World of Oracle DBA

In many cases we need to find out the name of the latest trace file generated in the USER_DUMP_DEST directory. What we usually do is go to physically to the USER_DUMP_DEST with the operating system browser and sort all the files by date and look for latest files. We can remove this hassle easily if we know what would be the trace file name in advance. For example issuing, D:\>sqlplus / as sysdba SQL*Plus: Release 10.2.0.1.0 - Production on Wed Jun 10 21:58:15 2009 Copyright (c) 1982, 2005, Oracle. All rights reserved. Connected to: Oracle Database 10g Enterprise Edition Release 10.2.0.1.0 - Production With the Partitioning, OLAP and Data Mining options SQL> alter database backup controlfile to trace; Database altered. SQL> ALTER DATABASE BACKUP CONTROLFILE TO TRACE; will generated a trace file inside USER_DUMP_DEST. Let's see the location of USER_DUMP_DEST. If you use Sql*plus then issue, SQL> show parameter user_dump_dest NAME TYPE

However if you merely see ORA-27100 error upon startup then proceed with this post. Problem Description When you try to startup your database instance even you issue startup nomount ORA-27100 is reported. SQL> startup nomount ORA-27100: shared memory realm already exists Similarly, if you try to shutdown your oracle instance then ORA-27100 is reported. SQL> shutdown immediate ORA-01034: ORACLE not available ORA-27101: shared memory realm does not exist Restarting the service also does not help any. And even in some cases, rebooting the server does not help as well. Current Changes in the Server We had sga_max_size to 600M and then we change it to 1G. After that whenever we restart oracle database above message rises. Cause of the Problem Some changes are made in sga_max_size or sga parameters. After that database is abnormally shut down whenever you issue startup, ORA-27100 is received as a result of changes made to parameters affecting the SGA size. Solution of the Problem In mo

The G stands for Grid Computing. A common missconception seems to be that grid is just the new name for RAC (having improved RAC) This is not the case. 10g comes with both RAC and grid. One will be able to install 10g with RAC only, with grid only, without either and with both. There is a profound difference between grid and RAC. 10g is said to have 149 new features. 10g provides a wealth of features that can be used to automate almost every aspect of its database administration. It is important to note that these automation features are optional, and they are not intended to replace standard DBA activities. Rather, the Oracle10g automation features are aimed at shops that do not have the manpower or expertise to manually perform the tasks. Oracle Enhancements by Oracle Release New Utilities in Oracle10g release 10.1.0: • Oracle10g Grid – RAC enhanced for Oracle10g dynamic scalability with server blades (extra-cost option) • Completely reworked 10g Enterprise Manager (OEM) •

RAC 10g R2 on Red Hat Linux Detail Design and Best Practices Details followed in below link RAC 10g

In many cases you sometimes stop data pump job or in case of an abnormal end of the Data Pump job (the orphaned job) or using undocumented parameter KEEP_MASTER=Y, the master table remain in the database. Though this topic is related to cleanup orphaned datapump jobs. But it is good to know several things before doing cleanup jobs. 1) You can check the orphaned data pump from the state column of the view dba_datapump_jobs and DBA_DATAPUMP_JOBS is based on gv$datapump_job, obj$, com$, and user$. Orphaned Data Pump jobs do not have an impact on new Data Pump jobs. If a new Data Pump job is started, a new entry will be created, which has no relation to the old Data Pump jobs. 2) For a new data pump job without any job name it is used a system generated name. From the dba_datapump_jobs it is checked for existing data pump jobs and then obtain a unique new system generated jobname. 3) Data pump jobs are different from DBMS_JOBS and they are maintained differently. Jobs created with DBMS_JOB

Problem Description E:\>impdp directory=test dumpfile=testexp_07_03_09.dmp userid=shaik/a Import: Release 10.2.0.1.0 - Production on Thursday, 07 May, 2009 10:07:00 Copyright (c) 2003, 2005, Oracle. All rights reserved. Connected to: Oracle Database 10g Enterprise Edition Release 10.2.0.1.0 - Production With the Partitioning, OLAP and Data Mining options ORA-39001: invalid argument value ORA-39000: bad dump file specification ORA-39143: dump file "E:\oracle\Test\testexp_07_03_09.dmp" may be an original export dump file Cause of the problem The above problem happened whenever you try to use the Import Data Pump client (impdp) to import a dumpfile that was created with the original Export client (exp). Though not related but similar error occured. Like whenever you try to import from an empty file, E:\>impdp directory=test dumpfile=testexp_07_03_09.dmp userid=shaik/a Import: Release 10.2.0.1.0 - Production on Thursday, 07 May, 2009 10:16:52 Copyright (c) 2003, 2005, Orac