Comments on: Little Things Doth Crabby Make Part III. Non-Erroring Errors and Erroneous Experiments.

By: Freek

Freek — Sat, 29 Mar 2008 22:58:18 +0000

Kevin,

Even so, sqlplus would receive an “enter” if the statement was followed by a blank line.
If your “alter session” would have been directly followed by the select statement, sqlplus would have given an error message:

sys@ORCL> host type c:\little_things.sql
alter session set nls_date_format=’DD/MM/YYYY HH24:MI:SS’

select sysdate from dual;

alter session set nls_date_format=’DD/MM/YYYY HH24:MI:SS’;

select sysdate from dual;

alter session set nls_date_format=’DD/MM/YYYY’
select sysdate from dual;

sys@ORCL> @c:\little_things.sql
sys@ORCL> alter session set nls_date_format=’DD/MM/YYYY HH24:MI:SS’
2
sys@ORCL> select sysdate from dual;

SYSDATE
———-
29/03/2008

sys@ORCL>
sys@ORCL>
sys@ORCL> alter session set nls_date_format=’DD/MM/YYYY HH24:MI:SS’;

Session altered.

sys@ORCL>
sys@ORCL> select sysdate from dual;

SYSDATE
——————-
29/03/2008 18:12:43

sys@ORCL>
sys@ORCL> alter session set nls_date_format=’DD/MM/YYYY’
2 select sysdate from dual;
select sysdate from dual
*
ERROR at line 2:
ORA-00922: missing or invalid option

By: Gary

Gary — Sat, 29 Mar 2008 21:29:49 +0000

In a .sql script, you wouldn’t expect an SQL command to be discarded, so there really should be an error that could be caught (or at least reported on so that you could search for it in a log file).

Actually SET SQLBLANKLINES ON would have had that effect, as the new line wouldn’t have terminated the SQL command. Perhaps I should recommend that as a ‘good practice’ for SQL scripts.

By: kevinclosson

kevinclosson — Sat, 29 Mar 2008 17:06:11 +0000

Freek,

This was not an interactive SQL*Plus session…it is in a .sql
script…so, I never hit enter at all

By: Freek

Freek — Sat, 29 Mar 2008 13:10:59 +0000

yep,

you would expect that sqlplus would keep asking for the semicolon. Instead it ignores (silently) the command when you just hit enter again.

By: Hemant K Chitale

Hemant K Chitale — Sat, 29 Mar 2008 07:33:17 +0000

That’s a 9.64% increase in query response time
on what can be a very large table. I wouldn’d
find that worthy of a remark. [oops, I am
making an observation about it ?]

[I remember that the 11i upgrade scripts had a
few bugslogged for queries on this table
during the upgrade process.]

By: Rob Johnson

Rob Johnson — Fri, 28 Mar 2008 21:05:29 +0000

The first “alter session” command didn’t execute because there was no semicolon at the end, but the second alter session command did execute. Does that explain the discrepancy in the timings, although they are fairly close?