showing 566,516 seconds wait for log buffer space. I would appreciate
if someone can explain.
Thanks
Top 5 Timed
Events
~~
% Total
Event
Waits Time (s) Ela Time
Subject: RE: log buffer space wait
I have one question regarding these wait times, may be dump. In the following wait events what is the unit of measurement for Time, I believe its in seconds as per the documentation. If yes then here stats are collected for only 51.23 Minutes (Appx 3073 second
-10 Dallas
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-Original Message-
DENNIS WILLIAMS
Sent: Tuesday, September 02, 2003 12:04 PM
To: Multiple recipients of list ORACLE-L
Vivek
Good question. At this point I haven't seen any replies to your
request.
The specific wait points to
After doing some reading on this, I suspect that your log files are too small.
I don't see any info on log file size in this post, or at least, I can't find it.
A large percentage of log buffer space waits occurr immediately after a
log switch, so if you're switching logs very
ginal Message -
From:
VIVEK_SHARMA
To: Multiple recipients of list ORACLE-L
Sent: Tuesday, September 02, 2003 4:39
PM
Subject: log buffer space wait
At a Benchmark a
particular Processing + DML intensive batch Job (Accounts Interest
Calculation) is experie
: Tuesday, September 02, 2003 12:04 PM
To: Multiple recipients of list ORACLE-L
Vivek
Good question. At this point I haven't seen any replies to your
request.
The specific wait points to the log buffer itself as being too small,
not
particularly the redo logs themselves. Your init.ora param
Vivek
Good question. At this point I haven't seen any replies to your request.
The specific wait points to the log buffer itself as being too small, not
particularly the redo logs themselves. Your init.ora parameters show this
buffer as being only 10-meg. I would suggest you increase it
11:29 AMTo:
Multiple recipients of list ORACLE-LSubject: Re: log buffer space
wait
Note:
This message is for the named person's use only. It may contain
confidential, proprietary or legally privileged information. No
confidentiality or privilege is waived or lost by any mistransmi
At a Benchmark a particular Processing
+ DML intensive batch Job (Accounts Interest Calculation) is experiencing
“log buffer space”
wait .
Config :-
On Solaris 9
Cpu_count = 72
Oracle 9.2
Online Redo logfiles are on a
RAID 0+1 Volume (NOT Raw or RAID 1) Log_buffer = 10 M
$ sar
Avnish ,
As far as log buffer is considered , look at how much redo ur generating .
That will be help you in finding optimal size of log buffer .
-ak
- Original Message -
To: "Multiple recipients of list ORACLE-L" <[EMAIL PROTECTED]>
Sent: Tuesday, August 05, 2003 4:54
What are the things I should monitor to make sure that Shared Pool and Log buffer are
set correctly. On one database I have Shared pool GAB and Log buffer MOB, are these
values too high.
Thanks
DISCLAIMER:
This message is intended for the sole use of the individual to whom it is addressed
KG,
I got the direct mail much quicker than the
list mail - but I'll just echo the doubt I raised
in the original.
If you use 10046 level 8 to watch for log writer
writes, I would expect you to see writes that
could be of an almost arbitrary size.
Assume a 3MB log buffer - we '
redo write.
Check the redo size for M and M+1 rows.
Under both 8.1.7.4 and 9.2.0.2, I found that
log writer seemed to be consistently triggered
at a couple of KB below 1/3 of the log_buffer.
(One oddity that caused me a little hassle with
9.2 at first was that I set the log buffer to 512K,
but the a
2.0.2, I found that
log writer seemed to be consistently triggered
at a couple of KB below 1/3 of the log_buffer.
(One oddity that caused me a little hassle with
9.2 at first was that I set the log buffer to 512K,
but the actual log buffer size (per v$sga) was
actually closer to 640K, so the tr
Arup:
Sorry for the delay ;-)
I have not seen this is documented anywhere, other than
'Oracle Performance Tuning' OReilly Peter & Mark Gurry
(page 304) where he claims the log writer writes when
it is 2/3 full... Here is the Original Text.
Log Buffer
The log buffer contains t
It's a fantastic ratio :-).
Anjo Kolk wrote:
1 log switch per minute ;-)
AK wrote:
log buffer is 320 K and log files are 30M approx. there are about 50 log
switch /hr .
-ak
- Original Message -
To: "Multiple recipients of list ORACLE-L" <[EMAIL PROTECTED]>
S
Dear AK,
So far we don't know your log buffer size.
Can we have a glimpse of this parameter, log_buffer ?
Rajesh
-Original Message-
Sent: Friday, March 14, 2003 8:14 PM
To: Multiple recipients of list ORACLE-L
Do you guys think , adding more log file can help ? I think it shoul
1 log switch per minute ;-)
AK wrote:
>
> log buffer is 320 K and log files are 30M approx. there are about 50 log
> switch /hr .
>
> -ak
>
> - Original Message -
> To: "Multiple recipients of list ORACLE-L" <[EMAIL PROTECTED]>
> Sen
hour is a bit much, but there are databases where 30
minutes of data lost could be quite hurtful.
>>> [EMAIL PROTECTED] 03/14/03 05:29PM >>>
Well, there lies your problem. I suggest you do the following in this order
of priority and see if they resolved the problem.
(1) Log
50 log switches per hour is a LOT. Get it down to a handful or so by increasing
the size of the redo logs with a factor 10 or so. Redo buffer sounds a bit
small, and going to 1M in size might help a bit, although there's no guarantee
for it.
Mogens
AK wrote:
log buffer is 320 K an
Well, there lies your problem. I suggest you do the following in this order
of priority and see if they resolved the problem.
(1) Log buffer of 320K is definitely small. Make it 4 MB (or at least 3MB)
if you have enough memory.
(2) Your log switching is 50 per hour?!! That's a little too
log buffer is 320 K and log files are 30M approx. there are about 50 log
switch /hr .
-ak
- Original Message -
To: "Multiple recipients of list ORACLE-L" <[EMAIL PROTECTED]>
Sent: Friday, March 14, 2003 9:29 AM
> AK,
>
> Could you provide the redo log
l Message-
> Sent: Friday, March 14, 2003 8:59 AM
> To: Multiple recipients of list ORACLE-L
>
>
> KG,
>
> Thanks for the response. Just for my curiosity, is it documented
> somewhere that the log buffer if flushed when 2/3rd full? From the
> Manual /server.920/a96524/c09
Arup
I have a busy day, so the only resource I can quote without research is
the Oracle Education Oracle9i Database Performance Tuning Student Guide.
Lesson 5-3 reads: "When the redo log buffer is one-third full". Hope that
answers your question.
Dennis Williams
DBA, 40%OCP, 100% DBA
40%OCP, 100% DBA
> Lifetouch, Inc.
> [EMAIL PROTECTED]
>
>
> -Original Message-
> Sent: Friday, March 14, 2003 8:59 AM
> To: Multiple recipients of list ORACLE-L
>
>
> KG,
>
> Thanks for the response. Just for my curiosity, is it documented
> somewher
ssage-
> Sent: Friday, March 14, 2003 8:59 AM
> To: Multiple recipients of list ORACLE-L
>
>
> KG,
>
> Thanks for the response. Just for my curiosity, is it documented somewhere
> that the log buffer if flushed when 2/3rd full? From the Manual
> /server.920/a96524/c09pro
Title: RE: log buffer space
I think this might help...
http://www.ixora.com.au/tips/tuning/log_buffer_size.htm
-Original Message-
From: Deshpande, Kirti [mailto:[EMAIL PROTECTED]]
Sent: Friday, March 14, 2003 11:19 AM
To: Multiple recipients of list ORACLE-L
Subject: RE: log
BA
Lifetouch, Inc.
[EMAIL PROTECTED]
-Original Message-
Sent: Friday, March 14, 2003 8:59 AM
To: Multiple recipients of list ORACLE-L
KG,
Thanks for the response. Just for my curiosity, is it documented
somewhere that the log buffer if flushed when 2/3rd full? From the
Manual /server.920/a96524/
ED]>
> Sent: Friday, March 14, 2003 4:32 AM
>
>
> > Arup:
> >
> >
> > The second condition is not quite true. It is 2/3 full in the current
> > versions.
> >
> >
> > It is very easy to test with the event 10046^8.
> >
> > KG
&
> --- Arup Nanda <[EMAIL PROTECTED]> wrote:
> > AK,
> >
> > If the log buffer is at least 4MB, then increasing it will not help,
> > rather it may hurt. The log buffer is flushed when any of the the
> > follwoing occur
> > (i) 1 MB is filled up
>
Are there any equations which can say log buffer is
small or large ? I mean how to find the proper size of log buffer .
-ak
- Original Message -
From:
Deshpande, Kirti
To: Multiple recipients of list ORACLE-L
Sent: Thursday, March 13, 2003 5:13
PM
Subject: RE
What's the size of your log buffer, and the redo log file?
Do you see any errors/messages in alert.log file that are related to 'checkpoints' or
'log switching'?
- Kirti
-Original Message-
Sent: Friday, March 14, 2003 10:14 AM
To: Multiple recipients of li
recipients of list ORACLE-L
KG,
Thanks for the response. Just for my curiosity, is it documented somewhere
that the log buffer if flushed when 2/3rd full? From the Manual
/server.920/a96524/c09procs.htm#3158 (please check the URL in OTN, the first
part is not complete), here is an excerpt
LGWR
4:32 AM
> Arup:
>
>
> The second condition is not quite true. It is 2/3 full in the current
> versions.
>
>
> It is very easy to test with the event 10046^8.
>
> KG
>
>
> --- Arup Nanda <[EMAIL PROTECTED]> wrote:
> > AK,
> >
> > If
KG,
Thanks for the response. Just for my curiosity, is it documented somewhere
that the log buffer if flushed when 2/3rd full? From the Manual
/server.920/a96524/c09procs.htm#3158 (please check the URL in OTN, the first
part is not complete), here is an excerpt
LGWR writes one contiguous
Arup:
The second condition is not quite true. It is 2/3 full in the current
versions.
It is very easy to test with the event 10046^8.
KG
--- Arup Nanda <[EMAIL PROTECTED]> wrote:
> AK,
>
> If the log buffer is at least 4MB, then increasing it will not help,
> rather it
AK,
If the log buffer is at least 4MB, then increasing
it will not help, rather it may hurt. The log buffer is flushed when any of the
the follwoing occur
(i) 1 MB is filled up
(2) 1/3rd is filled up
(3) every 3 seconds
(4) when a checkpoint occurs
(5) when a commit occurs.
Therefore, see
:[EMAIL PROTECTED]Sent: Thursday, March 13, 2003 4:49
PMTo: Multiple recipients of list ORACLE-LSubject: log
buffer space
I am finding tons of "log buffer space"
waits in 10046 output . Does it necessarily means I should look for resizing
log_buffer ? What else can be done or lo
I am finding tons of "log buffer space" waits
in 10046 output . Does it necessarily means I should look for resizing
log_buffer ? What else can be done or looked at to reduce these waits
.
Thanks,
ak
271
> 0493
> 1.81918819 236
>
> 27file
> open
> 4 0 0
>0 0
>
>The log_buffer_space wait event looks like is the culprit with
> total_wait =298, total_timeout = 271, and time_waited = 29267 ( 1/
Hi Greg,
Thanks. But we do not want to pay another $ 200K for the partioning
license.
Vasu
Greg Moore wrote:
> If you have purchased the partitioning option, you may be able to partition
> the table in a way that will allow you to drop the partition that contains
> all the rows you want t
; "Vasu Ramasamy" <[EMAIL PROTECTED]>
> Sent by: [EMAIL PROTECTED]
> 06/26/2002 09:49 AM
> Please respond to ORACLE-L
>
>
> To: Multiple recipients of list ORACLE-L <[EMAIL PROTECTED]>
> cc:
> Subject:Deleting larg
t; Personally, I'd be pretty happy with a 400K row delete
> > only taking 10 minutes.
> >
> > Jared
> >
> > "Vasu Ramasamy" <[EMAIL PROTECTED]>
> > Sent by: [EMAIL PROTECTED]
> > 06/26/2002 09:49 AM
> > Please respond to ORA
.
>
> Jared
>
> "Vasu Ramasamy" <[EMAIL PROTECTED]>
> Sent by: [EMAIL PROTECTED]
> 06/26/2002 09:49 AM
> Please respond to ORACLE-L
>
>
> To: Multiple recipients of list ORACLE-L
<[EMAIL PROTECTED]>
> cc:
> Subject:
If you have purchased the partitioning option, you may be able to partition
the table in a way that will allow you to drop the partition that contains
all the rows you want to delete. It's much faster to drop a partition
containing 400K rows than to delete 400K rows.
--
Please see the official
masamy" <[EMAIL PROTECTED]>
Sent by: [EMAIL PROTECTED]
06/26/2002 09:49 AM
Please respond to ORACLE-L
To: Multiple recipients of list ORACLE-L <[EMAIL PROTECTED]>
cc:
Subject:Deleting large table and the correct log buffer size
Hello Gurus,
u Ramasamy" <[EMAIL PROTECTED]>
Sent by: [EMAIL PROTECTED]
06/26/2002 09:49 AM
Please respond to ORACLE-L
To: Multiple recipients of list ORACLE-L <[EMAIL PROTECTED]>
cc:
Subject:Deleting large table and the correct log buffer size
Hello Gu
> To: Multiple recipients of list ORACLE-L <[EMAIL PROTECTED]>
> cc:
> Subject:Deleting large table and the correct log buffer size
>
> Hello Gurus,
> Ours is basically a Sybase shop. But moving towards Oracle. We are in
> the proces
ze of the redo
> log file?
100MB
> May be increasing it may help.
>
> What is the redo size per commit?
> Use this query to find out RSPC:
> select r.value / decode (c.value, 0, 1, c.value) RSPC
> from v$sysstat r, v$sysstat c
> where r.name = 'redo size'
L PROTECTED]>
cc:
Subject:Deleting large table and the correct log buffer size
Hello Gurus,
Ours is basically a Sybase shop. But moving towards Oracle. We are in
the process of conversion. I have a problem in deleting a large number
of rows. To delete 400,000 rows approx., it
per commit?
Use this query to find out RSPC:
select r.value / decode (c.value, 0, 1, c.value) RSPC
from v$sysstat r, v$sysstat c
where r.name = 'redo size'
and c.name = 'user commits';
You can use RSPC to size log buffer by multiplying it by number of user
commi
Hi Alexandre,
The checkpoint and log file switch are happening every 4 to 5 minutes. I
will try to increase the soze of the redo log file.
When I reduced the log buffer from 20MG to 4 MG, the log buffer space wait
event stats has just doubled. I am really confused with this params value
Vasu,
I think you should increase the size of your redo log files to make log
switches at average once every 10-30 mins.
I wouldn't make redo log buffer more than several Megs.
Alexandre
- Original Message -
To: "Multiple recipients of list ORACLE-L" <[EMAIL PROTECTED
of a second). Are these normal values for this wait event? The log
buffer init param is set to 20MB. To set up the init params, we took the
advice of the consultant DBA who worked for a short time (6 months) to
help us to set up servers. While I was going through the DBA hand books,
( 101 Oracle
h International, Sussex, WI
USA
>
> > -Original Message-
> > From: Kevin Kostyszyn [mailto:[EMAIL PROTECTED]]
> > Sent: Friday, March 23, 2001 14:06
> > To: Multiple recipients of list ORACLE-L
> > Subject: RE: Log Buffer
> >
> >
> > y
Title: RE: Log Buffer
v$filestats data?
just curious
-Original Message-
From: Kevin Kostyszyn [mailto:[EMAIL PROTECTED]]
Sent: Friday, March 23, 2001 4:05 PM
To: Multiple recipients of list ORACLE-L
Subject: RE: Log Buffer
Oops,
All right, I give up, I am dumb.
Kev
base Administrator
[EMAIL PROTECTED] Quad/Tech International, Sussex, WI USA
> -Original Message-
> From: Kevin Kostyszyn [mailto:[EMAIL PROTECTED]]
> Sent: Friday, March 23, 2001 14:06
> To: Multiple recipients of list ORACLE-L
> Subject: RE: Log Buffer
>
>
>
against to some degree in 8i.
It is very rare to a lot of a benefit once your log
buffer gets more than 512k.
hth
connor
--- Kevin Kostyszyn <[EMAIL PROTECTED]> wrote: > Hello
DBA's
> You know, I read somewhere that you can make your
> log_buffer 10 percent of
> your tota
of a benefit once your log
buffer gets more than 512k.
hth
connor
--- Kevin Kostyszyn <[EMAIL PROTECTED]> wrote: > Hello
DBA's
> You know, I read somewhere that you can make your
> log_buffer 10 percent of
> your total sga. So if you had a 500mb sga you could
>
The recommendation of 10% is very misinformed...Large
log buffers can actually hurt performance, although
this is protected against to some degree in 8i.
It is very rare to a lot of a benefit once your log
buffer gets more than 512k.
hth
connor
--- Kevin Kostyszyn <[EMAIL PROTECTED]>
Title: RE: Log Buffer
:-)...that's what I do: ask the experts.
But,
it's a moving target!
take
care
-Original Message-From: Kevin Kostyszyn
[mailto:[EMAIL PROTECTED]]Sent: Friday, March 23, 2001 3:06
PMTo: Multiple recipients of list ORACLE-LSubject: RE:
yes, I think that does help. I am thinking I am going to make them larger?
21 requests
-Original Message-
Sent: Friday, March 23, 2001 2:46 PM
To: 'Kevin Kostyszyn '
Hi...
I don't think so...
you must adjust your LOG_BUFFER acoording to:
select substr(name,1,25) Name,
subst
Title: RE: Log Buffer
Yeah,
illustrioius, that's good thing isn't it? Isn't that what someone called
Lord Vador in Star Wars.noo non no, it was Jabba the hut. Ok, I take
back the illustrious, I'll think of some other large word that sounds
cool!
I
don't, it
Title: RE: Log Buffer
"illustrious"?
oh my. I can see I am going to have to be
even more frivolous, irreverent, and non-topical.
..."gee, if I had a 4 GB SGA,
I guess i'd need a 400 Megabyte log buffer...yea,
sure, that makes sense"
-Original
Hello DBA's
You know, I read somewhere that you can make your log_buffer 10 percent of
your total sga. So if you had a 500mb sga you could have a 50 mb
log_buffer? What do you guys think, the illustrious Ross doesn't like such
large log_buffers.
Sincerely,
Kevin Kostyszyn
DBA
Dulcian, I
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