[bitcoin-dev] Using a storage engine without UTXO-index

Johnson Lau jl2012 at xbt.hk
Sat Apr 8 20:21:04 UTC 2017

> On 9 Apr 2017, at 03:56, Tomas <tomas at tomasvdw.nl> wrote:
>> I don’t fully understand your storage engine. So the following deduction
>> is just based on common sense.
>> a) It is possible to make unlimited number of 1-in-100-out txs
>> b) The maximum number of 100-in-1-out txs is limited by the number of
>> previous 1-in-100-out txs
>> c) Since bitcrust performs not good with 100-in-1-out txs, for anti-DoS
>> purpose you should limit the number of previous 1-in-100-out txs. 
>> d) Limit 1-in-100-out txs == Limit UTXO growth
>> I’m not surprised that you find an model more efficient than Core. But I
>> don’t believe one could find a model that doesn’t become more efficient
>> with UTXO growth limitation.
> My efficiency claims are *only* with regards to order validation. If we
> assume all transactions are already pre-synced and verified, bitcrust's
> order validation is very fast, and (only slightly) negatively effected
> by input-counts.

pre-synced means already in mempool and verified? Then it sounds like we just need some mempool optimisation? The tx order in a block is not important, unless they are dependent

>> One more question: what is the absolute minimum disk and memory usage in
>> bitcrust, compared with the pruning mode in Core?
> As bitcrust doesn't support this yet, I cannot give accurate numbers,
> but I've provided some numbers estimates earlier in the thread.
> Rereading my post and these comments, I may have stepped on some toes
> with regards to SegWit's model. I like SegWit (though I may have a
> slight preference for BIP140), and I understand the reasons for the
> "discount", so this was not my intention. I just think that the reversal
> of costs during peak load order validation is a rather interesting
> feature of using spend-tree  based validation. 
> Tomas

Please no conspiracy theory like stepping on someone’s toes. I believe it’s always nice to challenge the established model. However, as I’m trying to make some hardfork design, I intend to have a stricter UTXO growth limit. As you said "protocol addressing the UTXO growth, might not be worth considering protocol improvements*, it sounds like UTXO growth limit wouldn’t be very helpful for your model, which I doubt. 

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