Parse/Exec./Fetch 'count' interpretation in tkprof output file

From: Spendius <spendius_at_muchomail.com>
Date: 2 Dec 2005 02:25:03 -0800
Message-ID: <1133519103.713988.178820@f14g2000cwb.googlegroups.com>

Hello,
We have a query that performs lots of logical I/O's. Here is the stats part
of a tkprof analysis:

call count cpu elapsed disk query current

    rows
------- ------ -------- ---------- ---------- ---------- ----------

---

Parse        4      0.04       0.22          0          0          0
       0
Execute      4      0.03       0.00          0          0          0
       0
Fetch        8     87.40     509.93     103180    2262849        502

   20100
------- ------ -------- ---------- ---------- ---------- ----------

---

total 16 87.47 510.16 103180 2262849 502

   20100

Our block size is 4 kilos on this DB, => so I deduced from this table that 4 executions of this query had to access (2262849+502)*4096= 9,270,685,696 bytes of data in memory => 1 execution traverses 2,317,671,424 = 2.15 gigs of data, or am I wrong ? The guy who wrote this query tells me "no you're wrong you have to divide by 8 fetches, and not
4 executions, which means it only has to access half of these 2.15 gigs"...

Who's right ?

Thanks.
Spendius Received on Fri Dec 02 2005 - 04:25:03 CST