On Saturday, July 30th 2016, the fourth meetup in the Hack And Learn series was held at the Ethereum Office Berlin. Samuli Pöyhtäri presented IPFS (interplanitary filesystem) and orbit-db a database-system that runs on said filesystem. Samuli works at Protocol Labs, the company behind IPFS and the lead-developer of orbit-db. The meeting was attended by a dozen people, most of them developers who had already some experience with IPFS.
Samuli gave an overview over IPFS (see also http://www.propellah.net/2016/03/13/the-permanent-web-for-music-and-other-media-content/) and the peer-to-peer database orbit-db which runs on top of IPFS. A truly decentralized database-system is still a big gap in available decentralized systems.
Right now the options for developers of decentralized systems are either distributed hash tables (DHT) and blockchains. Examples for systems that use DHTs are Bittorrent and Openbazaar. An Example for blockchains that can be used to store data are Namecoin and Ethereum. However these systems cannot compete with conventional databases in terms of query speed and they offer less ways to query data. Typically DHTs and blockchains can only be used as key-value-stores, which means that values can only be retrieved by the value. Conventional database systems like MySQL or PostgreSQL offer many more ways to organise data, build relations between datapoints and select them. However these conventional systems require a centralized server to run and cannot be used in a decentralized context.
Orbit-DB (similarily to https://www.bigchaindb.com/)aims to bring some of the benefits of traditional database systems to the world of decentralized applications. As of yet however Orbit-DB still requires a centralized server for pubsub-communication, however the IPFS-team works on a decentralized pubsub service. According to Samuli Orbit-DB will switch to this pubsub-service as soon as it is finished. He added that this task is not trivial though.
After the very informative and interesting presentation, there was the opportunity to ask questions and chat with other IPFS users. I highly recommend the Hack And Learn meetups as a place to get to know new technology, play around with it!