On Sat, Feb 21, 2009 at 9:37 PM, pi song <pi.so...@gmail.com> wrote: > 1) Hadoop file system is very optimized for mostly read operation > 2) As of a few months ago, hdfs doesn't support file appending. > There might be a bit of impedance to make them go together. > However, I think it should a very good initiative to come up with ideas to > be able to run postgres on distributed file system (doesn't have to be > specific hadoop).
In theory, I think you could make postgres work on any type of underlying storage you like by writing a second smgr implementation that would exist alongside md.c. The fly in the ointment is that you'd need a more sophisticated implementation of this line of code, from smgropen: reln->smgr_which = 0; /* we only have md.c at present */ Logically, it seems like the choice of smgr should track with the notion of a tablespace. IOW, you might to have one tablespace that is stored on a magnetic disk (md.c) and another that is stored on your hypothetical distributed filesystem (hypodfs.c). I'm not sure how hard this would be to implement, but I don't think smgropen() is in a position to do syscache lookups, so probably not that easy. ...Robert -- Sent via pgsql-hackers mailing list (pgsql-hackers@postgresql.org) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-hackers