Re: [HACKERS] Execution time. - Mailing list pgsql-hackers

From Shiby Thomas
Subject Re: [HACKERS] Execution time.
Date
Msg-id 199802041626.LAA01859@cise.ufl.edu
Whole thread Raw
In response to Re: [HACKERS] Execution time.  ("Vadim B. Mikheev" <vadim@sable.krasnoyarsk.su>)
Responses Re: [HACKERS] Execution time.  (The Hermit Hacker <scrappy@hub.org>)
List pgsql-hackers
=> > 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




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