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1	Permissioned Blockchains and Distributed Databases : A Performance Study / Permissioned Blockkedjor och Distribuerade Databaser : En Prestanda Undersökning Bergman, Sara January 2018 (has links) Blockchain technology is a booming new field in both computer science and economicsand other use cases than cryptocurrencies are on the rise. Permissioned blockchains are oneinstance of the blockchain technique. In a permissioned blockchain the nodes which validatesnew transactions are trusted. Permissioned blockchains and distributed databasesare essentially two different ways for storing data, but how do they compare in terms ofperformance? This thesis compares Hyperledger Fabric to Apache Cassandra in four experimentsto investigate their insert and read latency. The experiments are executed usingDocker on an Azure virtual machine and the studied systems consist of up to 20 logicalnodes. Latency measurements are performed using varying network size and load. Forsmall networks, the insert latency of Cassandra is twice as high as that of Fabric, whereasfor larger networks Fabric has almost twice as high insert latencies as Cassandra. Fabrichas around 40 ms latency for reading data and Cassandra between 150 ms to 250 ms, thusit scales better for reading. The insert latency of different workloads is heavily affected bythe configuration of Fabric and by the Docker overhead for Cassandra. The read latency isnot affected by different workloads for either system. Blockchain Hyperledger Fabric Permissioned blockchain Distributed Database Cassandra Latency Distributed Systems Computer Engineering Datorteknik Software Engineering Programvaruteknik
2	Implications and Impact of Blockchain Transaction Pruning Palm, Emanuel January 2017 (has links) This thesis presents an extension to Hyperledger Fabric, a private blockchain system, allowing historic transactions to be pruned without peer coordination. The feature is facilitated via pruning predicate functions, provided along any smart contracts a given system is desired to host. An evaluation of the extension demonstrates its impact, in terms of memory saved, for a specific asset delivery use case. It is concluded that the gains of pruning historic transactions from blockchain systems could yield significantly reduced storage requirements for some categories of applications, especially such with low transaction interdependency. It is also suggested that the deterministic consensus algorithms used by Hyperledger Fabric makes the transaction histories it may maintain not strictly required, meaning that the particular set of transactions that must survive pruning depend on what properties a blockchain is expected to maintain. Blockchain blockchains hyperledger fabric hyperledger fabric private blockchain permissioned blockchain pruning cryptography computer science disk disk usage memory efficiency pruning predicate function Computer Sciences Datavetenskap (datalogi)

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Permissioned Blockchains and Distributed Databases : A Performance Study / Permissioned Blockkedjor och Distribuerade Databaser : En Prestanda Undersökning

Implications and Impact of Blockchain Transaction Pruning