Reg Instance Tuning

Hi Pals,
Can anyone help me out in 'Instance tuning'.The situation is like this- Bulk of simulated users hit the database and I need to tune the DB Oracle8.1.7
some points for consideration are CPU utilization,Memory tuning and contention.
Wat couple of parameters atleast u guys out there suggest to be considered for tuning?
I would appreciate pointers-books/links/tools to achieve this and to get more info and guidance.
Thanks and cheers,
sreek

You can go for tuning db block buffers, shared pool size at instance level. You can also tune short area size. However make sure that sum of memory allocated to sga does not exceed 50% of RAM. You can also go for application level tuning to improve ur database performance

Similar Messages

Reg: SQL Tuning Advisor -

Hi Experts,
A quick question regarding this utility: SQL Tuning Advisor.
Does this need any special license to use?
Or, any special Grants/Privileges required for it?
Please provide pointers for this.
-- Ranit

Or, any special Grants/Privileges required for it?
Grant-wise , a user needs the privilege ADVISOR

Reg: Instance shutdown in RAC

In Rac Environment , if node 1 fails user can get access from surviving instance from node2.but suppose node1 system is up and runnig, but if the instance is shutdown,
suppose there is service called demo it's preffered instance in running on node1, available instance is running on node2. Suppose user A is using service demo, can he get access.
please tel me.

Demo service is configured with instance1 as 'preferred instance'. So if instance1 is down the request for connection will be serviced by the available instance i.e. instance2 in that case. So a user connecting via demo service will be able to connect to DB via instance2, if instance1 is down.
Regards,
Pankaj Ranga

Reg: Instance

Hello all
I have a doubt regarding the instance. Does Oracle Instance stops automatically?
If yes, What are the possible reasons for instance stop
I am using Oracle 11g version 11.2.0.1

New_To_Oracle_7912 wrote:
Hello all
I have a doubt regarding the instance. Does Oracle Instance stops automatically?
If yes, What are the possible reasons for instance stop
I am using Oracle 11g version 11.2.0.1Change the word automatically to abruptly which would happen only because of someone doing something that would lead to instance get crashed, like a mandatory process being killed, some one pulling out the power plug(that would blow away the entire server itself though) or some severe error leading to this like 4031.
HTH
Aman....

RZ10 instance parameters on AIX 5.3 p595 - any advice?

Does anyone have parameters to share for ECC 6.0 EHP3 running IS-OIL? There are so many notes however I would like to see what is best practice in the real world. We have a decent size with several apps servers. I have set baseline using Note 789477 and 146289 however there are so many variations depending on the implementation.
Thanks
Mikie

> We have a decent size with several apps servers.
<irony-on>
Well - that is of course a concrete number everyone could give you an advise...
<irony-off>
Memory/instance tuning is an iterative process. If you have no clue how to configure the system for your load I would book an EarlyWatch service (that you get for free AFAIK if you go live with a new system), they can check the system data with tools and recommend good parameters for the initial start. However, you will need to tune after some days/weeks according to what you see on your system.
Markus

Does Oracle RAC improve performance over single-instance db

Hallo!i am running a single instance db that seems to be overwhelmed by workload as CPU is constantly 100% utilized despite code and instance tuning and users persistently complain of system slowness.
It is our plan to uprgade to more powerful servers but would also like to implement load balancing to have 2 instances and 2 servers share workload via RAC solution.
Some of peers state that RAC mostly a High Availability solution to enable continuity should one instance fail.I would like to know if db performance would improve on RAC as load balancing between 2 or more instances occurs in a RAC setup.
Thanks.

4joey1 wrote:
Some of peers state that RAC mostly a High Availability solution to enable continuity should one instance fail.I would like to know if db performance would improve on RAC as load balancing between 2 or more instances occurs in a RAC setup.RAC also provides scalability - as you have additional servers and database instances to deal with the workload. It is not a mere high availability and redundancy architecture.
BTW, a 2 node RAC is IMO not a "real" RAC... We also have one of those and I regret not insisting that it be, at minimum, a 4 node RAC - from both a redundancy/availability and performance/scalability viewpoints.
Simple example - on our bigger RAC we are dealing with about 37000+ row inserts every second (3+ billion rows per day). This workload is only handled (on smallish dual 2-core CPU servers) due to RAC. No way that a single one of these servers would alone (as a single non-RAC instance) be capable to deal with that workload.
So yeah - RAC is most definitely also about performance and scalability too. (but that does not mean it's a magic wand for solving your performance problems either).

Performance Tuning DBA fix not Applications fix

Hi
I had an interview , which the DBA team leader was asking me about my performance tuning expereince
i was answering about my expereince in tuning the sqls and get a good statistics so the CBO choose the best plan, or even hint my sqls so i force the best plan
the interviwer was worried because this is an application tuning , not a DBA tuning
he mention that he want to hear that i changed a db parameter that enhance the performance , or chnage any thing in the DBA side that tune the performance
Anybody have an example of changing a parameter or something DBAish that help the performance?
Thanks for any contribution

You should read following sections of Performance Tuning Guide:
Performance Considerations for Initial Instance Configuration:
http://download.oracle.com/docs/cd/B19306_01/server.102/b14211/build_db.htm#i20151
Memory Configuration and Use:
http://download.oracle.com/docs/cd/B19306_01/server.102/b14211/memory.htm#i53187
Oracle Instance Tuning Using Dynamic Views:
http://download.oracle.com/docs/cd/B19306_01/server.102/b14211/instance_tune.htm#i35312

Tuning Siebel Analytics

I have been assigned to monitor 10.1.3.2 Siebel Analytics release (Maui). Being new to this area, wanted pointers as to how to:
a. debug performance issues
b. trace database transactions - is there a way to enable trace?
c. improve performance of database servers
I have done a brief reading of <http://download.oracle.com/docs/cd/E05554_01/books/AnyTuning/booktitle.html>, are there any other reading material for performance tuning/instance tuning (ETL, database server etc.)
thanks.
Edited by: kkulkarn on Jan 26, 2009 1:40 PM

Try asking in the BI forum?
Business Intelligence Applications
Axel

Performance tuning of Oracle 9i Database

I want to know, what are the different parameters in the tuning of Oracle 9i database.
A few, i can list like
1) Re-building of indexes
2) Making the heavy transaction tables lighter
3) Checking if the indexes are firing
In a similar fashion, i needed what are the other parameters which can be a good indication of the health of the database. I hope, my question is clear.
Please, help in solving the doubt.
regards

Hmm there is parameter coming up called _<your db name>_fast=true in some later future release.Its still not implemented yet but expected to be coming up soon due to excessive demand.
Your list's first element only is the show-stopper.Richard Foote has talked extensively about this.Its almost never that a index is requiriing a rebuild.There should be benchmarks to prove the benefit (if any ) of the operation.Please visit his blog http://richardfoote.wordpress.com to readmore about this.
2) Making the heavy transaction tables lighter
I didnt get this one.
3) Checking if the indexes are firing
You mean by chance that they are in use or not?If yes than again this may not be the indication of the success truly.It may be possible that they are in use but not the right thing for the query.BTW indexes being used or not is not the database health check.Its the query's health check.
There are no certain parameters which needs to be on a cerain value.Every parameter and its value can have variation depending upon the environment,workload and most importantly release of the databse.If you want to benchmark your db's health ,I shall suggest take a STatspack report before the problem and when you see a variation in it and compare.This will give you the lead to find the bottleneck in the db's performance.Instance tuning(changing parameters) is the last resort or near to last one.
Aman....

[open] Performance of Database

Hello Gurus
I have around 5 databases Dev01,Dev02,Dev03,Dev04,Dev05 in my server
To increase the performance of one Dev04 DB i decrease the resources(sga_max_size,shared_pool_size,db_cache_size) for other DBs and increase the resources of Dev04 DB upto maximun extended
But i am observered the performance of Dev04 DB is poor
Is there any suggestion/tricks to increase or decraese resources for DB to perform better
Thanks in advance

It would be a little tough to say what to do with the information that you have provided. The first most important missing part is the database version(4 digits). Alot has changed with the versions so what and why can be different based on it.
It would be required for you to see that what's happening on the Dev 4 db that its slow. The parameters , even though given generously doesn't gurantee that there would be a performance boost all the time. If there is a hard parse issue in the statements itself than it won't matter how much shared pool you allocate,it will eventually get filled up. Changing the parameter and expecting performance gain is called instance tuning and its highly unlikely that it would be of much use.
You have mentioned high resource utilization in the db. Did you check that in the system itself is not choked up due to resource crunch? There are commands like sar, top, vmstat which can help you in doing this. The objective is to remove anything over the o/s itself which is causing it.
Once you are done with this, you should come to the db and check which are the areas that may have beocme the contention point,for example, due to heavy parsing of the statemen aka hard parsing of the statements, cpu would be used veyr heavily. This may cause the resource crunch also. The best way to check this would be to generate STatspack or AWR report, depending on the version of your db. Generate that and post it here than it would be a little accurate to advice you over the performance gain.
HTH
Aman....

Database Size

Hi,
Looking for answers of the following questions:
1) Can anybody tell me that how i can check the size of my database?
2) I am working in DSS environment and few of my tables are consist around 40000 rows. Can anybody tell me that how i can increase the performance of these table. These tables already have primary key unique index. what is the most possible ways to increase the performace of the query?
Regards,

Hi,
1/ you can get it via looking into the files size views:
DBA_DATA_FILES
DBA_TEMP_FILES
V$LOG
or example:# sqlplus system
SQL*Plus: Release 9.2.0.7.0 - Production on Me Nov 16 16:14:09 2005
Copyright (c) 1982, 2002, Oracle Corporation. All rights reserved.
Enter password:
Connected to:
Oracle9i Enterprise Edition Release 9.2.0.7.0 - 64bit Production
With the Partitioning, OLAP and Oracle Data Mining options
JServer Release 9.2.0.7.0 - Production
16:14:11 TEST.SQL>COL FILE_NAME FORMAT A60
16:14:31 TEST.SQL>SELECT FILE_NAME, BYTES/1024/1024 MBYTES FROM DBA_DATA_FILES
16:14:33   2 UNION
16:14:33   3 SELECT 'Total', SUM(BYTES/1024/1024) MBYTES FROM DBA_DATA_FILES
16:14:34   4 /
FILE_NAME                                       MBYTES
SANITIZED                                        11264
SANITIZED                                        11264
SANITIZED                                        11264
SANITIZED                                        11264
SANITIZED                                        11264
SANITIZED                                        11264
SANITIZED                                        11264
SANITIZED                                        15360
SANITIZED                                        15360
SANITIZED                                        15360
SANITIZED                                        15360
SANITIZED                                        15360
SANITIZED                                        15360
SANITIZED                                        15360
SANITIZED                                          512
SANITIZED                                         4096
SANITIZED                                        12288
SANITIZED                                         1024
SANITIZED                                         4096
SANITIZED                                         4096
SANITIZED                                         4096
SANITIZED                                        24576
SANITIZED                                        24576
SANITIZED                                        24576
SANITIZED                                        12288
SANITIZED                                         1024
SANITIZED                                         1024
SANITIZED                                         1024
SANITIZED                                         1500
SANITIZED                                        30000
Total                                           337164
31 rows selected.
Elapsed: 00:00:00.072/ It depends on so many things that's it's almost impossible to give all the ways on the forums. Go to tahiti.oracle.com and browse TFM for the Performance Tuning Guide.
Some pointers:
Queries perf
STATSPACK
TKPROF
Instance Tuning
HTH,
Yoann.

Just explain me in realtime scenario :-)

Hello,
Can any one explain briefly about oracle statistics..
What is mean by statistics and why we are using?
When and how can we use that?
No documents please .....just explain me in realtime scenario :-)
Thanks in Advance
Gobinathan

you are getting boggled and nothing did you read yours previous thread throughly
Reg : DB tuning
Khurram

Differences between 8i and 9i

Hello!
Wonder if somebody could give me a brief description regarding the major advantages with Oracle 9i compared to the 8i database technology. I which areas of the database has there been improvments that I cant live without?
/Afeldt

hi,
i wonder how u put this question!!!!!!!!!!
one of the most important feature amongst so many which appealed me most of all is the multiple block sizes,,
u might know tht anything that can be done to reduce the amount of disk I/O is going to have a positive impact on the throughput of the Oracle database system. and common goal of almost Oracle tuning has the directed and immediate goal of reducing disk I/O. For example, tuning an SQL statement to remove a full table scans makes the query run faster because of the direct reduction in the amount of data blocks that are read from the disk. Adjusting instance tuning parameters such as DB_CACHE_SIZE also has the goal of reducing the amount of disk overhead.
To understand how using multiple block sizes can improve performance of the Oracle database we first have to start by taking a look at the basic nature of disk I/O. Anytime an Oracle data block is accessed from disk, we commonly see three sources of delay. The first and most important source of delay is the read-write head movement time. This is the time required for the read-write head to position itself under the appropriate cylinder. We also see rotational delay as the read-write head waits for the desired block the past beneath it, and the third source of delay is the data transmission time from the disk back to the Oracle SGA.
If we accept the premise that 99 percent of the latency is incurred prior to actually accessing the desired data block, then it makes sense that the marginal cost for reading a 32K block is not significantly greater than the cost of reading a 2K block. In other words, the amount of disk delay is approximately the same regardless of the size of the block. Therefore it should follow that the larger the block that you can read in on a single I/O, the less overall I/O will be performed on the Oracle database.
RAM buffers and Oracle data access Oracle has always provided RAM data buffers to hold incoming data blocks, and data can be read from the buffers 14,000 times faster than reading the data block from disk. The RAM data buffer has evolved from a single buffer in Oracle7 to three data buffers in Oracle8i. These were known as the KEEP pool, the RECYCLE pool, and the DEFAULT pool..
In Oracle9i we still have the three data buffers, but we also have the ability to create a data buffer for every supported blocksize for the Oracle server.
Prior to Oracle9i, Oracle professionals noticed that by moving the entire database to a larger block size, they reduce disk I/O improve the performance of the entire system. This is somewhat counterintuitive, and people ask "if I only need an 80-byte row, where do I get the benefit of reading 16K block?"
hope this would be enough
regards
umar

What is maximum amount of memory that oracle db can utilize ?

Hi
Thank you for reading my post
What is maximum number of memory that oracle database can utilize for each of its memory structure like sga, caches....
Thanks

ps, the following may help too
VLM) Configurations
Oracle Database for Windows supports Very Large Memory (VLM) configurations in Windows 2000, Windows 2003, and Windows XP, which allows Oracle Database to access more than the 4 gigabyte (GB) of RAM traditionally available to Windows applications.
Note:
This feature is available on Windows 2000, Windows 2003, and Windows XP only with Intel Pentium II and above processors.
Specifically, Oracle Database uses Address Windowing Extensions (AWE) built into Windows 2000, Windows 2003, and Windows XP to access more than 4 GB of RAM.
The requirements for taking advantage of this support are:
1. The computer on which Oracle Database is installed must have more than 4 GB of memory.
2. The operating system must be configured to take advantage of Physical Address Extensions (PAE) by adding the /PAE switch in boot.ini. See Microsoft Knowledge Base article Q268363 for instructions on modifying boot.ini to enable PAE.
3. It is advisable (though not necessary) to enable 4GT support by adding the /3GB parameter in boot.ini. See Microsoft Knowledge Base article Q171793 for additional requirements and instructions on modifying boot.ini to enable 4GT.
4. The user account under which Oracle Database runs (typically the LocalSystem account), must have the "Lock memory pages" Windows 2000 and Windows XP privilege.
5. USE_INDIRECT_DATA_BUFFERS=TRUE must be present in the initialization parameter file for the database instance that will use VLM support. If this parameter is not set, then Oracle Database 10g Release 1 (10.1) or later behaves in exactly the same way as previous releases.
6. Initialization parameters DB_BLOCK_BUFFERS and DB_BLOCK_SIZE must be set to values you have chosen for Oracle Database.
Note:
The total number of bytes of database buffers (that is, DB_BLOCK_BUFFERS multiplied by DB_BLOCK_SIZE) is no longer limited to 3 GB.
Dynamic SGA and multiple block size are not supported with VLM. When VLM is enabled, the following new buffer cache parameters are not supported:
o DB_CACHE_SIZE
o DB_2K_CACHE_SIZE
o DB_4K_CACHE_SIZE
o DB_8K_CACHE_SIZE
o DB_16K_CACHE_SIZE
o DB_32K_CACHE_SIZE
To select the block size for the instance, use the initialization parameter DB_BLOCK_SIZE. The buffer cache size is set by the initialization parameter DB_BLOCK_BUFFERS.
7. Registry parameter AWE_WINDOW_MEMORY must be created and set in the appropriate key for your Oracle home. This parameter is specified in bytes and has a default value of 1 GB. AWE_WINDOW_MEMORY tells Oracle Database how much of its 3 GB address space to reserve for mapping in database buffers.
This memory comes from the 3 GB virtual address space in Oracle Database, so its value must be less than 3 GB. Setting this parameter to a large value has the effect of using more of the address space for buffers and using less AWE memory for buffers. However, since accessing AWE buffers is somewhat slower than accessing virtual address space buffers, Oracle recommends that you tune these parameters to be as large as possible without adversely limiting database operations.
In general, the higher AWE_WINDOW_MEMORY is set, the fewer connections and memory allocations will be possible for Oracle Database. The lower AWE_WINDOW_MEMORY is set, the lower the performance.
8. Once this parameter is set, Oracle Database can be started and will function exactly the same as before except that more database buffers are available to the instance. In addition, disk I/O may be reduced because more Oracle Database data blocks can be cached in the System Global Area (SGA).
Note:
Registry parameter VLM_BUFFER_MEMORY, which enabled VLM configurations in earlier releases, is not supported in Oracle Database 10g Release 1 (10.1) or later.
VLM Instance Tuning
VLM configurations improve database performance by caching more database buffers in memory. This reduces disk I/O compared to configurations without VLM. VLM support in Oracle Database 10g Release 1 (10.1) or later has been re-written to integrate very closely with Windows. Compared to Oracle8i release 2 (8.1.6), VLM users should see better performance with the newer implementation.
Tuning for VLM is no different than tuning for configurations without VLM. It is an iterative task that begins by selecting appropriate DB_BLOCK_SIZE and DB_BLOCK_BUFFERS initialization parameters for the application being supported.
Note:
Oracle Database 10g Release 1 (10.1) or later VLM configurations do not support multiple database block sizes.
AWE_WINDOW_MEMORY, a new registry parameter specific to VLM, tells Oracle Database how much of its address space to reserve for mapping in database buffers. It defaults to a value of 1 GB, which should be suitable for most installations. If DB_BLOCK_SIZE is large, however, the default AWE_WINDOW_MEMORY value of 1 GB may not be sufficient to start the database.
Increasing the value of AWE_WINDOW_MEMORY will improve performance, but it will also limit the amount of memory available for other Oracle Database threads (like foreground threads). Clients may see "out of memory" errors if this value is set too large. As a general guideline, increase the AWE_WINDOW_MEMORY registry value by 20 percent.
For example, if DB_BLOCK_SIZE is set to 8 KB, AWE_WINDOW_MEMORY is set to 1 GB, and the number of LRU latches is set to 32 (16 processor computer), then database startup fails with out of memory errors 27102 and 34. Increasing the value of AWE_WINDOW_MEMORY to 1.2 GB fixes the problem.
Having a large cache in a VLM configuration may also slow down database writer (DBWR) threads. Having more DBWR threads will distribute work required to identify and write buffers to disk and will distribute I/O loads among threads. Initialization parameter DB_WRITER_PROCESSES enables you to configure multiple database writer threads.
A large cache can also introduce contention on the LRU (least recently used) latch. On symmetric multiprocessor (SMP) systems, Oracle Database sets the number of LRU latches to a value equal to one half the number of processors on the system. You can reduce contention on such configurations by increasing the number of LRU latches to twice (or four times) the number of processors on the system.
See Also:
Oracle Database Performance Tuning Guide for more information on instance tuning
Windows 4 GB RAM Tuning (4GT)
The following Windows operating systems include a feature called 4 GB RAM Tuning (4GT):
· Windows Server 2003
· Windows 2000 Advanced Server
· Windows 2000 Datacenter Server
This feature allows memory-intensive applications running on Oracle Database Enterprise Edition to access up to 3 GB of memory, as opposed to the standard 2 GB in previous operating system versions. 4GT provides a tremendous benefit: 50 percent more memory is available for database use, increasing SGA sizes or connection counts.
Large User Populations
Several features allow Oracle Database to support an increasingly large number of database connections on Windows:
· Oracle Database Shared Server Process, which limits the number of threads needed in the Oracle Database process, supports over 10,000 simultaneous connections to a single database instance.
· Oracle Net multiplexing and connection pooling features allow a large configuration to connect more users to a single database instance.
· Oracle Real Application Clusters raises connection counts dramatically by allowing multiple server computers to access the same database files, increasing the number of user connections by tens of thousands, as well as increasing throughput.
rgds
alan

High Consistent Gets and memory settings

What is actually high consistent gets?
I get High Consistent Gets for certain sessions. Following are some of my parameter settings.
db_16k_cache_size = 0
db_2k_cache_size = 0
db_32k_cache_size = 0
db_4k_cache_size = 0
db_8k_cache_size = 0
db_block_size = 8192
sga_max_size = 7632M
sga_target = 7632M
shared_pool_reserved_size = 119957094
shared_pool_size = 48M
pga_aggregate_target = 1500M
Will setting AMM by configuring following parameter help Oracle to manage the memory in terms of workload and reduce CONSISTENT GETS?
Or do I need to manually configure parameter such as "db_8k_cache_size".?
memory_max_target = my SGA+PGA: 9.5G
memory_target = my SGA+PGA: 9.5G
sga_target = 0
pga_agreegate_target =0
Regards, Lily

Lily wrote:
What is actually high consistent gets?These are the logical IO's . If the logical IOs are high, it may mean that you have selected a lot of data which is now supposed to be given back to you. The high Logical IOs is not something that you should try to minimize using a high amount of memory since its already cached data. That sort of workaround works or would work if the physical IOs are high. If the session is doing more logical IO's check the query and the selectivity of the data and see if you can limit it further.
I get High Consistent Gets for certain sessions. Following are some of my parameter settings.
db_16k_cache_size = 0
db_2k_cache_size = 0
db_32k_cache_size = 0
db_4k_cache_size = 0
db_8k_cache_size = 0
db_block_size = 8192
sga_max_size = 7632M
sga_target = 7632M
shared_pool_reserved_size = 119957094
shared_pool_size = 48M
pga_aggregate_target = 1500M
Will setting AMM by configuring following parameter help Oracle to manage the memory in terms of workload and reduce CONSISTENT GETS?
Or do I need to manually configure parameter such as "db_8k_cache_size".?
memory_max_target = my SGA+PGA: 9.5G
memory_target = my SGA+PGA: 9.5G
sga_target = 0
pga_agreegate_target =0
As I said, instance tuning is not something that you should aim for .
Aman....

Reg Instance Tuning

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