Re: cpu time and query column in tkprof output
- From: "jaromir nemec" <jaromir@xxxxxxxxxxxx>
- To: <oracle-l@xxxxxxxxxxxxx>
- Date: Thu, 3 Feb 2005 23:39:30 +0100
Hi,
> Whenever I have done comparisons of different sql to produce the same
> result, the bytes sent via SQL*Net were always the same - maybe wrong,
> but at least consistently wrong.
I completely agree. I performed some tests with sample query (that return
the length of its own statement in bytes)
select (count(*)-1) * length('select * from dual union all ') + 94 from (
select * from dual union all
select * from dual union all
select * from dual union all
select * from dual union all
select * from dual union all
< add some rows here to get different statement lengths>
select * from dual
);
Bytes received seems to have a systematic error (the value is about 1KB
*less* then the length of SQL statement) , so small values are probably
meaningless.
Bytes sent seems to be - in this count(*) case - stabile. Note the switch
from 345 to 346 for higher numbers.
Regards
Jaromir
Some results - Length of SQL Statement compared with bytes received
(COUNT(*)-1)*LENGTH('SELECT*FROMDUALUNIONALL')+94
-------------------------------------------------
239
345 bytes sent via SQL*Net to client
503 bytes received via SQL*Net from client
(COUNT(*)-1)*LENGTH('SELECT*FROMDUALUNIONALL')+94
-------------------------------------------------
1254
345 bytes sent via SQL*Net to client
503 bytes received via SQL*Net from client
(COUNT(*)-1)*LENGTH('SELECT*FROMDUALUNIONALL')+94
-------------------------------------------------
2414
345 bytes sent via SQL*Net to client
1121 bytes received via SQL*Net from client
(COUNT(*)-1)*LENGTH('SELECT*FROMDUALUNIONALL')+94
-------------------------------------------------
4734
345 bytes sent via SQL*Net to client
3477 bytes received via SQL*Net from client
(COUNT(*)-1)*LENGTH('SELECT*FROMDUALUNIONALL')+94
-------------------------------------------------
9374
345 bytes sent via SQL*Net to client
8190 bytes received via SQL*Net from client
(COUNT(*)-1)*LENGTH('SELECT*FROMDUALUNIONALL')+94
-------------------------------------------------
18654
346 bytes sent via SQL*Net to client
17615 bytes received via SQL*Net from client
(COUNT(*)-1)*LENGTH('SELECT*FROMDUALUNIONALL')+94
-------------------------------------------------
130014
346 bytes sent via SQL*Net to client
130715 bytes received via SQL*Net from client
----- Original Message -----
From: "Wolfgang Breitling" <breitliw@xxxxxxxxxxxxx>
To: "Cary Millsap" <cary.millsap@xxxxxxxxxx>
Cc: <yasbs@xxxxxxxxxxxxxx>; <oracle-l@xxxxxxxxxxxxx>
Sent: Wednesday, February 02, 2005 4:49 PM
Subject: Re: cpu time and query column in tkprof output
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