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Home -> Community -> Mailing Lists -> Oracle-L -> RE: Log writer
thanks
Ross,
<FONT face=Arial
color=#0000ff size=2>MTS, I didn't know it was on? Isn't that just an
init.ora setting? I am looking in to finding out about the cache, but no
luck yet. The redo log buffer is 67,676 kb. Yes, this isn't some
normal little system where the duhvelopers are just querying the db, they are
constantly doing DML, lots of FTS. I have found so many indexes in the
USERS tablespace which puts them on the same HD as the tables they are
accessing. I move them, but somehow more seem to always
appear...hmmm..wonder why that is.
<FONT face=Arial
color=#0000ff size=2>But I am curious, when you say network/app tuning, what
exactly do you mean by that? I know that two disks aren't that great, but
not my idea, it was done before my dumbass got here, now I am just trying to fix
it. Everything else looks good on the system though, library_cache hit
ratio, buffer cache hit ratio all very high. It's just this program
occasionally, about every 10 minutes is telling me the logwriter is a
slouch.
<FONT face=Arial
color=#0000ff size=2>What about my other question though,
<FONT face=Arial color=#0000ff
size=2>
<FONT face=Arial color=#0000ff
size=2> MAXLOGFILES 32 MAXLOGMEMBERS
2 MAXDATAFILES 32 MAXINSTANCES 16 MAXLOGHISTORY 4764LOGFILE GROUP 11 (
<FONT face=Tahoma
size=2>-----Original Message-----From: root_at_fatcity.com
[mailto:root_at_fatcity.com]On Behalf Of Mohan, RossSent:
Thursday, March 22, 2001 12:21 PMTo: Multiple recipients of list
ORACLE-LSubject: RE: Log writer
Kev,
Pure
shot from hip:
<FONT face=Arial color=#0000ff
size=2>
I'd
say you have more network/app response tuning than log tuning.
I'd
say
you have more disk tuning ( for table/index reads) than log tuning. I
<FONT face=Arial color=#0000ff
size=2>would DEFINITELY turn the silly ass MTS off.
<FONT face=Arial color=#0000ff
size=2>
I'd
find out how to make sure disk cache is 4 MB and is
writeBACK
not
writeTHRU. ( if either ) <FONT
face=Arial color=#0000ff size=2>I'd have questions about the controller, too,
but.."later".
<FONT face=Arial color=#0000ff
size=2>
(You
didn't tell me the size of the redo log buffer...)
<FONT face=Arial color=#0000ff
size=2>
Of
course, having a two disk wonder (or whatever it is) is the
number
one
thing to work on.
<FONT face=Arial color=#0000ff
size=2>
In
any case, with your hardware, your system should easily be
able
to
handle a few users, in its sleep.
<FONT face=Arial color=#0000ff
size=2>
<FONT face=Arial color=#0000ff
size=2>There's about two dozen little tweaks you can do to perk things up a
bit,
but
basically, your "rock and a hard place" is going to be a two disk
wonder
on a
single controller...
<FONT face=Arial color=#0000ff
size=2>
<FONT face=Arial color=#0000ff
size=2>hth
<FONT face=Arial color=#0000ff
size=2>
<FONT face=Arial color=#0000ff
size=2>Ross
<FONT face=Arial color=#0000ff
size=2>
<FONT face=Arial color=#0000ff
size=2>
<FONT face="Times New Roman"
size=2>-----Original Message-----From: Kevin Kostyszyn
[mailto:kevin_at_dulcian.com]Sent: Thursday, March 22, 2001 11:31
AMTo: Multiple recipients of list ORACLE-LSubject: RE:
Log writer
<FONT face=Arial color=#0000ff
size=2>Jeez, Seagate Cheeta 18 and 36, 10k RPM
ahhh
UNFORMATTED CAPACITY (GB)
________________22.54 FORMATTED
CAPACITY (GB)
__________________18.21 AVERAGE
SECTORS PER TRACK ________________213 rounded
down ACTUATOR TYPE
____________________________ROTARY VOICE
COIL TRACKS
___________________________________167,008
CYLINDERS ________________________________6,962
user HEADS
______PHYSICAL______________________24
DISCS (3 in)
_____________________________12
MEDIA TYPE _______________________________THIN
FILM/MR RECORDING METHOD
_________________________PRML 8/9
______________________10,025 AVERAGE
LATENCY (mSEC)
___________________2.99 BUFFER
(/optional)
_______________________1MB/4MB
Read Look-Ahead,
I believe the only problem
is that they are on one controller. However, this is not a huge
database, only about 3-4 users connected at a time, but lots of DML.
The machine is a Dell Precision 410 with a gig of Ram and dual PIII
450's. I don't think that it's a huge problem, but it does keep coming
up. There are three log file groups of 32 MB's each and yes the
database is also spread accross these two platters.
Oh and the
results......YOINK!
<FONT face=Arial color=#0000ff
size=2>rdbms ipc
message
14980809SQL*Net message from
client
9595869pmon
timer
1880177virtual circuit
status
1877869smon
timer
1875449dispatcher
timer
1874318SQL*Net break/reset to
client
49746control file parallel
write
18026db file sequential
read
3947log file
sync
1456db file scattered
read
1017
size=2>EVENT
TIME_WAITED----------------------------------------------------------------
-----------log file parallel
write
616Null
event
411library cache
pin
315refresh controlfile
command
292reliable
message
273rdbms ipc
reply
146control file sequential
read
108log file switch
completion
58SQL*Net more data to
client
45enqueue
27file
identify
24
size=2>EVENT
TIME_WAITED----------------------------------------------------------------
-----------log file single
write
23latch
free
19SQL*Net message to
client
17file
open
16buffer busy
waits
13SQL*Net more data from
client
6direct path
read
5log file sequential
read
0db file parallel
write
0instance state
change
0direct path
write
0
size=2>EVENT
TIME_WAITED----------------------------------------------------------------
-----------LGWR wait for redo
copy
0
Disk mfr? rpm? <FONT
size=2>seek/access times? diskperf -y set
already? CPU,I/O, or diskbound system?
log buffer size? log file size? <FONT
size=2>what else is on the "separate" disks? anything? <FONT
size=2>separate disks share a controller? select
event, time_waited from v$system_event order by 2 desc; results?
just a few questions that come to mind....
-----Original Message----- From:
Kevin Kostyszyn [<A
href="mailto:kevin_at_dulcian.com">mailto:kevin_at_dulcian.com]
Sent: Thursday, March 22, 2001 8:50 AM <FONT
size=2>To: Multiple recipients of list ORACLE-L <FONT
size=2>Subject: Log writer
Hi all,
I am testing
out Spotlight on Oracle from Quest Software. It is telling me
that my log writer process is slow. What it looks
like it is saying is that most disks take about
20ms to right the data and mine is taking on average <FONT
size=2>about 40ms. I don't know why, they are scsi drives and there
isn't that much stress on the syste. Anyway,
I moved the redo logs to seperate disks, but I
fear I may have made an error. Instead of moving each "group"
to seperate hard disks, I moved the members of
each group to seperate hard disks. Anyway, I
am wondering if anyone has advice on this problem.
Sincerely, Kevin Kostyszyn
DBA Dulcian, Inc <FONT
size=2>www.dulcian.com kevin_at_dulcian.com
-- Please see the official
ORACLE-L FAQ: <A target=_blank
href="http://www.orafaq.com">http://www.orafaq.com <FONT
size=2>-- Author: Kevin Kostyszyn <FONT
size=2> INET: kevin_at_dulcian.com
Fat City Network Services -- (858)
538-5051 FAX: (858) 538-5051 San Diego,
California -- Public Internet
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Received on Thu Mar 22 2001 - 12:34:37 CST
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