Administration

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

by Ed Chen
December 19, 2016November 11, 2023
6 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 »

UNDO_RETENTION, How and Why

by Ed Chen
April 7, 2016November 12, 2023

UNDO_RETENTION At times, you may find out or feel that UNDO_RETENTION is useless at all. Raising the number of seconds cannot resolve ORA-01555. This is… Read More »

Why Enable Unified Audit Trail in 12c

by Ed Chen
October 10, 2015March 30, 2018

In my opinion, the reason in short is that the unified audit systematically unify all required audit operations into a single, consolidated fashion.According Oracle 12c… Read More »

The Scope of "AUDIT POLICY XXX"

by Ed Chen
September 25, 2015May 17, 2019

When you issue the very simple unified audit without any modifiers like this:SQL> AUDIT POLICY ORA_DATABASE_PARAMETER; The scope of the audit seems to be very… Read More »

Possible Reasons Why Shutdown Stuck

by Ed Chen
September 12, 2014February 14, 2023

The fastest way to solve the hanging is to do a SHUTDOWN ABORT or even kill SMON process, but they do not remove the root… Read More »

How to Resolve "PMON failed to acquire latch, see PMON dump"

by Ed Chen
September 5, 2014April 20, 2018
2 Comments

PMON failed to acquire latch Here was the case, the database was hanging caused by some heavy loading processes. Users complained about the high waiting… Read More »

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