Thread

1. Re: [HACKERS] Execution time.

   Shiby Thomas <sthomas@cise.ufl.edu> — 1998-02-04T16:26:11Z

   => > I invoked postmaster as:
   => >  postmaster -B 30000 -o "-s -F -S 16384"
   =>                  ^^^^^
   => 240M of shared memory ?!
   => 
   Is the size of the hash bucket dependent on the number of buffers available ?
   If so, with -B 30000, it might create huge hash buckets and hence the
   hash join could degenerate to a nested loops join. Is that possible -- just
   checking. What could be good values for -B and -S. The largest table I am
   joining is about 60M
   
   Thanks
   --shiby
   
   
   
   
   

2. Re: [HACKERS] Execution time.

   Marc G. Fournier <scrappy@hub.org> — 1998-02-04T16:38:04Z

   On Wed, 4 Feb 1998, Shiby Thomas wrote:
   
   > 
   > => > I invoked postmaster as:
   > => >  postmaster -B 30000 -o "-s -F -S 16384"
   > =>                  ^^^^^
   > => 240M of shared memory ?!
   > => 
   > Is the size of the hash bucket dependent on the number of buffers available ?
   > If so, with -B 30000, it might create huge hash buckets and hence the
   > hash join could degenerate to a nested loops join. Is that possible -- just
   > checking. What could be good values for -B and -S. The largest table I am
   > joining is about 60M
   
   	My production server runs with a -B 256, and a -S 10240