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Oracle: error messages for read only database

The old Oracle database (8i) was switched to the read-only mode. The following messages are shown now in alert.log: ***Warning – Executing transaction without active Undo Tablespace

It’s possible, that the error is caused by Oracle bug 3270493 (EXCESSIVE QMNX TRACE FILES WHEN PLACING STANDBY IN READ ONLY MODE). Workaround is to set aq_tm_processes parameter […]

Oracle: read the entries from alert log

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)/ ) { […]

Write to the alert log from PL/SQL code

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

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


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


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 […]