Since when is redo log writing
performance handled by DB_WRITERS
or DBWR_IO_SLAVES?
Cheers
Nuno Souto
[EMAIL PROTECTED]
- Original Message -
Now, the Sr DBA here is screaming about the performance since I made the
change,
in particular, he says he's seeing high redo latch contention
There could be some interaction.
If DBWR needs to write a block for
which the most recent changes are in
the log buffer but not in the log file, then
DBWR posts LGWR to write - and in
earlier versions of Oracle DBWR would
then wait for LGWR to sync, in later versions
DBWR links the buffer to a
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Steve,
By distinct user do you mean distinct username? Or sid/serial#
combination? In my case, we use connection pooling, while there may be
up to 300 sessions, they are all the same named user.
Rachel
--- Steve Adams [EMAIL PROTECTED] wrote:
Hi All,
Someone has alerted me to this thread,
how do you feel about connection pooling? Our software engineers implemented
that here? Am I wrong to be concerned about large numbers of users using the
same named user?
- Original Message -
To: Multiple recipients of list ORACLE-L [EMAIL PROTECTED]
Sent: Saturday, January 10, 2004 6:39
I can understand the concern about ingesting large amount of data. We ingest
about 200 GB a night. To get around the archiving problem we make a
noarchivelog 'staging' instance, to run our loads. Then we use transportable
tablespaces to move the data to production. Its alot quicker and easier to
Yes, I hadn't read the line
so the tablespaces had to be put into backup mode or (8i and after) the
database had to be suspended
you _do_ have an OR between the backup mode and the database .. suspended.
We hadn't heard of anyone using the SUSPEND and didn't want to take the chance
of a database
It's always a little hard to tell from a low-concurrency
experiment how bad things can be at high concurrency.
(If it were easy, Cary wouldn't have had to have written
his book).
I have an example where a collision rate of 0.25%
results in an increase in response time of 8% at
relatively low
Note in-line
Regards
Jonathan Lewis
http://www.jlcomp.demon.co.uk
The educated person is not the person
who can answer the questions, but the
person who can question the answers -- T. Schick Jr
Next public appearance2:
March 2004 Hotsos Symposium - Keynote
March 2004 Charlotte NC -
Ryan:
Same named user with large number of connections is not a problem.
Things will become bad only IFF the large number of different users
using the same set of public synonymns.
KG
--- Ryan [EMAIL PROTECTED] wrote:
how do you feel about connection pooling? Our software engineers
I'm concerned about other problems. We may have 30,000 concurrent users,
sharing 5 or so named users. My big concern is maintenance and tracing.
Has anyone worked with this type of environment? How do you build tracing
into the front end so I can tell which sid, serial# is experience problems?
If you are on Oracle 9i, try connection identifier using
DBMS_SESSION.SET_IDENTIFIER for each of the client sessions. Even if teh
USERNAME in V$SESSION shows your named user, the field CLIENT_IDENTIFIER
will show the actual user (say, the application userid). The trace files
will show that, even
I think what you've demonstrated is
that pl/sql tables are not limited by
pga-aggregate target, and that a pl/sql
table can grow until it has taken up all
the available memory on your machine.
I'd guess that each element in your table
takes about the same space - with a little
error round the
Where does oracle store pl/sql tables? I have run into problems with
developers doing massive bulk collects and I have to bounce the entire
server...
- Original Message -
To: Multiple recipients of list ORACLE-L [EMAIL PROTECTED]
Sent: Saturday, January 10, 2004 12:54 PM
I think what
Hi!
If you intend to use roles to simplify privilege management, you are
almost forced to use public synonyms, as you cannot create a private
synonym owned by a role. Your other alternative is to hard-code the
How can you create a public synonym OWNED by a role?
This is new to me, despite the
Tanel,
I'm fairly sure that Rachel was not implying that a role
could own a synonym, public or private.
The point was that using role based privilege management,
you either create private synonyms for each user, or create
public synonyms.
Another alternative is a logon trigger that does an
Would it be incorrect to assume that you never do inserts
into newly loaded partitions, or updates that could increase
the length of rows?
1 pctfree could be problematic in that case.
Jared
On Sat, 2004-01-10 at 05:04, Ryan wrote:
I can understand the concern about ingesting large amount of
its read only data in production. we monitor for chained rows on our staging
environment and do table reorgs as necessary. Our staging server only
ingests data over night, so we have all day for reorgs. Or we can just do
them on weekends. We may do a handful every few months. We just run a script
Does anybody have any good resources (links/whitepapers) on setting up,
managing and monitoring an Oracle Standby environment?
I found Oracle Backup Recovery 101 by Stephan Haisley and Kenny Smith to
be useful.
Gudmundur
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Please see the official ORACLE-L FAQ: http://www.orafaq.net
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Having worked in an environment where every user was a distinct named
user, and I therefore could (and at points did) have something 1700
distinct connections (yes, I said one thousand seven hundred).
I like connection pooling. It limits the stress on the database,
because the number of
Tanel,
you can't create a public synonym owned by a role, sorry if I wasn't
clear. But public synonyms are available to all users, regardless of
the role you assign to the user. So you have to use public synonyms
when you use roles, unless you either specify the object owner name in
all
yep, that's what I meant :)
additionally, if you decide to create private synonyms for each user,
you still have the potential problem of forgetting a user when you add
a new synonym. Yes, I use SQL to generate the SQL I need but even so,
it's a lot easier to include create public synonym and
In the UGA, I should think (which also means the
SGA if you are running MTS). It can't be in the
PGA (ignoring the fact that the UGA is in the PGA
for non-MTS) or you couldn't have global pl/sql
tables that persist across database calls.
Regards
Jonathan Lewis
http://www.jlcomp.demon.co.uk
Rachel,
I think we had a similar situation in my previous life, when we had to get the programmers to modify their code to trace specific areas of the application. The way we went about doing this (in this case they had a concept of using a catalog.xml file where all the SQL queries got stored
I have seen people bulk collect into pl/sql tables so much data that you
cannot even connect to the server. So I'm assuming that ones the UGA fills
up, Oracle will allocate whatever unused memory is left on the server for
pl/sql tables?
- Original Message -
To: Multiple recipients of list
Gene - As a part of putting the database back in archivelog mode, I hope you
take another backup.
Dennis Williams
DBA
Lifetouch, Inc.
[EMAIL PROTECTED]
-Original Message-
Sent: Friday, January 09, 2004 4:44 PM
To: Multiple recipients of list ORACLE-L
I put all databases in archive
Ryan - I don't see where you received a direct answer to this question. To
use RMAN to back up to tape you must license what Oracle terms a MML (media
management library). However, you can use RMAN to back up to disk without
any additional purchase. My sys admin evaluated the cost of the MML piece
Hi Paula,
Paul and Steve have given some good ideas on this but also you should
lock down the database as hard as you can. Even if the database is only
accessed via the application server its data is still available from the
internet. Issues such as SQL Injection and cross site scripting can come
Something important to take into account when talking about security, is
the problem with if you don't know it's happening you can't stop it...
..
Remember to read/analyze logs for unusual stuff (Oracle or FW logs)...
preferably with an IDS, as it makes the job of finding out whether you
have a
Would it be incorrect to assume that you never do inserts
into newly loaded partitions, or updates that could increase
the length of rows?
1 pctfree could be problematic in that case.
Btw, if you're sure that rows won't grow, it use even pctfree 0 instead of
1. One thing you have to have in
Ryan,
As Jonathan mentioned, global PL/SQL tables are allocated from the UGA.
In MTS, they will be allocated from the SGA's large pool (or, in the event one
has not been defined, which is a big no-no for MTS, then from the shared pool.) Note
in this case, if the large_pool is insufficient to
On 2004.01.10 16:49, DENNIS WILLIAMS wrote:
Gene - As a part of putting the database back in archivelog mode, I hope you
take another backup.
Actually, taking backup should be a part of every major intervention on the database.
Changing the database mode from noarchivelog to archivelog most
Yeah, I configured RMAN on a system. Then the users didn't want me to turn
off cold backups. My response was that a DBA wouldn't say there was such a
thing as too many backups, so we do both.
Specifically with noarchivelog/archivelog, if you try to recover using a
backup from before you turned
Hi:
I have a program (running on oracle 8173 server) that writes 48 Millions
lines of data into various text files . The selected data is from various
tables and I have the query pretty much optimized. Now I am trying to find
the fastest way to dump the selected data into a text file on the same
Ok, thanks, this makes sense.
Tanel.
- Original Message -
To: Multiple recipients of list ORACLE-L [EMAIL PROTECTED]
Sent: Saturday, January 10, 2004 10:34 PM
yep, that's what I meant :)
additionally, if you decide to create private synonyms for each user,
you still have the
Jared has a utility to dump tables to flat files
http://www.cybcon.com/~jkstill/util/
on the lefthand menu, under Utilities click on Dump Tables to Flat
Files
--- Guang Mei [EMAIL PROTECTED] wrote:
Hi:
I have a program (running on oracle 8173 server) that writes 48
Millions
lines
Both the PGA and PL/SQL tables are stored in the data (a.k.a. heap)
section of process memory in the Oracle server process.
If using Solaris, running the pmap utility against the Oracle server
process is useful. I have a posted script named oramem.sh posted at
http://www.EvDBT.com/tools.htm;
Options #1 (Perl) and #2 (PRO*C) would be fastest and easiest. The PRO*C
demo programs provide a decent start, for option #2. Option #3 (OCI) would
be not faster than PRO*C and, due to the increased complexity of OCI, a more
problematic approach.
SQL*Plus is the easiest method to implement by
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