Oracle 9i rac cache fusion queries

Hi RAC experts,
Would like to understand more on the background of cache fusion.
Kindly advise on the following cache fusion operation as i'm having some confusion.
1. read/read - user on node 1 wants to read a block that user on node 2 has recently read.
in this case, the block is already on the cache of node 2 since it is recently read. so does node 1 read from disk to store in it's down cache since the info is not in it's cache? or it can request directly from the remote cache in node 2 to do shipping of the block to it's own cache for select?
2. read/write - user on node 1 want to read a block that user on node 2 has recently updated.
in this case, node one will get the recently updated info from remote cache(node 2) to it's local cache for update right?
3) write/read - user on node 1 want to update a block that user on node 2 has recently read.
does node 1 read from disk since the info is not in it's cache? or it can request directly from the remote cache in node 2 to do shipping of the block to it's own cache for update?
thanks
junior dba

1. read/read - user on node 1 wants to read a block that user on node 2 has recently read.Since the block is in another instance's buffer cache, the questing instance(1 in your case) will request the block to be shipped from node 2. It will avoid going to disk.
.2. read/write - user on node 1 want to read a block that user on node 2 has recently updated.in this case, node one will get the recently updated info from remote cache(node 2) to it's local cache for update right?
That's correct.
oes node 1 read from disk since the info is not in it's cache? or it can request directly from the remote cache in node 2 to do shipping of the block to it's own cache for update?Same as in 1) above, it gets from the other's instance.
These concepts have been explained well in RAC Handbook by K Gopalakrishnan. Here is the additional information on the book. http://www.amazon.com/Database-Application-Clusters-Handbook-Osborne/dp/007146509X/ref=pd_bbs_sr_1?ie=UTF8&s=books&qid=1211888392&sr=8-1
HTH
Thanks
-Chandra

Similar Messages

Oracle RAC Cache Fusion , Insert intensive tables.

Hi,
I have one general questions in RAC cache fusion. It was observed that there are too much interinstance contention as the insert intensive queries are executed. What is the best possible solution to solve this. I mean how to avoid the contention. Is there any general approach.
Thanking you
Rocky

As others have pointed out, the first step would be to determine what object or objects was actually causing contention.
If we're talking about a hypothetical OLTP application with 400 concurrent users on 2 nodes of a RAC cluster, inserting into a heap-organized table with no bitmap indexes I would wager that the most likely cause of contention would be contention for index blocks on monotonically increasing columns (i.e. sequence-generated primary keys). Since indexes are sorted structures, the next row will almost always be going into the right-most block of the index. If both nodes are fighting over who has that right-most block at any instant, that can cause lots of contention as the block gets moved back and forth between the nodes. If you don't need to do range scans on the index, the solution would be to change the primary key index to be a reverse key index so that inserts are spread across a larger number of index blocks at any instant. Of course, this is just one possible scenario-- there are dozens if not hundreds or thousands of possible permutations. It comes down to figuring out what resource the various sessions are contending on and then figuring out how to reduce that contention without screwing up anything else too badly.
Justin
Edited by: Justin Cave on Jun 19, 2009 12:50 AM

RAC Cache Fusion

Hello,
RAC databases have multiple instances. Here we assume there are two nodes (Node A and Node B).
If suppose node A reads data block (abc) from disk and update it as "xyz" but not committed. At the same time node B wants to read the same data block. So here comes cache fusion technology which transfers data "xyz" from node A instance to node B instance through inter connect mechanism.
My doubt is since the changed data is not been committed in node A then how node B can view the data "xyz"? Only the old image should be transferred to node B.
Is my understanding is correct? Any one can explain this.
Thanks
Gokul

hi,
hope this helps
http://advait.wordpress.com/2008/07/21/oracle-rac-10g-cache-fusion/
regards,
Deepak

Disable RAC Cache Fusion in 10r2

Hi all,
is it possible to disable the Oracle Cache Fusion in Oracle Database 10.2.0.4 Database ?
Regards,

I think it is nonsense to think about disabling cache fusion. and it is almost not possible. On the other hand, how can RAC work without this feature ? How can you imagine the work of your RAC system without global synchronization between nodes ???
Regarding to singleton concept which is mentioned by guys, it means that the idea here is concentrating the database service which your application uses on one node, so mostly your application will be served by this node, which means the roundtrip between instances will be low. You can think about this state just like you are working with single instance database, as here cache synchronization overhead is almost eliminated. Basically RAC itself also does remastering of resources, based on workload dynamically, but remember that if your database service is served by several instances, your connections could be directed to both of them and in inpredictable fashion, based on load balansing goal to be exact.
Besides all of this, there are several wait event classes spesific for RAC and corresponding views for them. you can explore them and find the idea about which wait classes are bottleneck.

[RAC] 9I REAL APPLICATION CLUSTERS의 CACHE FUSION 에 대한 이해

제품 : ORACLE SERVER
작성날짜 : 2004-08-13
[RAC] 9I REAL APPLICATION CLUSTERS의 CACHE FUSION 에 대한 이해
==========================================================
PURPOSE
이 문서는, 오라클 리얼 애플리케이션 클러스터 환경의 캐쉬 퓨전의 기능과 장점을
설명하는 것을 목적을 한다.
SCOPE
Real Application Clusters(RAC) Option은 9i Standard Edition에서는
지원하지 않는다.
Explanation
Oracle 8i OPS에서 캐쉬 퓨전의 개념이 소개 되었다. 이 기능은, 원격 인스턴스가 관장하는
블럭에 대한 읽기 일관성 있는 뷰를 위해 디스크를 통한 블럭의 pinging을 감소 시키는 목적으로
추가되었다. 이 기능은, 다른 인스턴스에 의해 lock이 걸린 데이터를 select하는데 필요한 시간을
현격하게 감소 시켜 주었다.
lock을 건 인스턴스가 변경 사항을 기록하도록 강제 하여 (I/O 발생을 강제 발생) 원격 인스턴스가
읽을 수 있게 하는 대신, 캐쉬 퓨전은 버퍼의 사본을 생성하여, 노드간 고속 연결 라인을 통해
데이터를 조회하는 측에 전달 시켜준다. 이 개념은, 읽기/쓰기 경합에 따른 성능상의 문제를
경감시켜 주기는 하나, 블럭의 내용을 변경시켜야 한다면, 원격 인스턴스에서 해당 블럭에 대해 쓰기를
하도록 한 후 읽어 들여 사용하는 기존 방식과 동일한 ping 메카니즘을 사용 해야 했다.
9i 리얼 애플리케이션 클러스터에서는, 쓰기/쓰기 경합 문제를 해결할 수 있도록 캐쉬 퓨전이
설계되었으므로, 성능 향상 및 확장성이 개선 되었다. RAC cache fusion을 통해 Oracle 에서는
다른 인스턴스에서 lock이 걸린 블럭에 대해 디스크를 통한 'ping'이 개념상으로는 더이상
발생하지 않도록 함으로써, I/O의 양을 더 줄여 주게 되었다. 대신 RAC 인스턴스는, 더티
버퍼의 사본에 대해 원격 인스턴스에서 쓰기 권한을 가질 수 있게 해 주었다. 이 기능은
dba (1:1) 를 사용하는 realesable locking (특정 데이터 파일에 gc_files_to_locks 값을
0으로 지정하거나, gc_files_to_locks 값을 아예 설정하지 않을 경우 사용 가능) 에서만
적용되는 기능이다. Hashed lck은 ping 메카니즘을 이전 방식과 동일하게 사용하며, fixed lock은
9i RAC에서는 더이상 사용 할 수 없게 되었다. (잇점이 없기에)
앞에서 언급한 바와 같이 RAC 캐쉬 퓨전에서는 인스턴스가 dirty buffer의 사본을 사용할 수 있게
해 준다. RAC 캐쉬 퓨전에서 새로 등장한 개념은 past image라는 개념인데 이것은 버퍼의 이전
사본이 디스크게 기록되지 않은 상태를 말한다. 이 past image를 추적하기 위해 오라클에서는 전역
락과 로컬 락의 role과 BWR (block written redo)를 사용한다. global 과 local lock의 role을 명확히
하기 위해 Oracle 8i의 lock을 local lock으로 생각해보자. 이 경우 오라클 8i에서는 3가지 종류의
락 모드가 존재한다 :
N - Null
S - Shared
X - Exclusive
오라클 9i RAC의 lock모드를 언급할 때는 3 글자로 lock의 종류를 구분한다. 첫번째 글자는 lock mode를
나타내고, 두번째 글자는 lock의 role, 세번째 글자는 (숫자) 로컬 인스턴스에 past image가 있는지
여부를 나타낸다. 이와 같은 방식으로 lock의 종류는 다음과 같이 나타낼 수 있다 :
NL0 - Null Local 0 - 8i의 N과 동일 (past image 없음)
SL0 - Shared Local 0 - 8i의 S와 동일 (past image 없음)
XL0 - Exclusive Local 0 - 8i의 X와 동일 (past image 없음)
SG0 - Shared Global 0 - 글로벌 S 락, 인스턴스에 current block image 소유
XG0 - Exclusive Global 0 - 글로벌 X 락, 인스턴스에서 current block image 소유
NG1 - Null Global 1 - 글로벌 N 락, 인스턴스에서 past image 소유
SG1 - Shared Global 1 - 글로벌 S 락, 인스턴스에서 past image 소유
XG1 - Exclusive Global 1 - 글로벌 X 락, 인스턴스에서 past image 소유
lock이 최초로 획득된 경우, 로컬 role로 획득된다.만약 lock이 획득된 시점에 원격 인스턴스에 더티
버퍼가 존재한다면, 글로벌 락 role을 가지고 획득하며, 이 경우, 더티 버퍼를 모든 원격 인스턴스에서는
버퍼의 'past image'로 취급한다. 리커버리를 위해 past image를 가지고 있는 인스턴스에서는
lock을 점유하고 있는 마스터 인스턴스에서 lock을 해재했다고 알려 오기 전 까지는 past image를
버퍼 캐쉬에 저장한다. 버퍼내의 블럭이 폐기 될 때는 past image를 관리하는 인스턴스에서 DBR
또는'block written redo'를 redo 스트림에 기록하게 되는데 이것은, 블럭이 이미 디스크에
기록되었으므로, 이 인스턴스를 recovery하는데는 필요하지 않다는 것을 나타낸다.
RAC 클러스터의 3번 노드가 EMP 테이블의 블럭을 관장하는 락 엘리먼트 123을 소유하고 있다고
가정해 보자 :
사용자 C가 인스턴스 3에 연결된 상태에서 EMP 테이블에 대한 select를 하면서 SL0 락이
오픈 되었다 :
| Instance 1 | | Instance 2 | | Instance 3 |
| | | | | |
| Lock Held | | Lock Held: | | Lock Held: |
| on LENUM 123: | | on LENUM 123: | | on LENUM 123: |
| | | | | SL0 |
| | | | | |
Shared lock을 획득하는 것은 락 role에 아무런 영향을 미치지 않는다. 따라서 만약 인스턴스
2번에 연결된 사용자 B가 동일한 EMP 테이블에 대해 select를 하더라도, 인스턴스 2의 락
엘리먼트 123의 락 모드는 동일하다. ( S 락이기 때문임 ) 그리고 락의 role 또한 동일한데
버퍼 내용에 더티 상태로 변경된 내용이 없기 때문이다 :
| Instance 1 | | Instance 2 | | Instance 3 |
| | | | | |
| Lock Held | | Lock Held | | Lock Held |
| on LENUM 123: | | on LENUM 123: | | on LENUM 123: |
| | | SL0 | | SL0 |
| | | | | |
첫번째 exclusive 락을 획득하는 것은 락의 role에 영향을 미치지 않는데 이 경우에도
락 엘리먼트에 대한 더티 버퍼가 없기 때문이다. 따라서 만약 사용자 B가 EMP 테이블의 락
엘리먼트 123에 속하는 row를 update 하더라도, XL0이 획득되고, 이미 획득된
SL0 락은 제거된다. 이것은 8i OPS와 동일한 동작이다.
| Instance 1 | | Instance 2 | | Instance 3 |
| | | | | |
| Lock Held | | Lock Held | | Lock Held |
| on LENUM 123: | | on LENUM 123: | | on LENUM 123: |
| | | XL0 | | |
| | | | | |
원격 노드상에 더티 버퍼가 존재하는 락 에리먼트에 대해 exclusive 락을 회극하는 것은 캐쉬
퓨전에서 2단계로 넘어가도록 한다. 이 경우 인스턴스 1번에 연결된 사용자 A가
락 엘리먼트 123번에 속하는 EMP 테이블의 row를 update 할 때, 인스턴스 2번의 블럭은
버퍼 캐쉬 내에서 더티 상태로 존재하므로, 인스턴스는 블럭에 대한 사본을 생성 하여 인스턴스
1번에 전달 한 후, 인스턴스는 null 글로벌 락을 같는다 (page image)*. 동시에
인스턴스 1은 exclusive, globally dirtied lock을 획득하며, 인스턴스 2는 past
image를 유지한다.
* 인스턴스에서 블럭에 대한 자신만의 page image를 갖는 것은, 블럭이 디스크에 게록되지 않고
또, 마스터 노드에서 알려주기 전 까지는 이미지를 폐기 하지 않기 위해서이다.
| Instance 1 | | Instance 2 | | Instance 3 |
| | | | | |
| Lock Held | | Lock Held | | Lock Held |
| on LENUM 123: | | on LENUM 123: | | on LENUM 123: |
| XG0 | | NG1 | | |
| | | | | |
이제 인스턴스 3에 연결된 사용자 C가 EMP 테이블을 select 하려고 하며, EMP 테이블이
락 엘리먼트 123에 속해있는 경우를 살펴보자. 사용자 C가 select 명령을 수행 시키면
인스턴스 1의 락은, S 락으로 하향 조정되며, 가장 최근의 buffer 내 사본을 갖고 있으며
인스턴스 2번은 그 이전의 버퍼에 대한 past image를 유지하게 된다.
| Instance 1 | | Instance 2 | | Instance 3 |
| | | | | |
| Lock Held | | Lock Held | | Lock Held |
| on LENUM 123: | | on LENUM 123: | | on LENUM 123: |
| SG1 | | NG1 | | SG0 |
| | | | | |
이제 인스턴스 2번의 사용자 B가 EMP 락 엘리먼트 123에 대해 select를 하는 경우를 가정해
보자. 인트넛느 2는 다른 인스턴스로 부터 읽기 일관성 있는 버퍼의 사본을 요청하게 된다.
인스턴스 2번에 버퍼 내용을 전달해 줄 인스턴스는 다음과 같은 순서에 의해 결정된다:
1. lock에 대한 마스터 인스턴스.
2. 가장 최후의 page image를 S lock으로 점유하고 있는 인스턴스.
3. Shared local 상태로 lock을 점유한 인스턴스.
4. 가장 최근에 S lock를 부여 받은 인스턴스.
인스턴스 1번이 락에 대한 마스터 인스턴스라고 가정해 보자 ( 그리고 가장 최근의 past image를 소유 )
이 경우 인스턴스 2는 인스턴스 1번의 버퍼 캐쉬에 저장된 블럭 사본을 전달 받고, 인스턴스 2번이
SG1 (past image에 대한 일기 일관성을 갖춘 사본) lock을 획득한다. 나머지 노드는 동일한 상태가
유지된다:
| Instance 1 | | Instance 2 | | Instance 3 |
| | | | | |
| Lock Held | | Lock Held | | Lock Held |
| on LENUM 123: | | on LENUM 123: | | on LENUM 123: |
| SG1 | | SG1 | | SG0 |
| | | | | |
이제 인스턴스 3번에 연결된 사용자 C가 테이블의 락 엘리먼트 123의 row를 upate 하고자 한다고
가정해 보자. 사용자 C는 exclusive lock을 요청하며, 인스턴스 1번과 2번은 소유하고 있던 lock이
하향 조정된다. 결과적으로는 인스턴스 3번이 XG0 lock을 점유하게 되고 인스턴스 1, 2번은
NG1을 각각 점유 하게 된다:
| Instance 1 | | Instance 2 | | Instance 3 |
| | | | | |
| Lock Held | | Lock Held | | Lock Held |
| on LENUM 123: | | on LENUM 123: | | on LENUM 123: |
| NG1 | | NG1 | | XG0 |
| | | | | |
인스턴스 3번에서 체크 포인트가 발생하는 경우, 모든 더티 버퍼의 내용을 디스크에 기록하게 된다.
이 때 인스턴스 3은 마스터노드가 기록을 하였음을 다른 노드에게 알려주게 된다. 이 경우 인스턴스
1, 2번은 past image를 폐기 처분할 수 있게 되며 인스턴스 3번만 XL0 락을 점유하게 된다.
유의해야 할 점은 인스턴스 1, 2가 BWR(block written redos)을 각각의 리두 스트림에 기록하여
해당 블럭이 이미 디스크에 기록되었으며, 인스턴스 리커버리에는 필요하지 않음을 기록한다는 점이다.
| Instance 1 | | Instance 2 | | Instance 3 |
| | | | | |
| Lock Held | | Lock Held | | Lock Held |
| on LENUM 123: | | on LENUM 123: | | on LENUM 123: |
| | | | | XL0 |
| | | | | |
Example
Reference Documents
Note:139436.1 - Understanding 9i Real Application Clusters Cache Fusion
Note 144152.1 - Understanding 9i Real Application Clusters Cache Fusion Recovery
Note 139435.1 - Fast Reconfiguration in 9i Real Application Clusters

Hi, how are you ?
Well, Oracle8i greatly improved scalability for read/write applications through the introduction of Cache Fusion. Oracle9i improved Cache Fusion for write/write applications by further minimizing much of the disk write activity used to control data locking.
It�s this.
If you still having doubt, please call me.
Regina Vidal

Enable Cache Fusion in Oracle RAC

Hi gurus,
I cannot find on google how to enable and test Cache Fusion feautre in Oracle RAC. Could you help me please?
Best.

I don't know. I cannot find parameter which enable or disable CFAs Aman has already stated the feature is already present
http://download.oracle.com/docs/cd/B28359_01/server.111/b28318/consist.htm#CNCPT1317
I even cannot find information how to test CF to ensure that it really works?!http://download.oracle.com/docs/cd/B28359_01/rac.111/b28254/monitor.htm#RACAD981
@Aman
Cache Fusion is the technology which makes the 10g RAC, 10g RAC. And 11g Database as well :)
Edited by: Amy De Caj on Jul 19, 2009 4:26 AM
Edited by: Amy De Caj on Jul 19, 2009 4:28 AM

Oracle 10g RAC on Windows

Installed Oracle 10g RAC on Windows... Everything was
working fine, now when I install CRS it completed at 100% and then in the configuration it gives error
INFO: exitonly tools to be excuted passed: 0
INFO: Starting to execute configuration assistants
INFO: Command = C:\WINDOWS\system32\cmd /c call C:\oracle\product\10.2.0\crs/install/crssetup.config.bat
PROT-1: Failed to initialize ocrconfig
Step 1: checking status of CRS cluster
Step 2: creating directories (C:\oracle\product\10.2.0\crs)
Step 3: configuring OCR repository
ocr upgrade failed with (-1)
Execution of the plugin was aborted
INFO: Configuration assistant "Oracle Clusterware Configuration Assistant" was canceled.
*** Starting OUICA ***
Oracle Home set to C:\oracle\product\10.2.0\crs
Configuration directory is set to C:\oracle\product\10.2.0\crs\cfgtoollogs. All xml files under the directory will be processed
INFO: The "C:\oracle\product\10.2.0\crs\cfgtoollogs/configToolFailedCommands" script contains all commands that failed, were skipped or were cancelled. This file may be used to run these configuration assistants outside of OUI. Note that you may have to update this script with passwords (if any) before executing the same.
I am using VMware WorkStation 5
http://www.oracle-base.com/articles/10g/OracleDB10gR2RACInstallationOnWindows2003UsingVMware.php
I can see my disks from both machines. Open the "Computer Management" dialog (Start > All Programs > Administrative Tools > Computer Management
I use Windows XP SP2 as the host operating system
Any suggestion?
Message was edited by:
MEXMAN

You know its not certified?
My first thought when I read the subject of this thread, and before reading what you posted, is that you've either done no research on RAC or didn't understand what you've read.
You can create a RAC cluster using any operating system certified by Oracle.
But the operating system is the least important part of creating a cluster. The questions you need to be able to address are:
1. What is your solution to created shared storage?
2. What is your solution to create the cache fusion interconnect and VIPs?
If you don't have an answer to these questions you can not build a RAC cluster.

Oracle 10g RAC on solaris 10 installation

hi
i want to know the default file location of following:
oracle base
oracle home
control files
redo log files
data files
plz tell me exactly the default path for all the above

I'm assuming you mean running RAC with or without Sun Cluster? If so, the answer is that there would almost no difference in most cases. The only case I can think of would be if you had a sub-optimal interconnect without Sun Cluster where Sun Cluster's clprivnet would have given you striping and availability for free.
I am currently working on a Blueprint that describes the important differences between the two configurations (with and without SC). They can broadly be summarised as:
Sun Cluster gives you:
* Better data integrity protection
* Faster, more reliable node failure detection
* Makes your name space homogeneous, simplifying installation and device management (DID structure), so no need for messy symbolic links
* Gives you a highly available, striped cluster interconnect for the Cache Fusion traffic. (No need for tricky IPMP or link aggregation configurations.)
* Allows you to use volume managers link Solaris Volume Manager or VxVM
* Provides support for shared QFS as a file system for all Oracle objects, data includes (while still allowing ASM)
* A substantial collection of Sun written and supported agents to manage other applications you might also have on your cluster, e.g. NFS, SAP, Apache, etc, etc.
Hope that helps,
Tim
---

Oracle Database RAC 11gR2 : Role of Public,Private,Virtual, and SCAN IPs.

Hi Experts,
1. Can you please let me know why do we need configure below IP addresses for RAC setup and what is the role that each one plays ?
- Public
- Private
- Virtual
-SCAN
2. What is the relationship between SCAN IP and Virtual IPs ?
Regards

Hi,
859875 wrote:
Hi Experts,
1. Can you please let me know why do we need configure below IP addresses for RAC setup and what is the role that each one plays ?
- PublicConfigured before installation for each node, and resolvable to that node before installation.
Role:
Allow communication/configuration of Virtual/SCAN between the nodes of the cluster. Without Public Interface/IP the Clusterware don't start.
The Virtual/SCAN will work as alias IP on Public Interface over Public Network.
- Private or InterconnectConfigured before installation, but on a separate, private network, with its own subnet, that is not resolvable except by other cluster member nodes
Role:
Clusterware uses the interconnect for cluster synchronization (network heartbeat) and daemon communication between the the clustered nodes.
RAC uses the interconnect for cache fusion (UDP) and inter-process communication (TCP).
Cache Fusion is the remote memory mapping of Oracle buffers, shared between the caches of participating nodes in the cluster.
- VirtualConfigured before installation for each node, but not currently in use. On the same subnet as all other public IP addresses, VIP addresses, and SCAN addresses.
Role:
The goal is application availability. If add or remove nodes it's necessary make config your client adding/removing VIP (with SCAN it's not necessary)
When a node fails, the VIP associated with it is automatically failed over to some other node.
Without using VIPs or FAN, clients connected to a node that died will often wait for a TCP timeout period (which can be up to 10 min) before getting an error.
As a result, you don't really have a good HA solution without using VIPs and FAN. The easiest way to use FAN is to use an integrated client with Fast Connection Failover (FCF) such as JDBC, OCI, or ODP.NET.
-SCANThree Static IP addresses configured on the domain name server (DNS) before installation so that the three IP addresses are associated with the name provided as the SCAN, and all three addresses are returned in random order by the DNS to the requestor
Configured before installation in the DNS to resolve to addresses that are not currently in use. On the same subnet as all other public IP addresses, VIP addresses, and SCAN addresses
Role:
The goal is application availability before clients establish communication with RAC and make the Cluster-Wide totally transparent.
SCAN IP is a new "layer" network (oracle) with high availability that allows you to change the characteristics of your cluster (i.e add/remove nodes) without the need to make configuration changes in their clients "Grid concept".
>
2. What is the relationship between SCAN IP and Virtual IPs ?SCAN IP is used to receive new connection requests and redirects to the VIP IP.
The Virtual IP establishes and allow failover of the connections after connection being established.
When the client requests a connection, Oracle Client 11gR2 find for IPs available for this host-scan and create a list of all SCAN IP the first connection attempt on RAC is using one of SCAN IPs avaliable.
The SCAN Listener will receive this connection and re-direct to one of avaliable nodes using LOCAL_LISTENER from this point the the connection is established using Virtual IP (VIP).
All SCAN/VIP must be resolved by DNS.
The client knows that there is only the SCAN Hostname, which is configured in the connection string.
Once the connection is requested Oracle Clusterware redirects the connection to one of the VIP hostname which must be resolved by DNS.
Regards,
Levi Pereira

Oracle 11g result cache and TimesTen

Oracle 11g has introduced the concept of result cache whereby the result set of frequently executed queries are stored in cache and used later when other users request the same query. This is different from caching the data blocks and exceuting the query over and over again.
Tom Kyte calls this just-in-time materialized view whereby the results are dynamically evaluated without DBA intervention
http://www.oracle.com/technology/oramag/oracle/07-sep/o57asktom.html
My point is that in view of utilities like result_cache and possible use of Solid State Disks in Oracle to speed up physical I/O etc is there any need for a product like TimesTen? It sounds to me that it may just asdd another layer of complexity?

Oracle result cache ia a useful tool but it is distinctly different from TimesTen. My understanding of Oracle's result cache is caching results set for seldom changing data like look up tables (currencies ID/code), reference data that does not change often (list of counter parties) etc. It would be pointless for caching result set where the underlying data changes frequently.
There is also another argument for SQL result cache in that if you are hitting high on your use of CPUs and you have enough of memory then you can cache some of the results set thus saving on your CPU cycles.
Considering the arguments about hard wired RDBMS and Solid State Disks (SSD), we can talk about it all day but having SSD does not eliminate the optimiser consideration for physical I/O. A table scan is a table scan whether data resides on SCSI or SSD disk. SSD will be faster but we are still performing physical IOs.
With regard to TimesTen, the product positioning is different. TimesTen is closer to middletier than Oracle. It is designed to work closely to application layer whereas Oracle has much wider purpose. For real time response and moderate volumes there is no way one can substitue TimesTen with any hard wired RDBMS. The request for result cache has been around for sometime. In areas like program trading and market data where the underlying data changes rapidly, TimesTen will come very handy as the data is real time/transient and the calculations have to be done almost realtime, with least complications from the execution engine. I fail to see how one can deploy result cache in this scenario. Because of the underlying change of data, Oracle will be forced to calculate the queries almost everytime and the result cache will be just wasted.
Hope this helps,
Mich

Oracle 10g RAC installation on HP-UX 11.31 for SAP ERP 6.04

Dear experts,
We are trying to install SAP ERP 6.0 EHP4 with Oracle 10g RAC on HP-UX 11.31. Please note that, We are using VERITAS cluster filesystem (CFS) for this purpose and not HP-UX ServiceGuard ClusterFileSystem.
*As per SAP procedure, we have installaed plain plain SAP system with single instance Oracle (ref: Configuration of SAP NetWeaver for Oracle Database 10gRAC guide). Now we are first trying to install Oracle Clusterware (CRS) and then we will install Oracle RAC software. Is this procedure right?*
Which file (and its path) we have to use for CRS installation and its patch? Is it runInstaller under /oracle/stage/102_64/clusterware? With this file we can install CRS 10.2.0.1. Similarly for Oracle RAC, which files we are supposed to use, i.e for installation and patch upgrade?
Also can we use clusterware package available from Oracle directly in the SAP environment?
We tried to install CRS with runInstaller while running Configuration Assistant after root.sh script.
The following commands are failing in Configuration Assistant:
/oracle/CRS/102_64/bin/racgons add_config erpprdd1:4948 erpprdd2:4948
/oracle/CRS/102_64/bin/oifcfg setif -global lan1/20.20.20.0:cluster_interconnect lan0/192.168.3.0:public
/oracle/CRS/102_64/bin/cluvfy stage -post crsinst -n erpprdd1,erpprdd2
1st command does not give any output if run manually.
2nd commands o/p: PRIF-12: failed to initialize cluster support services
3rd commands fails in every check
Please suggest the solution and expecting answers to the above mentioned questions.
Thanks & Regards,
Tejas

>
Charles Yu wrote:
> Q1: Oracle RAC with 9.2.x on HP-UX?
> A: For HA environment, cluster software is: MC/SG on HP-UX 11.31; there are optional components of MC/SG for supporting Oracle RAC and SAP application. I was confused that I could not find the installation guide regarding 4.6C on MC/SG HA environment of HP-UX.
> Charles
Relevant docs for Service Guard (SG) cluster are available at http://docs.hp.com. Hope you have checked for the suport of oracle 92x on HP-UX 11.31
>
Charles Yu wrote:
> Q2: Any reason why you don't use a supported database version?
> A: Actually, in order to avoiding the the risk of database upgrade and minimizing the migration risk, top level has decided that keeping the same Oracle version. Indeed, we don't plan the migration of application. On the other hand, it is complicated to do the assessment for application migration.
> Charles
You can go for combined os migration and db release upgrade also at a stretch with the same downtime.

Oracle.apps.fnd.cache.CacheException while generating Auto Reports

Hi,
Please help me in resolving out the ERROR occured while dealing with Automated Report Generation.
Following is the Error Message:
Weekly Report Generator starts running at:Tue Jun 24 14:41:47 IST 2008
connection oracle.jdbc.driver.T4CConnection@789144
Generating Health Summary Report for: _11_5_1.html
oracle.apps.fnd.cache.CacheException
at oracle.apps.fnd.cache.AppsCache.get(AppsCache.java:228)
at oracle.apps.fnd.profiles.Profiles.getProfileOption(Profiles.java:1485)
at oracle.apps.fnd.profiles.Profiles.getProfile(Profiles.java:354)
at oracle.apps.fnd.profiles.ExtendedProfileStore.getSpecificProfileFromDB(ExtendedProfileStore.java:210)
at oracle.apps.fnd.profiles.ExtendedProfileStore.getSpecificProfile(ExtendedProfileStore.java:169)
at oracle.apps.fnd.profiles.ExtendedProfileStore.getProfile(ExtendedProfileStore.java:148)
at oracle.apps.fnd.common.logging.DebugEventManager.configureUsingDataba
seValues(DebugEventManager.java:1149)
at oracle.apps.fnd.common.logging.DebugEventManager.configureLogging(Deb
ugEventManager.java:1010)
at oracle.apps.fnd.common.logging.DebugEventManager.internalReinit(Debug
EventManager.java:979)
at oracle.apps.fnd.common.logging.DebugEventManager.reInitialize(DebugEv
entManager.java:946)
at oracle.apps.fnd.common.logging.DebugEventManager.reInitialize(DebugEv
entManager.java:933)
at oracle.apps.fnd.common.AppsLog.reInitialize(AppsLog.java:570)
at oracle.apps.fnd.common.AppsContext.initLog(AppsContext.java:932)
at oracle.apps.fnd.common.AppsContext.initializeContext(AppsContext.java
:917)
at oracle.apps.fnd.common.AppsContext.initializeContext(AppsContext.java
:882)
at oracle.apps.fnd.common.AppsContext.<init>(AppsContext.java:742)
at oracle.apps.fnd.common.WebAppsContext.<init>(WebAppsContext.java:933)
at uttara.oracle.apps.uttaraimc.reports.jasper.HealthSummaryReportGenera
tor.getServiceApplicationModule(HealthSummaryReportGenerator.java:110)
at uttara.oracle.apps.uttaraimc.reports.jasper.HealthSummaryReportGenera
tor.generateReport(HealthSummaryReportGenerator.java:40)
at uttara.oracle.apps.uttaraimc.reports.jasper.WeeklyReportGenerator.gen
erateWeeklyReports(WeeklyReportGenerator.java:75)
at uttara.oracle.apps.uttaraimc.reports.jasper.WeeklyReportGenerator.mai
n(WeeklyReportGenerator.java:27)
Caused by: oracle.apps.jtf.base.resources.FrameworkException: Error in IAS Cache
: java.lang.NullPointerException: null Connection
at oracle.apps.jtf.cache.IASCacheProvider.get(IASCacheProvider.java:678)
at oracle.apps.jtf.cache.CacheManager.getInternal(CacheManager.java:4684)
at oracle.apps.jtf.cache.CacheManager.get(CacheManager.java:4507)
at oracle.apps.fnd.cache.AppsCache.get(AppsCache.java:216)
... 20 more
Error: Report cannot be created at: /oracle10/oracle/viscomn/java/oracle/apps/me
dia/CDV/CDVReport/HTML/Auto/Weekly/24_06_2008/ status: false
Error:oracle.apps.fnd.cache.CacheException
No. of reports generated:0
************************************************************************

It looks like the reports to be created is trying to use
/oracle10/oracle/viscomn/java/oracle/apps/media/CDV/CDVReport/HTML/Auto/Weekly/24_06_2008/
And it can not write in that location. Specify a different folder or check the permisisons/free space avaialable.
Rajesh Alex

How to configure Oracle 10g RAC on windown sever 2003

hi all
plz tell me
how to configure Oracle 10g RAC on windown sever 2003 can any body help me , give be any link
plz it is very necessary for me
Regards

Hello,
There are a good doc written by Philip Newlan at www.jobcestbon.com/oracle/RacOnWindows.pdf
Regards,
Rodrigo Mufalani
http://mufalani.blogspot.com

Oracle 10g rac installation on IBM power server

Dear Gurus,
I am installing Oracle 10g RAC on IBM power server but while running CRS getting the following errors. Please help to resolve this issue.
OUTPUT from Installation log:
INFO: Start output from spawned process:
INFO: INFO:
INFO: /oracle/app/oracle/product/crs/bin/genclntsh
INFO: /usr/bin/ld: cannot find -lxl
INFO: collect2: ld returned 1 exit status
INFO: genclntsh: Failed to link libclntsh.so.10.1
INFO: make:
INFO: *** [client_sharedlib] Error 1
INFO: End output from spawned process.
INFO: INFO: Exception thrown from action: make
Exception Name: MakefileException
Exception String: Error in invoking target 'client_sharedlib' of makefile '/oracle/app/oracle/product/crs/network/lib/ins_net_client.mk'. See '/oracle/app/oracle/oraInventory/logs/installActions2011-12-26_04-40-48PM.log' for details.
Exception Severity: 1
INFO: Exception handling set to prompt user with options to Retry Ignore
SYSTEM:
IBM power server
Linux 5.3
I have already tried changing ORACLE_HOME,CRS_HOME,LD_LIBRARY_PATH but nothing worked.
Regards,
Prajash

Those errors remind me on errors I encountered when I was trying to do installation that was not certified,
so try to check if installation you are doing is actually supported.
In the meantime , visit metalink and read document [ID 460969.1] , */usr/bin/ld: Cannot Find -lxml10, Genclntsh: Failed To Link Libclntsh.so.10.1*

Oracle 10g RAC

Hi All,
I am a research student currently struggling to install Oracle 10g RAC on Windows OS.What i understand about a Oracle RAC database system is that it involves a configuration of multiple hosts or servers joined together with a clustering software and accessing the shared disk structures.What i also understand is that i need a CRS provided by Oracle for a Windows or Linux based RAC installation.
What i don't understand is for a Two node RAC system do i need a Third machine which has the shared storage device.If yes do i have to install a copy of Oracle 10g Enterprise Edition and CRS on the shared storage device moreover do i need to install a copy of Oracle 10g Enterprise edition on each of the nodes or just the clusterware is enough.

Hi Salil
No, you do not need a third machine. You can even setup RAC as a single node on one machine! What you do need is to have some sort of cluster aware file system. Try looking at OCFS on Windows in your case.
If you are interested in a Linux example please have a look at the examples at http://ocpdba.net/oracle9i_rac/cheaprac.html and http://ocpdba.net/oracle10g_rac for an OCFS implementation I am working on.
regards,
Ahbaid

Oracle 9i rac cache fusion queries

Similar Messages

Maybe you are looking for