Administration

How to Resolve ORA-23421: job number is not a job in the job queue

by Ed Chen
January 13, 2018December 11, 2022

ORA-23421 When I tried to remove a given job from the queue, the statement failed with ORA-23421, and ORA-06512 are also in the error stack.… Read More »

How to Resolve ORA-27492: unable to run job: scheduler unavailable

by Ed Chen
January 7, 2018October 30, 2021
8 Comments

ORA-27492 Found error ORA-27492 when executed a tuning job. BEGIN SYS.DBMS_SCHEDULER.RUN_JOB (job_name => 'SYS.SQLTUNE_JOB_61535_2043' ,use_current_session … Read More »

Where is Oracle PFILE Location

by Ed Chen
September 9, 2017December 11, 2022

If we were trying to change parameters in an unfamiliar database that was handed over from other DBA, we have to figure it out whether… Read More »

Relationships among DB_NAME, DB_UNIQUE_NAME, SERVICE_NAMES, INSTANCE_NAME, and $ORACLE_SID

DB_NAME vs DB_UNIQUE_NAME

by Ed Chen
January 14, 2017December 11, 2022

Names Among MAA Under Oracle Maximum Availability Architecture (MAA), we might be confused about various kinds of name. Here I try to clarify these names… Read More »

How to Resolve ORA-00001: unique constraint (PERFSTAT.STATS$SQL_SUMMARY_PK) violated

by Ed Chen
January 7, 2017May 17, 2023

STATSPACK ORA-00001 Login as PERFSTAT and took a snapshot like the following statement. But it failed with ORA-00001. SQL> exec statspack.snap(i_snap_level=>5); BEGIN statspack.snap(i_snap_level=>5); END; *… Read More »

How to Resolve ORA-02085: database link SOURCE_LINK connects to SOURCE_DATABASE

by Ed Chen
December 19, 2016May 18, 2023
4 Comments

ORA-02085 I created a database link without any problem. But when I tried to test the link, I got ORA-02085. SQL> select sysdate from dual@source_link;… Read More »

Gather Database Statistics Examples

by Ed Chen
November 19, 2016May 16, 2023

How to Use DBMS_STATS.GATHER_DATABASE_STATS ? We usually gather statistics of the database globally after data migration. The following examples are very practical in post-migration phase.… Read More »

How to Suspend an Oracle Session

by Ed Chen
July 9, 2016February 14, 2023

Given a session which was consuming lots of resource on Oracle database server, what should we do about the session? Killing the session might be… Read More »

How to Know Everything about an Unfamiliar Database

by Ed Chen
June 14, 2016February 2, 2023

In an unfamiliar environment, if there's only oracle or grid account is available for DBA to use, how can he to know everything about the database… Read More »

Can I Open Database to READ ONLY with RESETLOGS?

by Ed Chen
April 14, 2016December 19, 2021

You can have this one: SQL> ALTER DATABASE OPEN READ ONLY; And also this one: SQL> ALTER DATABASE OPEN RESETLOGS; But there's NO combined statement like… Read More »

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