Difference between revisions of "Libbitcoin Blockchain"

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The [https://github.com/libbitcoin/libbitcoin-blockchain libbitcoin-blockchain] library is a dependency of [[Libbitcoin_Node|libbitcoin-node]] and [[Libbitcoin_Server|libbitcoin-server]]. It was originally contained within [[Libbitcoin_Common|libbitcoin]].
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The [https://github.com/libbitcoin/libbitcoin-blockchain libbitcoin-blockchain] library is a dependency of [[Libbitcoin_Node|libbitcoin-node]] and [[Libbitcoin_Server|libbitcoin-server]]. The library provides transaction and block validation as well as transaction (memory) and block (orphan) pools.
  
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==Example==
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==Consensus Validation==
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    #include <string>
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By default the library depends on the [[Libbitcoin_Consensus|libbitcoin-consensus]] library and its use can be selected by run time configuration. This ensures that consensus checks are identical to those implemented by [[Bitcoind|bitcoind]]. By building using the ''--without-consensus'' flag the dependency is avoided and [[Libbitcoin|libbitcoin]] native consensus checks are used instead.
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    #include <bitcoin/blockchain.hpp>
 
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    // Initialize the blockchain
 
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    int main(int argc, char* argv[])
 
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    {
 
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        std::string prefix("blockchain");
 
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        if (argc > 1)
 
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            prefix = argv[1];
 
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        bc::chain::initialize_blockchain(prefix);
 
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        bc::chain::db_paths paths(prefix);
 
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        constexpr size_t history_height = 0;
 
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        bc::chain::db_interface interface(paths, { history_height });
 
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        interface.start();
 
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        const auto genesis = bc::genesis_block();
 
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        interface.push(genesis);
 
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        return 0;
 
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    }
 
  
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==Design==
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==History==
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The original implementation used [http://leveldb.org LevelDB]. Following a redesign in late 2014 by [[Amir_Taaki|Amir Taaki]] (genjix) the database was replaced by a memory-mapped I/O implementation. Logical queries are performed using a set of hash tables. The number of hash buckets is optimized to minimize hash collisions, though collisions are accommodated. These changes resulted in a substantial performance increase for queries against the blockchain. Insert performance is was not materially affected and queries are near constant time.
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* The blockchain was originally contained within [[Libbitcoin_Common|libbitcoin]] and contained [[Libbitcoin_Database|libbitcoin-database]].
  
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[[Image:Libbitcoin-blockchain-gets.png|500px]] [[Image:Libbitcoin-blockchain-gets-normalised.png|500px]]
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==Dependencies (Version2)==
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* [http://www.boost.org boost]
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* [https://github.com/bitcoin/secp256k1 secp256k1]
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* [[Libbitcoin_Common|libbitcoin]]
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* [[Libbitcoin_Consensus|libbitcoin-consensus (optional)]]
  
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==Considerations==
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==Dependencies (Version3)==
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* There is no mechanical hard drive optimization. The implementation is intended for solid state drives ([http://en.wikipedia.org/wiki/Solid-state_drive SSD]).
 
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* There is a possibility of index corruption during hard shutdown. There is no means of detecting corruption aside from catastrophic fault. However given that the entire blockchain is a cache this is not considered significant. Repair can be accomplished by re-synchronizing the blockchain.
 
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* Data files are append only, with logical deletions only. Therefore file size is not minimized following blockchain reorganization although the impact is typically small. Defragmentation can be accomplished by re-synchronizing the blockchain.
 
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* The database is effectively locked during write operations. As these operations are anticipated on a period of approximately ten minutes this is not typically significant. However during a period of catch-up synchronizing the server can become continuously unresponsive to requests.
 
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==Dependencies==
 
 
* [http://www.boost.org boost]
 
* [http://www.boost.org boost]
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* [https://github.com/bitcoin/secp256k1 libsecp256k1]
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* [https://github.com/bitcoin/secp256k1 secp256k1]
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* [[Libbitcoin_Consensus|libbitcoin-consensus]] (optional)
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* [[Libbitcoin_Common|libbitcoin]]
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* [[Libbitcoin_Database|libbitcoin-database]]
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* [[Libbitcoin_Consensus|libbitcoin-consensus (optional)]]
  
 
==See Also==
 
==See Also==
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==References==
 
==References==
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[[Category:Open Source]]
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[[Category:Software‏‎]]

Revision as of 08:37, 8 March 2017

The libbitcoin-blockchain library is a dependency of libbitcoin-node and libbitcoin-server. The library provides transaction and block validation as well as transaction (memory) and block (orphan) pools.

Consensus Validation

By default the library depends on the libbitcoin-consensus library and its use can be selected by run time configuration. This ensures that consensus checks are identical to those implemented by bitcoind. By building using the --without-consensus flag the dependency is avoided and libbitcoin native consensus checks are used instead.

History

Dependencies (Version2)

Dependencies (Version3)

See Also

References

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