Netty: All content tagged as Netty in NoSQL databases and polyglot persistence
Monday, 23 January 2012
Countandra: Cassandra-Based Hierarchical Distributed Counting Engine
Countandra features:
- Geographically distributed counting.
- Easy HTTP Based interface to insert counts.
- Hierarchical counting such as com.mywebsite.music.
- Retrieves counts, sums and square in near real time.
- Simple HTTP queries provides desired output in JSON format
- Queries can be sliced by period such as LASTHOUR, LASTYEAR and so on for MINUTELY, HOURLY, DAILY, MONTHLY values
- Queries can be classified for anything in hierarchy such as com, com.mywebsite or com.mywebsite.music
Inspired by Twitter’s Rainbird and built on top of Cassandra (1.0.1), Netty, Hector, and Joda.
Original title and link: Countandra: Cassandra-Based Hierarchical Distributed Counting Engine (©myNoSQL)
Friday, 23 September 2011
Memcached and Sherpa for Yahoo! News Activity Data Service
Mixer, the recently announced Yahoo’s new data service for news activities, uses Memcached and Sherpa for its data backend. Plus a combination of asynchronous libraries and task execution tools:
The data processing model and the clear separation between read and write data solutions is not only compelling, but essential for maintaining the SLA (max. 250ms/response):
Memcache maintains two types of materialized views: 1) Consumer-pivoted, and 2) Producer-pivoted. Consumer-pivoted views (e.g. user’s friends’ latest read activity) are refreshed at query time by refresh tasks. Producer-pivoted views (e.g. user’s latest read activity) are refreshed at update time (i.e. when “read” event is posted). And producer-pivoted views are used to refresh consumer-pivoted views.
Sherpa is Yahoo!’s cloud-based NoSql data store that provides low-latency reads and writes of key-value records and short range scans. Efficient range scans are particular important for the Mixer use cases. The “read” event is stored in the Updates table. The Updates table is a Sherpa Distributed Ordered Table that is ordered by “user,timestamp desc”. This provides efficient scans through a user’s latest read activity. A reference to the “read” record is stored in the UpdatesIndex table to support efficient point lookups. UpdatesIndex is a Sherpa Distributed Hash Table
Original title and link: Memcached and Sherpa for Yahoo! News Activity Data Service (©myNoSQL)
