lists.linuxfoundation.org/mailman/listinfo/bitcoin-dev
>



-- 
Riccardo Casatta - @RCasatta <https://twitter.com/RCasatta>

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  parent reply	other threads:[~2018-05-18  8:46 UTC|newest]

Thread overview: 60+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2018-05-17 15:25 Matt Corallo
2018-05-17 15:43 ` Peter Todd
2018-05-17 15:46   ` Matt Corallo
2018-05-17 16:36 ` Gregory Maxwell
2018-05-17 16:59   ` Matt Corallo
2018-05-17 18:34     ` Gregory Maxwell
2018-05-17 18:34     ` Gregory Maxwell
2018-05-17 20:19       ` Jim Posen
2018-05-17 20:45         ` Gregory Maxwell
2018-05-17 21:27           ` Jim Posen
2018-05-19  3:12             ` Olaoluwa Osuntokun
2018-05-21  8:35               ` Johan Torås Halseth
2018-05-22  1:16                 ` Olaoluwa Osuntokun
2018-05-22  9:23                   ` Johan Torås Halseth
2018-05-23  0:42                     ` Jim Posen
2018-05-23  7:38                       ` Jim Posen
2018-05-23  8:16                         ` Johan Torås Halseth
2018-05-23 17:28                         ` Gregory Maxwell
2018-05-24  1:04                           ` Conner Fromknecht
2018-05-24  3:48                             ` Jim Posen
2018-05-28 18:18                               ` Tamas Blummer
2018-05-28 18:28                                 ` Tamas Blummer
2018-05-28 19:24                                   ` Gregory Maxwell
2018-05-29  2:42                                     ` Jim Posen
2018-05-29  3:24                                       ` Gregory Maxwell
2018-05-29  4:01                                       ` Olaoluwa Osuntokun
2018-05-31 14:27                                         ` Tamas Blummer
2018-06-01  2:52                                         ` Olaoluwa Osuntokun
2018-06-01  4:15                                           ` Gregory Maxwell
     [not found]                                           ` <CAAS2fgSyVi0d_ixp-auRPPzPfFeffN=hsWhWT5=EzDO3O+Ue1g@mail.gmail.com>
2018-06-02  0:01                                             ` Olaoluwa Osuntokun
2018-06-02  0:22                                               ` Gregory Maxwell
2018-06-02  2:02                                                 ` Jim Posen
2018-06-02 12:41                                                   ` David A. Harding
2018-06-02 22:02                                                     ` Tamas Blummer
2018-06-03  0:28                                                       ` Gregory Maxwell
2018-06-03  5:14                                                         ` Tamas Blummer
2018-06-03  6:11                                                           ` Pieter Wuille
2018-06-03 16:44                                                             ` Tamas Blummer
2018-06-03 16:50                                                               ` Tamas Blummer
2018-06-08  5:03                                                             ` Olaoluwa Osuntokun
2018-06-08 16:14                                                               ` Gregory Maxwell
2018-06-08 23:35                                                                 ` Olaoluwa Osuntokun
2018-06-09 10:34                                                                   ` David A. Harding
2018-06-12 23:51                                                                     ` Olaoluwa Osuntokun
2018-06-09 15:45                                                                   ` Gregory Maxwell
2018-06-12 23:58                                                                     ` Olaoluwa Osuntokun
2018-05-18  8:46   ` Riccardo Casatta [this message]
2018-05-19  3:08     ` Olaoluwa Osuntokun
2018-05-19  2:57   ` Olaoluwa Osuntokun
2018-05-19  3:06     ` Pieter Wuille
2018-05-22  1:15       ` Olaoluwa Osuntokun
2018-05-18  6:28 ` Karl-Johan Alm
2018-06-04  8:42   ` Riccardo Casatta
2018-06-05  1:08     ` Jim Posen
2018-06-05  4:33       ` Karl-Johan Alm
2018-06-05 17:22         ` Jim Posen
2018-06-05 17:52       ` Gregory Maxwell
2018-06-06  1:12     ` Olaoluwa Osuntokun
2018-06-06 15:14       ` Riccardo Casatta
2018-05-19  2:51 ` Olaoluwa Osuntokun

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