SQL*Plus error logging truncate does not work - oracle

Question

My scripts use SQL*Plus error logging to track errors during installation.
The scripts start like this - they enable erorr logging and truncate any existing entries:
SQL> set errorlogging on truncate
SQL> select * from table_does_not_exist;
select * from table_does_not_exist
*
ERROR at line 1:
ORA-00942: table or view does not exist
Then at the very end I query sperrorlog to see what went wrong:
SQL> select statement from sperrorlog;
STATEMENT
--------------------------------------------------------------------------------
select * from table_does_not_exist
But every now and then the truncate does not work, and I get errors from previous installations. Why doesn't truncate work?

Answer 1

Despite it's name, SQL*Plus error logging truncate does not actually truncate the table. It deletes the data and does not commit.
This SQL*Plus session enables error logging and creates an error. Another call to enable errorlogging and truncate does clear out the data, but the rollback undoes the truncate.
SQL> set errorlogging on truncate
SQL> select * from table_does_not_exist;
select * from table_does_not_exist
*
ERROR at line 1:
ORA-00942: table or view does not exist
SQL> commit;
Commit complete.
SQL> set errorlogging on truncate
SQL> select statement from sperrorlog;
no rows selected
SQL> rollback;
Rollback complete.
SQL> select statement from sperrorlog;
STATEMENT
--------------------------------------------------------------------------------
select * from table_does_not_exist
SQL>
To be safe, you should always issue a commit right after set errorlogging on truncate.

Answer 2

To be safe, you should always issue a commit right after set errorlogging on truncate
Or, do an explicit TRUNCATE which would do an implicit commit being DDL statement. Of course, this is just like not using the truncate option, however, so is the problem with the rollback. I found the workaround for the rollback issue and shared it in my blog SQL*Plus error logging – workaround for ROLLBACK issue
Coming back to your issue, I am trusting more on an explicit truncate:
SQL> set errorlogging on
SQL> select * from table_does_not_exist;
select * from table_does_not_exist
*
ERROR at line 1:
ORA-00942: table or view does not exist
SQL> select statement from sperrorlog;
STATEMENT
----------------------------------------
select * from table_does_not_exist
SQL> truncate table sperrorlog;
Table truncated.
SQL> select statement from sperrorlog;
no rows selected
SQL> rollback;
Rollback complete.
SQL> select statement from sperrorlog;
no rows selected
SQL>
Alternatively, you could use global temporary table for sperrorlog table and make it on commit delete rows.