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Implementing a Social Graph using Redis

• petercooper 16y ago
  Because Redis requires the entire dataset to reside in memory. It doesn't: http://code.google.com/p/redis/wiki/VirtualMemorySpecification http://code.google.com/p/redis/wiki/VirtualMemorySpecificati... .. Well, in the classical "in memory" sense. Virtual memory is a sort of memory.. :-)
  • jpcx01 16y ago
    In practical terms, under scale, it's pretty much the case. If you don't have enough memory to have your entire dataset in memory, the performance degrades to a point where it'll be too slow to do anything, so it might as well not work at all. Similar problems with MongoDB. Anytime your indexed data starts hitting disk, kiss your site goodbye. Sharding seems like the proper workaround though, so maybe you could take the same approach of flockdb and shard the redis social graph.
    • stephencelis 16y ago
      the performance degrades to a point where it'll be too slow to do anything Do you have any examples? In my experience, Redis is pretty fast even when it lives partially in VM. You can get boxes with a ton of RAM these, days, though, and if you go beyond it, you can always shard/distribute the database, like you mention.