Oracle: read the entries from alert log

admin — Mon, 21 Sep 2009 12:08:49 +0000

Sometimes it’s necessary to read the information from the alert log together with the timestamp of the error.

The very simple Unix-shell script helps to do this:

echo
echo 'Enter # of lines:'
read NUM
tail -$NUM alert_${ORACLE_SID}.log | awk '
BEGIN {prev="" ; ret=1 }
/^(...-|Error)/ { if ( prev !~ /^(...-|Error)/ ) { print "" ; print prev;} print $0;ret=0}
{prev=$0}
END { exit ret } '

This code could be assigned to some hotkey in Your favorite telnet application, so You just need to press something like “Alt+A” to see the quick review of the recent Oracle errors.

Example:

Enter # of lines:
1000

Sep 01 19:42:03 2009
Errors in fileARC0: Archiving not possible: error count exceeded

Sep 01 19:42:06 2009
Errors in file testsrv_arc0_23486.trc:
ORA-16038: log 1 sequence# 112 cannot be archived
ORA-19502: write error on file “”, blockno (blocksize=)
ORA-00312: online log 1 thread 1: ‘redo_g1_m1.log’

Write to the alert log from PL/SQL code

admin — Tue, 15 Sep 2009 22:02:56 +0000

The following undocumented function could be used to write to the alert log:

EXECUTE sys.dbms_system.ksdwrt(code, message);

Parameters:

1 – Write to trace file.
2 – Write to alertlog.
3 – Write to both.

Example:

EXECUTE sys.dbms_system.ksdwrt(2,TO_CHAR(SYSDATE, 'Dy Mon DD HH24:MI:SS YYYY')||'Hello!' );

CREATE OR REPLACE TRIGGER trg_delme
BEFORE UPDATE ON frodo.delme
REFERENCING NEW AS NEW OLD AS OLD
FOR EACH ROW
BEGIN
sys.dbms_system.ksdwrt(2,TO_CHAR(SYSDATE, 'Dy Mon DD HH24:MI:SS YYYY') );
END;

MemoSoup » alert log

Oracle: read the entries from alert log

Write to the alert log from PL/SQL code