Re: Optimize cascade deletes

From: Michael Gentry (blacknex..mail.com)
Date: Sat Sep 22 2007 - 08:45:38 EDT

  • Next message: Giulio Cesare Solaroli: "Re: Optimize cascade deletes"

    FWIW:

    I run PostgreSQL on OS X and it is plenty fast enough. The downside
    to PostgreSQL on OS X is there isn't an installer, so it is more work
    to build and install. If you are Unix-savvy, though, this won't be
    much of a problem.

    I've used PostgreSQL on Windows, too, which works alright overall.
    One thing that really harmed performance for me on Windows, though,
    was virus scanners and Pointsec, which does full HD encryption -- the
    combination of virus scanning every read/write + encryption really
    applies the brakes. Speaking of encryption, do you have File Vault
    turned on under OS X? If so, is your Parallels VM running on that
    file system? I'd imagine that would really harm performance.

    /dev/mrg

    On 9/22/07, Andrus Adamchik <andru..bjectstyle.org> wrote:
    >
    > On Sep 21, 2007, at 7:45 PM, Giulio Cesare Solaroli wrote:
    >
    > >
    > > [18:09:40] DELETE FROM clipperz.RCRVRS WHERE ID_RCRVRS = ?
    > > [18:09:40] [batch bind: 968]
    > > [18:09:40] [batch bind: 875]
    > > [......]
    > > [18:09:40] [batch bind: 1177]
    > > [18:09:40] [batch bind: 2792]
    > > [18:11:54] === updated 68 rows.
    > >
    > > In this case, to delete just 68 rows it took more than two minutes,
    > > but I don't know if this time is spent somewhere inside the cayenne
    > > code, or if this is simply the time it took PostgreSQL to "physically"
    > > delete the rows.
    >
    > Initially I suspected performance problems with faulting the
    > relationships, but if the delete itself is so slow, it points to
    > PostgreSQL as the bottleneck as Ari said (coincidentally the query
    > above is a BatchDeleteQuery generated by Cayenne). If it takes that
    > long, something is wrong with the DB. I second a suggestion to try
    > installing PostgreSQL on Mac and it without Parallels.



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