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AskDba.org Weblog » Archive for July 2008

Enabling Flashback On RAC Database

July 28th, 2008 | Add a Comment

Enabling Flashback /Archive Log mode on a Single Instance Database is quite straight forward. In case of RAC, you need to follow additional steps. The requirements for enabling Flashback Database are: Your database must be running in ARCHIVELOG mode, because archived logs are used in the Flashback Database operation. You must have a flash recovery area enabled, because flashback logs can only be stored in the flash recovery area. For Real Application Clusters databases, the flash recovery area must be stored in a clustered file system or in ASM. First of all configure flash recovery area by setting db_recovery_file_dest_size and db_recovery_file_dest ALTER SYSTEM SET DB_RECOVERY_FILE_DEST_SIZE = 20G SCOPE=BOTH; ALTER SYSTEM SET DB_RECOVERY_FILE_DEST = '+DG1' SCOPE=BOTH; We are using ASM Diskgroup here which is sharable and available to both the nodes.Next step is to enable archivelog mode and … Read entire article »

Filed under: oracle, rac

11g New Feature: Database Replay

July 26th, 2008 | 1 Comment

Database Replay: In critical production systems, before making changes to the environment( Hardware or software related), lots of testing is required in test systems to know the effect of those changes and this usually takes lots of time to test for the stability and effects of the change. In Oracle 11g this thing is simplified and a new feature “database replay” is added which can be used to simulate the production workload on a test system. Following are the three stages of DATABASE REPLAY: 1. Workload Capture 2. Workload Preprocessing 3. Workload Replay 1. Workload Capture: Before starting the capture process you need to take care of following things: - Login as sys user - It is always recommened (not mandatory) to shutdown the database and then start the database in restricted mode. By doing so, you will … Read entire article »

Filed under: oracle, performance

10.2.0.4 Window’s Patchset overwrites Sqlnet.ora

July 24th, 2008 | Add a Comment

Not sure, how many of you are aware of this alert. Oracle has published an Alert document NOTE:726418.1 -ALERT: The 10.2.0.4 Windows Patchset Overwrites %ORACLE_HOME%\network\admin\sqlnet.ora According to it, Patch 6810189 – 10.2.0.4 RDBMS patchset on Microsoft Windows (32-bit) and Microsoft Windows (AMD64 and EM64T) overwrites the %ORACLE_HOME%\network\admin\sqlnet.ora file. In case you have Downloaded (and installed) the 10.2.0.4 patchset for Windows before 10 July, 2008 , then please download the software again. In case you have not customized the sqlnet.ora file, then no action is needed. … Read entire article »

Filed under: database, oracle

Simplified Approach to Resolve ORA-4031

July 21st, 2008 | 4 Comments

After writing few Case studies and other related articles, I will be sharing my approach for Resolving ORA -4031 error. First we will see what ORA-4031 actually means. 04031, 00000, "unable to allocate %s bytes of shared memory (\"%s\",\"%s\",\"%s\,\"%s\")" // *Cause: More shared memory is needed than was allocated in the shared pool. // *Action: If the shared pool is out of memory, either use the // dbms_shared_pool package to pin large packages, // reduce your use of shared memory, or increase the amount of // available shared memory by increasing the value of the // INIT.ORA parameters "shared_pool_reserved_size" … Read entire article »

Filed under: Featured, database, oracle

Oracle Database 11G Installation on Solaris 10

July 12th, 2008 | 19 Comments

I had installed Oracle Database 11g on Solaris 10 few days back. I thought of documenting the steps for easy reference. Please find below steps for the same Installation Pre-Requisite Refer to Oracle Database Installation Guide 11g Release 1 (11.1) for Solaris Operating System for checking Hardware and Software Requirements. User Creation and Environment Settings 1)Create groups for Oracle account #groupadd oinstall #groupadd dba #groupadd oper 2)Create Oracle Default Home directory # mkdir /export/home # mkdir /export/home/oracle 3)Create Oracle user # useradd -g oinstall -G dba -d /export/home/oracle -s /usr/bin/bash oracle # chown oracle:oinstall /export/home/oracle 4)Create Project for Oracle for setting the kernel parameters In case of Solaris 10, you can use projects to configure the kernel parameters instead of /etc/system file. This can be done as following # projadd -U oracle -K "project.max-shm-memory=(priv,4g,deny)" oracle # projmod -sK "project.max-sem-nsems=(priv,256,deny)" oracle # projmod -sK "project.max-sem-ids=(priv,100,deny)" oracle # projmod -sK "project.max-shm-ids=(priv,100,deny)" … Read entire article »

Filed under: Install, oracle

Effect of OS Terminal Setting “STTY” on Oracle Database

July 6th, 2008 | Add a Comment

Few days back, while trying to create a synonym over dblink I experienced following error: SQL> create synonym synonymn_name for dual@DBLINK9i; SP2-0042: unknown command "DBLINK9i" - rest of line ignored Strange error !!! Also while trying to perform a simple select statement over another dblink: SQL > select * from dual@dblink10g; SP2-0042: unknown command "DBLINK10g" - rest of line ignored. It also failed with a similar error, though the select over this dblink was working fine earlier.The tnsnames.ora entry was correct and double checked.So what happened to this dblink now? From other database I was able to perform a simple select over same dblink. While I was researching this, I came to know that sql queries also started failing : SQL> UPDATE HRRECORD_TEST SET EMAIL_ADDRESS = 'abc@123.com' WHERE NAME = 'XYZ'; SP2-0734: unknown command beginning "123.com'..." - rest of line ignored. SQL> One … Read entire article »

Filed under: database, oracle

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