Re: Postgres as In-Memory Database?

Gavin Flower <GavinFlower@xxxxxxxxxxxxxxxxx> · Mon, 18 Nov 2013 13:02:32 +1300



    On 18/11/13 12:53, Stefan Keller wrote:

    
      Hi Martijn
        

        2013/11/17 Martijn van Oosterhout <kleptog@xxxxxxxxx> wrote:

          
        > If your dataset fits in memory
          then the problem is trivial: any decent

          > programming language provides you with all the necessary
          tools to deal

          > with data purely in memory.  
        

        What about Atomicity, Concurrency and
          about SQL query language and the extension mechanisms of
          Postgres? To me, that's not trivial.
        
          
        > There are also quite a lot of
          databases that cover this area.
        

        Agreed. That's what partially triggered
          my question, It's notably Oracle TimesTen, MS SQL Server 2014
          (project Hekaton), (distributed) "MySQL Cluster", SAP HANA or
          SQLite >3. To me this rather confirms that an architecture
          and/or configuration for in-memory could be an issue also in
          Postgres. 
        

          The actual architecture of Postgres
            assumes that memory resources are expensive and optimizes
            avoiding disk I/O. Having more memory available affects
            database design e.g. that it can optimize for a working set
            to be stored entirely in main memory. 
          

          --Stefan
          

    [...]

    
    It would allow optimised indexes that store memory pointers of
    individual records, rather than to a block & then search for the
    record - as well as other optimisations that only make sense when
    data is known to be in RAM (and RAM is plentiful).  As already big
    severs can have a TerraByte or more of RAM, that will become more
    & more common place.  I have 32GB on my development box.

    
    Cheers,

    Gavin