Re: performance tuning in large function / transaction

Hi all,

senario:

cursor 1 loop ( e.g. find student id )
cursor 2 loop ( e.g. find courses of this student )
cursor 3 loop ( e.g. update course information )
delele course detail ...
or
delete course detail ... ( same primary key )
insert course detail ... ( same primary key )
end loop 3
end loop 2
end loop 1

It did 75 delete actions 140 update actions ( delete
and insert ). The process time was about 5-6 minutes
while oracle was 10 seconds to 20 seconds .

postgresql.conf :
=================
shared_buffers = 3200
wal_buffers = 80

running on linux 7.1 , 512M ram.

M.T.

--- Stephan Szabo <sszabo(at)megazone23(dot)bigpanda(dot)com>
wrote:
> On Thu, 13 Dec 2001, MindTerm wrote:
>
> > Hi all,
> >
> > I will try to assign more memory to shared
> memory,
> > say 50M ~ 100M .
> >
> > I am runing something like that ..
> >
> > cursor loop 1
> > cursor loop 2
> > cursor loop 3
> > tmp = primary key
> > delete tmp ....
> > insert tmp ....
> > end loop 3
> > end loop 2
> > end loop 3
> >
> > will delete and insert record with same primary
> key
> > within a transaction reduce the performance ?
>
> Hmm, that might, is the tmp different for each
> combination of 1,2 and 3? I'm not really sure.
> You might also want to watch the backend's memory
> usage during the call to see how big it gets just
> to make sure there's not something bad happening.
>
>
>
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