RE: I/O times
- From: "John Kanagaraj" <john.kanagaraj@xxxxxxx>
- To: <adar666@xxxxxxxxxxxx>, <ORACLE-L@xxxxxxxxxxxxx>
- Date: Mon, 5 Jun 2006 15:22:05 -0700
Yechiel,
The issue with this SQL is that you will get incorrect results if you
had a Db restart in between. I use the following segment to get the data
out of STATSPACK tables. Change it as required for Start/end
dates/DBMS_OUTPUT/etc. It will take care of Db restarts and display a
per day I/O summary:
declare
v_fname varchar2(30);
v_rds number;
v_wrt number;
v_blk_rds number;
v_blk_wrt number;
v_begin_id perfstat.stats$filestatxs.snap_id%TYPE;
v_end_id perfstat.stats$filestatxs.snap_id%TYPE;
l_FileHandle UTL_FILE.FILE_TYPE;
l_FileDir Varchar2(100) := '/usr/tmp';
l_FileName Varchar2(100) := '';
v_end_date DATE;
v_curr_date DATE;
/* This Cursor fetches the min and max snap id for a given day. It also
makes sure that there was no DB restart inbetween */
cursor snapshot is
select min(snap_id), max(snap_id)
from perfstat.stats$snapshot
where trunc(snap_time) = trunc(v_curr_date)
and startup_time =
(select min(startup_time)
from perfstat.stats$snapshot
where trunc(snap_time) = trunc(v_curr_date)) ;
/* This Cursor fetches the sysstat values given the min and max snap id
for a given day fetched by the previous cursor */
cursor filestat is
select substr(e.filename,1,40) name,
e.phyrds - b.phyrds phyrds, e.phywrts - b.phywrts phywrts,
e.phyblkrd - b.phyblkrd phyblkrd, e.phyblkwrt - b.phyblkwrt phyblkwrt
from perfstat.stats$filestatxs b, perfstat.stats$filestatxs e
where b.filename = e.filename
and ( e.phyrds - b.phyrds ) > 1000
and b.snap_id = v_begin_id and e.snap_id = v_end_id;
begin
-- dbms_output.enable (9999999);
l_FileName := 'file_io.dat';
l_FileHandle := utl_file.fopen(l_FileDir, l_FileName, 'w');
v_curr_date := to_date('01-JAN-03');
v_end_date := to_date('13-JUL-05');
LOOP
open snapshot;
LOOP
fetch snapshot into v_begin_id, v_end_id;
exit when snapshot%NOTFOUND;
open filestat;
loop
fetch filestat into v_fname, v_rds, v_wrt,
v_blk_rds, v_blk_wrt;
exit when filestat%NOTFOUND;
utl_file.put_line(l_FileHandle, v_curr_date || ',' || v_fname
|| ',' || to_char(v_rds) || ',' ||
to_char(v_wrt) || ',' || to_char(v_blk_rds)
|| ',' || to_char(v_blk_wrt));
end loop;
close filestat;
END LOOP;
close snapshot;
v_curr_date := v_curr_date + 1;
exit when trunc(v_curr_date) = trunc(v_end_date);
END LOOP;
utl_file.fclose(l_FileHandle);
end;
/
Regards,
John Kanagaraj <><
DB Soft Inc
Phone: 408-970-7002 (W)
http://www.klove.com - Positive, encouraging music 24x7 worldwide
** The opinions and facts contained in this message are entirely mine
and do not reflect those of my employer or customers **
-----Original Message-----
From: oracle-l-bounce@xxxxxxxxxxxxx
[mailto:oracle-l-bounce@xxxxxxxxxxxxx] On Behalf Of Yechiel Adar
Sent: Monday, June 05, 2006 1:17 AM
To: ORACLE-L@xxxxxxxxxxxxx
Subject: I/O times
Hello
I am doing a gross checking of performence.
Since we do regular snapshots, I wanted to see the I/O times during
March and June.
Is the following good enough:
-- Mb stands for Multi Block, SB stands for Single Block.
select to_char(snap_time,'MM/DD') day ,
sum(phyrds) MB_read , sum(readtim) MB_time , sum(phyrds) /
sum(readtim) single_mb_time ,
sum(SINGLEBLKRDS) SB_read, sum(SINGLEBLKRDTIM) SB_time,
sum(SINGLEBLKRDS) / sum(SINGLEBLKRDTIM) single_SB_time,
sum(phywrts) WRITES, sum(writetim) WRITES_TIME, sum(phywrts) /
sum(writetim) SINGLE_WRITE_TIME
from STATS$FILESTATXS a , STATS$SNAPSHOT b
where tsname = 'USERS'
and a.snap_id = b.snap_id and TO_CHAR(b.snap_time, 'MM') in
('03','06')
and to_char(snap_time,'HH') < '08'
group by to_char(snap_time,'MM/DD')
order by to_char(snap_time,'MM/DD')
--
Adar Yechiel
Rechovot, Israel
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