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Where is Oracle Alert Log Location

Finding Oracle Alert Log Location

The Default Oracle Alert Log Location

Oracle alert log location may vary from version to version, and sometimes it's not easily found. However, it usually locates at 3 locations.

For 11g and later releases (12c, 18c, 19c)


As we can notice, Oracle software divides alert logs to their own dedicated directories according to their database unique names, which is based on directory structure of diagnostic repository.

For 9i and 10g


It's in bdump.

For rest of cases without any clues


Which is the same way to determine DIAGNOSTIC_DEST.

Filename Format of Alert Log

Even though its location may vary from version to version, the alert log file name is always:


Occasionally, you cannot find the alert log file anywhere. Next, let's see how we can find it.

3 Ways to Find Oracle Alert Log Location

Here I introduce three ways to find the right Oracle alert log location.

1. Background Dump Destination

If you are a DBA, you can query the value of BACKGROUND_DUMP_DEST, an initialization parameter, where you can find Oracle alert log.

SQL> show parameter background_dump_dest;

NAME                                 TYPE        VALUE
------------------------------------ ----------- ------------------------------
background_dump_dest                 string      /u01/app/oracle/diag/rdbms/orc

Or in this way:

SQL> select value from v$parameter where name = 'background_dump_dest';


In case that you cannot query the database, you can still find the location of alert log at OS-level.

2. Using Find Command

Almost all UNIX and Linux have find command, so using it to find some files is a very common way to do it.

[oracle@test ~]$ find $ORACLE_BASE -type f -name alert_$ORACLE_SID.log

We find a file named alert_$ORACLE_SID.log starting from $ORACLE_BASE. As we can see, the file was found.

3. Using Locate Command

Sometimes, using locate command will be faster than find to find the path of alert log file.

[oracle@test ~]$ locate alert_$ORACLE_SID.log

In some databases, the alert logs are big, maybe too big to make room for other files. We have to know ways to reduce the size of alert logs.

For your reference, the ways to find the location of listener log are slightly different from the ways we find Oracle alert log. You can take a look.

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