Topic: libbitcoin - page 12. (Read 92493 times)

I'm just providing immediate access to both to compare them more easily...

The Zen sounds pretty much like Python's.

Congratulations! And great work.


We're getting closer to a high-level interface?

Big milestone reached! libbitcoin is the one of the first alternative implementations of the bitcoin protocol (along with node-bitcoin-p2p) to do full blockchain validation! Exciting milestone. It's taken me around 6 hours to download and validate the blockchain.

Here's a sample of validation times at 130k blocks in milliseconds:

112	22	97	316	0
38	407	1795	375
116	51	116	358
81	481	49	325
87	107	18	9
579	56	65	7
2329	98	25	103
8	4	291	155
147	140	185	55
87	15	31	67
12	47	28	16
12	34	92	0

Also I wrote a development statement for libbitcoin (also in the OP).

The Zen of libbitcoin
Readability over speed.
Beauty over convenience.
Simplicity over complexity.
Architected, not hacked.
Flat, not nested.
Explicit, not implicit.
Errors should be loud.
Never is better than right now.
Now is better than never.
Be flexible and configurable.
Build houses from bricks, software from modules.
Stability is god.

Random bitcoin trivia:

First transaction is in block 170

First standard transaction in block 728

The first difficulty change was at block 32256

Blocks 91842 and 91812, and, 91880 and 91722 contain the same duplicate coinbase transaction. The miners can only use that transaction once.
http://blockexplorer.com/block/00000000000a4d0a398161ffc163c503763b1f4360639393e0e4c8e300e0caec
http://blockexplorer.com/block/00000000000743f190a18c5577a3c2d2a1f610ae9601ac046a38084ccb7cd721

2016 (amount of blocks for difficulty re-calculation) corresponds to exactly 2 weeks of 10 minute ideal blocks. 210k (amount of blocks for drop in mining reward) only roughly corresponds to 4 years.

There was a forced fork in the blockchain a while back around 710k blocks when someone DoS bitcoin's scripting system using an excessive number of OP_CHECKSIGs. That's why IsStandard() exists today.

Block 142312 was the first block to have a non-standard coinbase. I think this was one of luke-jr's blocks possibly since it follows his pattern of instant spend.

block 546 spends a tx within the same block: 6b0f8a73a56c04b519f1883e8aafda643ba61a30bd1439969df21bea5f4e27e2

Image on how branch deletion works:

Monitoring this thread as I build a g++ capable of building libbitcoin.

Meditating on "block-chain verifier subsystem."

Hey, genjix here, posting under someone else's account

It's in the repo, https://gitorious.org/libbitcoin/libbitcoin/blobs/master/bitcoin.sql

Love your work genjix.

Without downloading the postgresql dump, can you please post the DDL for your schema here or provide just a dump of the schema.

I am very interested in creating a full data model (with ERD's, key discovery, propositions etc...) for Bitcoin using the Relational Model.
After that is created, I would like to help create a transition model for existing accounting/monetary based software packages to incorporate Bitcoins....

I am willing to provide schema's for all major DBMS packages (Mysql, SQL Server, Oracle, DB2 and Postgress)

I am a DBA/modeller with 25 years experience and quite frankly do not have the time ATM to read and collate the schema from the raw code.

No, don't worry. The conversation is informative. I have no problems if people want to talk about tangential topics here

I uploaded a postgresql dump of the database: https://bitcointalksearch.org/topic/bitcoin-network-database-dump-in-postgresql-download-link-inside-38246

Well if the BDB transaction fails, there will be no pointers to the extra crap at the end of the flat file and subsequent blocks will be added later, so all that would happen would be a bit of extra space would be wasted (in theory).  Not quite ACID but not quite leaving the database in an "inconsistent" state.
Anyway, I think weve overtaken this thread enough...

Writing blocks to a flat file is not very ACID, and there is no attempt at something analogous to BEGIN TRANSACTION/COMMIT when updating the block chain or indices, so a failure part-way through a reorg is very likely to leave the database in an inconsistent state.  Granted, both of these problems are outside of BDB and do not reflect on the strength or weakness of BDB.

I would say that bitcoin is effectively using a NoSQL "style" by not taking advantage of consistency guarantees, or of a relational model, both of which I think it would benefit from.

The type of NoSQL the poster was talking about here appears to be the non-ACID type of which BDB is not one of...

Berkeley DB, as it's being used in the existing bitcoin client, is a perfect example of why not to use NoSQL.

BAD idea. NoSQL is only faster because it doesn't do all that ACID checking that transaction-safe RDBMS does. While it's perfectly fine for data that doesn't need to be consistent i.e. nobody's going to particularly care if half the world saw your twit #156483 and the other half only get updated to #156482 for the next 2 minutes. But for financial transaction, having inconsistent data and no referential integrity is malpractice and asking outright to be scammed.

NoSQL is entirely a buzzword and has no meaning whatsoever.  Asking if they will support NoSQL is like asking if they will support about 30 different databases with completely different structures and APIs.

SQL isnt the problem here, its ACID.  If you throw ACID out the window, there are a ton of things you can do to increase performance, which is the reason some of the NoSQL solutions can benchmark so well.  If you are doing something with financial software, not using ACID is about as stupid as you can get (for the actual financial stuff, maybe for the blockchain where you have a bit more leeway and are only updating once every ~10 minutes anyway...)
I can't speak for xelister, but I dont think supporting JSON matters here as its a whole new lib anyway so whether or not the original bitcoin client supports JSON or not is fairly irrelevant.

And what about noSQL databases? Everyone says that they are faster and more scalable than SQL. Moreover MongoDB have interface in JSON, so it fits with default bitcoind interface.

Thanks.

I'm disconnecting from the forums for a few days to focus. I can be contacted using my email on the front of bitcoin.org

This is great work.  I'm looking forward to trying out the python API.  Thank you.

I plan to add a flag indicating whether an output is_final (and the parent transaction is_final - if all child outputs all have is_final set) and an output_address and for transaction a transaction_type (standard, generated and other) fields.

Also will be another table with chain_id, cumulative_difficulty... and cumulative difficulty in blocks.

For now still working on the block chain verification specifics (which algorithm is best and whether to organize then verify, pre-verify then organize then verify, or verify then link and organize). There are various pros and cons for all the different ways.

Ok that makes sense.  I am a bit concerned that even though the update is a single statement, it must touch a lot of rows, but it should be infrequent enough to not be a problem.

My next question is regarding the very common operation of determining whether an output has been spent.  Each output could be spent in a single transaction that belongs to multiple blocks (in separate forks) or by multiple transactions (also in separate forks).

So it seems that to determine if an output has been spent in a particular chain, you will have to query for all the inputs that spend the output, find (JOIN) the transactions that contain those inputs, find (JOIN) the blocks that contain those transactions, and see if any of those blocks have a span range that contains the chain in question.  I know databases are supposed to be good at this kind of thing but it sure sounds like a lot of work.  On the other hand, most of the transactions will not have a double-spend, so all the joining shouldn't make a difference in the most common case where there are no inputs that spend a txout.  All the joining might slow it down a bit when the blockchain forks, but a few extra indexed lookups shouldn't be that big a deal I guess.

I'm thinking I'll switch to your schema with the spans, because it bugs me how my version has dynamic fields marking whether a block is part of the 'best chain' and whether a txout has been spent in the current best chain.  It is a real headache to add a block to a fork other than the current best.