Comments on: ORA-01466: unable to read data - table definition has changed

By: roger foley

roger foley — Mon, 22 Sep 2008 23:03:07 +0000

i had this set transaction read only within a package.

When its sys, its ok, when its not sys, its a problem.

By: Asif Momen

Asif Momen — Sun, 12 Aug 2007 10:30:02 +0000

Hi Laurent,

Rightly said. I was testing with user SYS. Below is a test as both SYS and non-SYS user.

SQL> conn test/test@mytestdb
Connected.
SQL>
SQL>
SQL> create table t(x number);

Table created.

SQL>
SQL> set transaction read only ;

Transaction set.

SQL>
SQL> select * from t;
select * from t
*
ERROR at line 1:
ORA-01466: unable to read data - table definition has changed

SQL> drop table t;

Table dropped.

SQL> conn sys/password@mytestdb as sysdba
Connected.
SQL> create table t(x number);

Table created.

SQL> set transaction read only ;

Transaction set.

SQL> select * from t;

no rows selected

By: Laurent Schneider

Laurent Schneider — Thu, 26 Jul 2007 17:14:20 +0000

I made a test on my notebook by running the script 1000 times on various versions

10.2.0.3 : reproduced 97.2%
9.2.0.8 : reproduced 96.9%
10.1.0.5 : reproduced 98.7%
11.1.0.5 beta : reproduced 94.8%

all versions affected, none consistently

By: Laurent Schneider

Laurent Schneider — Thu, 26 Jul 2007 16:53:25 +0000

what is your user? If you use SYS, it is not reproducible, because set transaction read only does not work for SYS

By: Laurent Schneider

Laurent Schneider — Wed, 25 Jul 2007 09:29:08 +0000

interesting! thanks for the test case

By: Asif Momen

Asif Momen — Wed, 25 Jul 2007 08:02:52 +0000

Hi Laurent,

My database server is Oracle 10g Release 2 on AIX box, and my client is on Windows. I reset the time of my client to be +2 hours and -2 hours of the server time and ran the test, but I did not face ORA-01466 error. I placed the create table, set transtaction, and the select in a script and ran it.

Following is the ouput of my run (in both cases where my client time is +2 and -2 hours from the database servers time).

SQL> @c

Table created.

Transaction set.

no rows selected

Following are the contents of my script “c.sql”

create table t(x number);

set transaction read only ;

select * from t;

I couldn’t reproduce the ORA-01466 error.

By: Bob Carlton

Bob Carlton — Tue, 17 Jul 2007 06:11:43 +0000

Yes, copy/paste also generates the error. I tried it with host sleep 15, 5 and even 1 second and they were all ok. ( see commented sections below).

– copy/pasted and got an error –
SQL> drop table t
2 /

Table dropped.

SQL>
SQL> create table t( x number )
2 /

Table created.

SQL>
SQL> set transaction read only;

Transaction set.

SQL>
SQL> select * from t;
select * from t
*
ERROR at line 1:
ORA-01466: unable to read data - table definition has changed

SQL>

——copy/pasted w sleep 15 seconds, ok —-
SQL> drop table t
2 /

Table dropped.

SQL>
SQL> create table t( x number )
2 /

Table created.

SQL>
SQL> host sleep 15

SQL>
SQL> set transaction read only;

Transaction set.

SQL>
SQL> select * from t;

no rows selected

——copy/pasted w sleep 5 seconds, ok —-
SQL> drop table t
2 /

Table dropped.

SQL>
SQL> create table t( x number )
2 /

Table created.

SQL>
SQL> host sleep 5

SQL>
SQL> set transaction read only;

Transaction set.

SQL>
SQL> select * from t;

no rows selected

——copy/pasted w sleep 1 seconds! ok —-

SQL> drop table t
2 /

Table dropped.

SQL>
SQL> create table t( x number )
2 /

Table created.

SQL>
SQL> host sleep 1;

SQL>
SQL> set transaction read only;

Transaction set.

SQL>
SQL> select * from t;

no rows selected

SQL>

By: Laurent Schneider

Laurent Schneider — Fri, 13 Jul 2007 18:50:19 +0000

what about copy pasting all command in one step? I think it is due to the time you need to type “set transaction readonly [enter]“

By: Bob Carlton

Bob Carlton — Fri, 13 Jul 2007 17:39:57 +0000

Are you running this from a script? i.e @myfile.sql

I get the same error when run via a sqlplus script.

When I key each command in one by one at the prompt no error.

I believe it’s the SQL cache.

When keying (in my normal slow manner. ha ha.) it doesn’t seem to matter if my client time is different then the server time.

using sqlplus script ———-

SQL> @test

Table dropped.

Table created.

Transaction set.

select * from t
*
ERROR at line 1:
ORA-01466: unable to read data - table definition has changed

hand keyed——

SQL> drop table t;

Table dropped.

SQL> create table t( x number);

Table created.

SQL> set transaction read only;

Transaction set.

SQL> select * from t;

no rows selected

SQL>

By: Laurent Schneider

Laurent Schneider — Wed, 11 Jul 2007 15:40:40 +0000

it is perhaps due to the non-accuracy of translation of the last ddl time to a scn