Re: cpu time and query column in tkprof output

From: jaromir nemec <jaromir_at_db-nemec.com>
Date: Thu, 3 Feb 2005 23:39:30 +0100
Message-ID: <009a01c50a41$3be91450$3c02a8c0@JARAWIN>

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_at_centrexcc.com> To: "Cary Millsap" <cary.millsap_at_hotsos.com> Cc: <yasbs_at_kocbank.com.tr>; <oracle-l_at_freelists.org> Sent: Wednesday, February 02, 2005 4:49 PM Subject: Re: cpu time and query column in tkprof output

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Received on Thu Feb 03 2005 - 17:42:23 CST