RE: what could cause a high elap value for the exec system call (for a select statement)?

From: D'Hooge Freek <Freek.DHooge@xxxxxxxxx>
To: "mwf@xxxxxxxx" <mwf@xxxxxxxx>, 'Daniel Fink' <daniel.fink@xxxxxxxxxxxxxx>, "tim@xxxxxxxxx" <tim@xxxxxxxxx>, "Brandon.Allen@xxxxxxxxxxx" <Brandon.Allen@xxxxxxxxxxx>
Date: Wed, 4 Nov 2009 15:07:44 +0100

Mark,

Am I correct to say that, for a select statement, the exec call includes all 
the work (except parsing) that needs to be done to construct the cursor and 
that the fetch call includes all the work that needs to be done to retrieve 
rows from that cursor?


Regards,

 
Freek D'Hooge
Uptime
Oracle Database Administrator
email: freek.dhooge@xxxxxxxxx
tel +32(0)3 451 23 82
http://www.uptime.be
disclaimer: www.uptime.be/disclaimer



-----Original Message-----
From: oracle-l-bounce@xxxxxxxxxxxxx [mailto:oracle-l-bounce@xxxxxxxxxxxxx] On 
Behalf Of Mark W. Farnham
Sent: woensdag 4 november 2009 14:47
To: D'Hooge Freek; 'Daniel Fink'; tim@xxxxxxxxx; Brandon.Allen@xxxxxxxxxxx
Cc: 'Oracle-L@xxxxxxxxxxxxx'
Subject: RE: what could cause a high elap value for the exec system call (for a 
select statement)?

I'm pretty sure Tim meant that in the context a whole heck of a lotta work
must occur before you know what the first row to return is.

Another example is if you have a union (non-all) and the source datasets of
the parts of the union don't have a provable joint subkey, then you have to
do full projection of all the columns in the parts of the queries and sort
the resultset for duplicate rejection before you return anything. Something
like that with 1000 columns in the select list would be a really bad joke to
play on a computer system.

Please do correct me if I got that wrong, Tim.

mwf
--
http://www.freelists.org/webpage/oracle-l

Follow-Ups:

Re: what could cause a high elap value for the exec system call (for a select statement)?
From: Cary Millsap

References:
- what could cause a high elap value for the exec system call (for a select statement)?
  - From: D'Hooge Freek
- Re: what could cause a high elap value for the exec system call (for a select statement)?
  - From: Daniel Fink
- RE: what could cause a high elap value for the exec system call (for a select statement)?
  - From: D'Hooge Freek
- RE: what could cause a high elap value for the exec system call (for a select statement)?
  - From: Mark W. Farnham

RE: what could cause a high elap value for the exec system call (for a select statement)?

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