[oracle-l] Re: PL/Sql Update Table runs 38 hrs (so far)

Thanks.

Igor Neyman, OCP DBA
ineyman@xxxxxxxxxxxxxx



-----Original Message-----
From: oracle-l-bounce@xxxxxxxxxxxxx
[mailto:oracle-l-bounce@xxxxxxxxxxxxx] On Behalf Of Jonathan Lewis
Sent: Monday, January 26, 2004 3:41 PM
To: oracle-l@xxxxxxxxxxxxx
Subject: [oracle-l] Re: PL/Sql Update Table runs 38 hrs (so far)


That will work, given Wolfgang's assumption 
about uniqueness. But as it stands, Oracle will 
have to execute two subqueries for every row
in the 18,000,000 row table (I'm not sure that
any of the optimizer versions is currently smart
enough to convert his query into a hash join
with subquery update - but don't take my word
for that, I haven't tested it).

The pl/sql loop will make a maximum of 500,000
probes into the 18,000,000 row table to update.

(I think we are also both assuming that all three
of the join columns are not null, but the pl/sql
may behave contrary to the OP's expectations
if that were the case).



Regards

Jonathan Lewis
http://www.jlcomp.demon.co.uk

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----- Original Message ----- 
From: "Igor Neyman" <ineyman@xxxxxxxxxxxxxx>
To: <oracle-l@xxxxxxxxxxxxx>
Sent: Monday, January 26, 2004 8:33 PM
Subject: [oracle-l] Re: PL/Sql Update Table runs 38 hrs (so far)


Agreed.
What about modified code Wolfgang suggested?

Igor Neyman, OCP DBA
ineyman@xxxxxxxxxxxxxx

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