Re: DDLs -- was Re: simple question on DDL
My point wasn't to pick any particular detail
of any particular example . I was merely making
the point that whilst the concept of DDL without
commits seems to be straightforward, the requirement
for designing something that could analyse and handle
all the consequent errors that might be a non-trivial
problem.
Regards
Jonathan Lewis
http://www.jlcomp.demon.co.uk
Coming soon a new one-day tutorial:
Cost Based Optimisation
(see http://www.jlcomp.demon.co.uk/tutorial.html )
UK___March
USA_(FL)_May
Next Seminar dates:
(see http://www.jlcomp.demon.co.uk/seminar.html )
USA_(CA, TX)_August
The Co-operative Oracle Users' FAQ
http://www.jlcomp.demon.co.uk/faq/ind_faq.html
-Original Message-
To: Multiple recipients of list ORACLE-L <[EMAIL PROTECTED]>
Date: 24 January 2003 16:40
>
>Take your first example :
>insert into t1 values (1);
>drop table t1;
> -- how to deal with self-deadlock ?
>insert into t1 values (2);
>commit;
>
>Why does Oracle HAVE to commit when the DROP TABLE is issued ?
>What if the INSERT had been issued by another session ? Would
>the DROP TABLE go through in this session ?
>The "self-deadlock" could be handled as an Error -- a Transaction
error,
>with a message like "cannot drop table when transaction is active in
>current session".
>A duhveloper who has written a very long-winded .SQL file or
procedure
>and tries to drop a Table when he has an active transaction should be
>caught and "errored" -- he shouldn't be allowed to drop his own
table, he
>has made a logical error.
>
>Take the second example :
>insert into t1 values (1);
>drop table t2;
> -- how to deal with lock by other user ?
>insert into t1 values (2);
>commit;
>
>If the DROP TABLE may have to wait for another user who has a lock
on T2,
>why should the INSERT INTO T1 be committed ? Our user hasn't
completed
>his transaction yet.
>
>It all depends on what you mean by a "Transaction". The way Oracle
has
>written DDLs, a "Transaction" ends and is committed when the next DDL
>is issued. But that may not be a logical transaction in the real
world.
>
>My point is not that the DROP TABLE should be "roll-backable". The
DROP
>TABLE itself must always commit it's own statement. --- it's own
statement.
>That is to ensure that a third user does not see inconsistency when
running
>a transaction accessing T1. But why should the DROP TABLE explicitly
>commit the previous statement ? In your example, you have shown that
>an inconsistency may arise when a DROP is issued on a table with an
>outstanding transaction.
>
>But take the case where :
>INSERT INTO T10 values ('a');
>-- now I want to, for the heck of it, or bec'ose I'm a bad programmer
...
>DROP TABLE XYZ ;
>-- oops, my INSERT INTO T10 should be rolled back
>-- but the Drop XYZ is independent
>ROLLBACK;
>
>Here, unfortunately, the DROP TABLE XYZ had already committed the
INSERT
>INTO T10.
>I didn't want that !
>It would have been better if this DROP TABLE XYZ was an Autonomous
Transaction.
>But in the first example, the DROP TABLE T1 should return an error.
>So, the Oracle Kernel must have some more complexity to see if
there's any
>outstanding
>transaction in the current session [it already checks for other
sessions
>because they
>hold TM locks on the Table !] are pending against the same table
being dropped.
>
>Hemant
>
--
Please see the official ORACLE-L FAQ: http://www.orafaq.net
--
Author: Jonathan Lewis
INET: [EMAIL PROTECTED]
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RE: DDLs -- was Re: simple question on DDL
Agreed. There's a lot of code out there that was developed considering the
way Oracle handled DDL and DML specifically.
Although I would have liked Oracle to handle DDL as an Autonomous Transaction
and provide an error message for the scenario in the first example, I guess
it might be too late to change the kernel now.
As Arup said, hopefully Oracle 38i will allow us to mix DDL with DML
and yet have DDL as Autonomous Transactions.
When Oracle didn't have Sequences before Oracle6, people wrote code
to SELECT MAX(KEY)+1. There might still be a few developers and
few pieces of code doing precisely that instead of using a sequence [of
course, development which is RDBMS-independent might not use an
Oracle Sequence].
I was just expressing a wish that Oracle could have done DDL and DML
better.We are stuck with QWERTY and we are stuck with DDL
that does an Auto-Commit.
Hemant
At 10:49 AM 24-01-03 -0800, you wrote:
Tom - I think you've nailed it. Think of the design decisions that some of
Oracle's competitors made in the early days and how silly they seem in
retrospect. Anyone remember the row-locking vs. block-locking wars?
The other aspect that many people don't think of if they have never
worked in a vendor's development staff is inertia. You as a developer are
assigned a list of tasks which is usually larger than you can accomplish.
Marketing bases those tasks on 1) which features will get more customers or
2) what customers are howling about -- where is the ROI? Changing how the
kernel works is a high-risk business, so I think you are probably stuck with
the way it works, even if you feel it is inconsistent.
If Oracle did go back and "fix" stuff in this area, there may be customer
scripts that rely on this behavior, even if we feel it is inconsistent.
-Original Message-
Sent: Friday, January 24, 2003 11:35 AM
To: Multiple recipients of list ORACLE-L
Hemant,
My guess is that Oracle, at some point in time long ago, decided that DDL's
and DML's should not be mixed together. Because they could not (or did not
want to) deal with the issue, they decided to perform an implicit commit
before any DDL statement was issued. Case closed. This is the way it was
done.
Things have changed in the (more than??) 10 years that this code was
written. We are all smarter and have much more experience in what we would
like to see happen, rather than how it is currently coded. Could Oracle
change this code? Absolutely. Will they? Only if enough people ask for it
to be changed. Would I like to see it changed? No. I really don't see the
need. I think DDL and DML are two different things and should not be mixed
together. If they are mixed together, then developers need to learn how it
works and deal with it.
just my 2 cents.
Tom Mercadante
Oracle Certified Professional
-Original Message-
Sent: Friday, January 24, 2003 10:30 AM
To: Multiple recipients of list ORACLE-L
Take your first example :
insert into t1 values (1);
drop table t1;
-- how to deal with self-deadlock ?
insert into t1 values (2);
commit;
Why does Oracle HAVE to commit when the DROP TABLE is issued ?
What if the INSERT had been issued by another session ? Would
the DROP TABLE go through in this session ?
The "self-deadlock" could be handled as an Error -- a Transaction error,
with a message like "cannot drop table when transaction is active in
current session".
A duhveloper who has written a very long-winded .SQL file or procedure
and tries to drop a Table when he has an active transaction should be
caught and "errored" -- he shouldn't be allowed to drop his own table, he
has made a logical error.
Take the second example :
insert into t1 values (1);
drop table t2;
-- how to deal with lock by other user ?
insert into t1 values (2);
commit;
If the DROP TABLE may have to wait for another user who has a lock on T2,
why should the INSERT INTO T1 be committed ? Our user hasn't completed
his transaction yet.
It all depends on what you mean by a "Transaction". The way Oracle has
written DDLs, a "Transaction" ends and is committed when the next DDL
is issued. But that may not be a logical transaction in the real world.
My point is not that the DROP TABLE should be "roll-backable". The DROP
TABLE itself must always commit it's own statement. --- it's own statement.
That is to ensure that a third user does not see inconsistency when running
a transaction accessing T1. But why should the DROP TABLE explicitly
commit the previous statement ? In your example, you have shown that
an inconsistency may arise when a DROP is issued on a table with an
outstanding transaction.
But take the case where :
INSERT INTO T10 values ('a');
-- now I want to, for the heck of it, or bec'ose I'm a bad programmer ...
DROP TABLE XYZ ;
-- oops, my INSERT INTO T10 should be rolled back
-- but the Drop XYZ is independent
ROLLBACK;
Here, unfortunately, the DROP TABLE XYZ had already committed the INSERT
INTO T10.
I didn't w
RE: DDLs -- was Re: simple question on DDL
> I think DDL and DML are two different things and should not be mixed > together. If they are mixed together, then developers need to learn how it > works and deal with it. And there you have it. If you need DDL in your code, isolate it in an anonymous transaction, or just be sure that you are at a safe commit point. jared "Mercadante, Thomas F" <[EMAIL PROTECTED]> Sent by: [EMAIL PROTECTED] 01/24/2003 09:34 AM Please respond to ORACLE-L To: Multiple recipients of list ORACLE-L <[EMAIL PROTECTED]> cc: Subject: RE: DDLs -- was Re: simple question on DDL Hemant, My guess is that Oracle, at some point in time long ago, decided that DDL's and DML's should not be mixed together. Because they could not (or did not want to) deal with the issue, they decided to perform an implicit commit before any DDL statement was issued. Case closed. This is the way it was done. Things have changed in the (more than??) 10 years that this code was written. We are all smarter and have much more experience in what we would like to see happen, rather than how it is currently coded. Could Oracle change this code? Absolutely. Will they? Only if enough people ask for it to be changed. Would I like to see it changed? No. I really don't see the need. I think DDL and DML are two different things and should not be mixed together. If they are mixed together, then developers need to learn how it works and deal with it. just my 2 cents. Tom Mercadante Oracle Certified Professional -Original Message- > -- Please see the official ORACLE-L FAQ: http://www.orafaq.net -- Author: INET: [EMAIL PROTECTED] Fat City Network Services-- 858-538-5051 http://www.fatcity.com San Diego, California-- Mailing list and web hosting services - To REMOVE yourself from this mailing list, send an E-Mail message to: [EMAIL PROTECTED] (note EXACT spelling of 'ListGuru') and in the message BODY, include a line containing: UNSUB ORACLE-L (or the name of mailing list you want to be removed from). You may also send the HELP command for other information (like subscribing).
RE: DDLs -- was Re: simple question on DDL
Tom - I think you've nailed it. Think of the design decisions that some of
Oracle's competitors made in the early days and how silly they seem in
retrospect. Anyone remember the row-locking vs. block-locking wars?
The other aspect that many people don't think of if they have never
worked in a vendor's development staff is inertia. You as a developer are
assigned a list of tasks which is usually larger than you can accomplish.
Marketing bases those tasks on 1) which features will get more customers or
2) what customers are howling about -- where is the ROI? Changing how the
kernel works is a high-risk business, so I think you are probably stuck with
the way it works, even if you feel it is inconsistent.
If Oracle did go back and "fix" stuff in this area, there may be customer
scripts that rely on this behavior, even if we feel it is inconsistent.
-Original Message-
Sent: Friday, January 24, 2003 11:35 AM
To: Multiple recipients of list ORACLE-L
Hemant,
My guess is that Oracle, at some point in time long ago, decided that DDL's
and DML's should not be mixed together. Because they could not (or did not
want to) deal with the issue, they decided to perform an implicit commit
before any DDL statement was issued. Case closed. This is the way it was
done.
Things have changed in the (more than??) 10 years that this code was
written. We are all smarter and have much more experience in what we would
like to see happen, rather than how it is currently coded. Could Oracle
change this code? Absolutely. Will they? Only if enough people ask for it
to be changed. Would I like to see it changed? No. I really don't see the
need. I think DDL and DML are two different things and should not be mixed
together. If they are mixed together, then developers need to learn how it
works and deal with it.
just my 2 cents.
Tom Mercadante
Oracle Certified Professional
-Original Message-
Sent: Friday, January 24, 2003 10:30 AM
To: Multiple recipients of list ORACLE-L
Take your first example :
insert into t1 values (1);
drop table t1;
-- how to deal with self-deadlock ?
insert into t1 values (2);
commit;
Why does Oracle HAVE to commit when the DROP TABLE is issued ?
What if the INSERT had been issued by another session ? Would
the DROP TABLE go through in this session ?
The "self-deadlock" could be handled as an Error -- a Transaction error,
with a message like "cannot drop table when transaction is active in
current session".
A duhveloper who has written a very long-winded .SQL file or procedure
and tries to drop a Table when he has an active transaction should be
caught and "errored" -- he shouldn't be allowed to drop his own table, he
has made a logical error.
Take the second example :
insert into t1 values (1);
drop table t2;
-- how to deal with lock by other user ?
insert into t1 values (2);
commit;
If the DROP TABLE may have to wait for another user who has a lock on T2,
why should the INSERT INTO T1 be committed ? Our user hasn't completed
his transaction yet.
It all depends on what you mean by a "Transaction". The way Oracle has
written DDLs, a "Transaction" ends and is committed when the next DDL
is issued. But that may not be a logical transaction in the real world.
My point is not that the DROP TABLE should be "roll-backable". The DROP
TABLE itself must always commit it's own statement. --- it's own statement.
That is to ensure that a third user does not see inconsistency when running
a transaction accessing T1. But why should the DROP TABLE explicitly
commit the previous statement ? In your example, you have shown that
an inconsistency may arise when a DROP is issued on a table with an
outstanding transaction.
But take the case where :
INSERT INTO T10 values ('a');
-- now I want to, for the heck of it, or bec'ose I'm a bad programmer ...
DROP TABLE XYZ ;
-- oops, my INSERT INTO T10 should be rolled back
-- but the Drop XYZ is independent
ROLLBACK;
Here, unfortunately, the DROP TABLE XYZ had already committed the INSERT
INTO T10.
I didn't want that !
It would have been better if this DROP TABLE XYZ was an Autonomous
Transaction.
But in the first example, the DROP TABLE T1 should return an error.
So, the Oracle Kernel must have some more complexity to see if there's any
outstanding
transaction in the current session [it already checks for other sessions
because they
hold TM locks on the Table !] are pending against the same table being
dropped.
Hemant
At 09:50 AM 23-01-03 -0800, you wrote:
>One question to ask is whether whether all DDL
>use the same strategy. Similarly, if you have
>multiple code paths for "do a ddl call" how much
>more risk of error do you introduce to the kernel.
>Finally how do you get a consistent error response
>to the end user if the error condition of apparently
>identical events can fail in extremely different ways.
>
>Consider the complexities of finding a consistent
>kernel level approach to:
>
>insert into t1 values
RE: DDLs -- was Re: simple question on DDL
Hemant,
My guess is that Oracle, at some point in time long ago, decided that DDL's
and DML's should not be mixed together. Because they could not (or did not
want to) deal with the issue, they decided to perform an implicit commit
before any DDL statement was issued. Case closed. This is the way it was
done.
Things have changed in the (more than??) 10 years that this code was
written. We are all smarter and have much more experience in what we would
like to see happen, rather than how it is currently coded. Could Oracle
change this code? Absolutely. Will they? Only if enough people ask for it
to be changed. Would I like to see it changed? No. I really don't see the
need. I think DDL and DML are two different things and should not be mixed
together. If they are mixed together, then developers need to learn how it
works and deal with it.
just my 2 cents.
Tom Mercadante
Oracle Certified Professional
-Original Message-
Sent: Friday, January 24, 2003 10:30 AM
To: Multiple recipients of list ORACLE-L
Take your first example :
insert into t1 values (1);
drop table t1;
-- how to deal with self-deadlock ?
insert into t1 values (2);
commit;
Why does Oracle HAVE to commit when the DROP TABLE is issued ?
What if the INSERT had been issued by another session ? Would
the DROP TABLE go through in this session ?
The "self-deadlock" could be handled as an Error -- a Transaction error,
with a message like "cannot drop table when transaction is active in
current session".
A duhveloper who has written a very long-winded .SQL file or procedure
and tries to drop a Table when he has an active transaction should be
caught and "errored" -- he shouldn't be allowed to drop his own table, he
has made a logical error.
Take the second example :
insert into t1 values (1);
drop table t2;
-- how to deal with lock by other user ?
insert into t1 values (2);
commit;
If the DROP TABLE may have to wait for another user who has a lock on T2,
why should the INSERT INTO T1 be committed ? Our user hasn't completed
his transaction yet.
It all depends on what you mean by a "Transaction". The way Oracle has
written DDLs, a "Transaction" ends and is committed when the next DDL
is issued. But that may not be a logical transaction in the real world.
My point is not that the DROP TABLE should be "roll-backable". The DROP
TABLE itself must always commit it's own statement. --- it's own statement.
That is to ensure that a third user does not see inconsistency when running
a transaction accessing T1. But why should the DROP TABLE explicitly
commit the previous statement ? In your example, you have shown that
an inconsistency may arise when a DROP is issued on a table with an
outstanding transaction.
But take the case where :
INSERT INTO T10 values ('a');
-- now I want to, for the heck of it, or bec'ose I'm a bad programmer ...
DROP TABLE XYZ ;
-- oops, my INSERT INTO T10 should be rolled back
-- but the Drop XYZ is independent
ROLLBACK;
Here, unfortunately, the DROP TABLE XYZ had already committed the INSERT
INTO T10.
I didn't want that !
It would have been better if this DROP TABLE XYZ was an Autonomous
Transaction.
But in the first example, the DROP TABLE T1 should return an error.
So, the Oracle Kernel must have some more complexity to see if there's any
outstanding
transaction in the current session [it already checks for other sessions
because they
hold TM locks on the Table !] are pending against the same table being
dropped.
Hemant
At 09:50 AM 23-01-03 -0800, you wrote:
>One question to ask is whether whether all DDL
>use the same strategy. Similarly, if you have
>multiple code paths for "do a ddl call" how much
>more risk of error do you introduce to the kernel.
>Finally how do you get a consistent error response
>to the end user if the error condition of apparently
>identical events can fail in extremely different ways.
>
>Consider the complexities of finding a consistent
>kernel level approach to:
>
>insert into t1 values (1);
>drop table t1;
> -- how to deal with self-deadlock ?
>insert into t1 values (2);
>commit;
>
>insert into t1 values (1);
>drop table t2;
> -- how to deal with lock by other user ?
>insert into t1 values (2);
>commit;
>
>
>
>Regards
>
>Jonathan Lewis
>http://www.jlcomp.demon.co.uk
>
>Coming soon a new one-day tutorial:
>Cost Based Optimisation
>(see http://www.jlcomp.demon.co.uk/tutorial.html )
>
>Next Seminar dates:
>(see http://www.jlcomp.demon.co.uk/seminar.html )
>
>England__January 21/23
>USA_(CA, TX)_August
>
>
>The Co-operative Oracle Users' FAQ
>http://www.jlcomp.demon.co.uk/faq/ind_faq.html
>
>
>
>
>
>-Original Message-
>To: Multiple recipients of list ORACLE-L <[EMAIL PROTECTED]>
>Date: 23 January 2003 16:31
>
>
> >Arup,
> > I see your point and agree that the DDL should be an autonomous tx.
> >Perhaps an enhancement request is in order? Since Oracle has the
>autonomous
> >tx code, integrating into the kernel should be consi
DDLs -- was Re: simple question on DDL
Take your first example :
insert into t1 values (1);
drop table t1;
-- how to deal with self-deadlock ?
insert into t1 values (2);
commit;
Why does Oracle HAVE to commit when the DROP TABLE is issued ?
What if the INSERT had been issued by another session ? Would
the DROP TABLE go through in this session ?
The "self-deadlock" could be handled as an Error -- a Transaction error,
with a message like "cannot drop table when transaction is active in
current session".
A duhveloper who has written a very long-winded .SQL file or procedure
and tries to drop a Table when he has an active transaction should be
caught and "errored" -- he shouldn't be allowed to drop his own table, he
has made a logical error.
Take the second example :
insert into t1 values (1);
drop table t2;
-- how to deal with lock by other user ?
insert into t1 values (2);
commit;
If the DROP TABLE may have to wait for another user who has a lock on T2,
why should the INSERT INTO T1 be committed ? Our user hasn't completed
his transaction yet.
It all depends on what you mean by a "Transaction". The way Oracle has
written DDLs, a "Transaction" ends and is committed when the next DDL
is issued. But that may not be a logical transaction in the real world.
My point is not that the DROP TABLE should be "roll-backable". The DROP
TABLE itself must always commit it's own statement. --- it's own statement.
That is to ensure that a third user does not see inconsistency when running
a transaction accessing T1. But why should the DROP TABLE explicitly
commit the previous statement ? In your example, you have shown that
an inconsistency may arise when a DROP is issued on a table with an
outstanding transaction.
But take the case where :
INSERT INTO T10 values ('a');
-- now I want to, for the heck of it, or bec'ose I'm a bad programmer ...
DROP TABLE XYZ ;
-- oops, my INSERT INTO T10 should be rolled back
-- but the Drop XYZ is independent
ROLLBACK;
Here, unfortunately, the DROP TABLE XYZ had already committed the INSERT
INTO T10.
I didn't want that !
It would have been better if this DROP TABLE XYZ was an Autonomous Transaction.
But in the first example, the DROP TABLE T1 should return an error.
So, the Oracle Kernel must have some more complexity to see if there's any
outstanding
transaction in the current session [it already checks for other sessions
because they
hold TM locks on the Table !] are pending against the same table being dropped.
Hemant
At 09:50 AM 23-01-03 -0800, you wrote:
One question to ask is whether whether all DDL
use the same strategy. Similarly, if you have
multiple code paths for "do a ddl call" how much
more risk of error do you introduce to the kernel.
Finally how do you get a consistent error response
to the end user if the error condition of apparently
identical events can fail in extremely different ways.
Consider the complexities of finding a consistent
kernel level approach to:
insert into t1 values (1);
drop table t1;
-- how to deal with self-deadlock ?
insert into t1 values (2);
commit;
insert into t1 values (1);
drop table t2;
-- how to deal with lock by other user ?
insert into t1 values (2);
commit;
Regards
Jonathan Lewis
http://www.jlcomp.demon.co.uk
Coming soon a new one-day tutorial:
Cost Based Optimisation
(see http://www.jlcomp.demon.co.uk/tutorial.html )
Next Seminar dates:
(see http://www.jlcomp.demon.co.uk/seminar.html )
England__January 21/23
USA_(CA, TX)_August
The Co-operative Oracle Users' FAQ
http://www.jlcomp.demon.co.uk/faq/ind_faq.html
-Original Message-
To: Multiple recipients of list ORACLE-L <[EMAIL PROTECTED]>
Date: 23 January 2003 16:31
>Arup,
> I see your point and agree that the DDL should be an autonomous tx.
>Perhaps an enhancement request is in order? Since Oracle has the
autonomous
>tx code, integrating into the kernel should be considered...perhaps
for
>Oracle 38i?
> In the absence of that change, I must disagree and say that ddl must
>issue a commit. If you look at a combination of your example and
mine, the
>problem of waiting transactions still exists. In order to create a
table,
>space must be allocated. Again, if fet$ contains only 1 row for the
>particular file where the table is to be created, there is a
potential for a
>serious locking problem.
>
>Dan
--
Please see the official ORACLE-L FAQ: http://www.orafaq.net
--
Author: Jonathan Lewis
INET: [EMAIL PROTECTED]
Fat City Network Services-- 858-538-5051 http://www.fatcity.com
San Diego, California-- Mailing list and web hosting services
-
To REMOVE yourself from this mailing list, send an E-Mail message
to: [EMAIL PROTECTED] (note EXACT spelling of 'ListGuru') and in
the message BODY, include a line containing: UNSUB ORACLE-L
(or the name of mailing list you want to be removed from). You may
also send the HELP command for other information (like subscribing).
Hemant K Chitale
Re: simple question on DDL
One question to ask is whether whether all DDL use the same strategy. Similarly, if you have multiple code paths for "do a ddl call" how much more risk of error do you introduce to the kernel. Finally how do you get a consistent error response to the end user if the error condition of apparently identical events can fail in extremely different ways. Consider the complexities of finding a consistent kernel level approach to: insert into t1 values (1); drop table t1; -- how to deal with self-deadlock ? insert into t1 values (2); commit; insert into t1 values (1); drop table t2; -- how to deal with lock by other user ? insert into t1 values (2); commit; Regards Jonathan Lewis http://www.jlcomp.demon.co.uk Coming soon a new one-day tutorial: Cost Based Optimisation (see http://www.jlcomp.demon.co.uk/tutorial.html ) Next Seminar dates: (see http://www.jlcomp.demon.co.uk/seminar.html ) England__January 21/23 USA_(CA, TX)_August The Co-operative Oracle Users' FAQ http://www.jlcomp.demon.co.uk/faq/ind_faq.html -Original Message- To: Multiple recipients of list ORACLE-L <[EMAIL PROTECTED]> Date: 23 January 2003 16:31 >Arup, > I see your point and agree that the DDL should be an autonomous tx. >Perhaps an enhancement request is in order? Since Oracle has the autonomous >tx code, integrating into the kernel should be considered...perhaps for >Oracle 38i? > In the absence of that change, I must disagree and say that ddl must >issue a commit. If you look at a combination of your example and mine, the >problem of waiting transactions still exists. In order to create a table, >space must be allocated. Again, if fet$ contains only 1 row for the >particular file where the table is to be created, there is a potential for a >serious locking problem. > >Dan -- Please see the official ORACLE-L FAQ: http://www.orafaq.net -- Author: Jonathan Lewis INET: [EMAIL PROTECTED] Fat City Network Services-- 858-538-5051 http://www.fatcity.com San Diego, California-- Mailing list and web hosting services - To REMOVE yourself from this mailing list, send an E-Mail message to: [EMAIL PROTECTED] (note EXACT spelling of 'ListGuru') and in the message BODY, include a line containing: UNSUB ORACLE-L (or the name of mailing list you want to be removed from). You may also send the HELP command for other information (like subscribing).
RE: simple question on DDL
Title: RE: simple question on DDL Set autotrace on ... and then do explain plan for You'll see. Raj __ Rajendra Jamadagni MIS, ESPN Inc. Rajendra dot Jamadagni at ESPN dot com Any opinion expressed here is personal and doesn't reflect that of ESPN Inc. QOTD: Any clod can have facts, but having an opinion is an art! -Original Message-From: Jeremy Pulcifer [mailto:[EMAIL PROTECTED]]Sent: Thursday, January 23, 2003 12:09 PMTo: Multiple recipients of list ORACLE-LSubject: RE: simple question on DDL > From: Gogala, Mladen [mailto:[EMAIL PROTECTED]] > Sent: Thursday, January 23, 2003 8:45 AM > To: Multiple recipients of list ORACLE-L > Subject: RE: simple question on DDL > > > Actually, DB2 (pardon my French) doesn't issue a commit > after a DDL. I'm not aware of any standards specifying > the presence or absence of a "commit" after a DDL. I know > that, for instance, "EXPLAIN PLAN" can be rolled back. > Huh? Explain plan is DDL? This e-mail message is confidential, intended only for the named recipient(s) above and may contain information that is privileged, attorney work product or exempt from disclosure under applicable law. If you have received this message in error, or are not the named recipient(s), please immediately notify corporate MIS at (860) 766-2000 and delete this e-mail message from your computer, Thank you.*2
RE: simple question on DDL
Actually, DB2 (pardon my French) doesn't issue a commit after a DDL. I'm not aware of any standards specifying the presence or absence of a "commit" after a DDL. I know that, for instance, "EXPLAIN PLAN" can be rolled back. > -Original Message- > From: Fink, Dan [mailto:[EMAIL PROTECTED]] > Sent: Thursday, January 23, 2003 10:05 AM > To: Multiple recipients of list ORACLE-L > Subject: RE: simple question on DDL > > > Arup, > I see your point and agree that the DDL should be an > autonomous tx. > Perhaps an enhancement request is in order? Since Oracle has > the autonomous > tx code, integrating into the kernel should be > considered...perhaps for > Oracle 38i? > In the absence of that change, I must disagree and say > that ddl must > issue a commit. If you look at a combination of your example > and mine, the > problem of waiting transactions still exists. In order to > create a table, > space must be allocated. Again, if fet$ contains only 1 row for the > particular file where the table is to be created, there is a > potential for a > serious locking problem. > > Dan > > -Original Message- > Sent: Wednesday, January 22, 2003 7:14 PM > To: Multiple recipients of list ORACLE-L > > > Dan, > > If I may, essentially you are saying that changes to data > dictionary tables > have to be committed immediately regardless of the outcome of the > transaction. > > For instance in the following code, starting with an empty table t1 > > step 1: insert into table t1 values row1 > step 2: create table t2 > step 3: insert into table t1 values row2 > step 4: rollback > > At this point a select * from t1 will show only row1, since > the ddl create > table t2 has inserted a commit. However, the point is, my > transaction should > > have been from step 1 through step 4, not fromn step 3 > through 4. The DDL > broke my txn at step 2 and another transaction started from > there. The data > dictionary tables were updated and they should be committed; > but that commit > > could have been done via an "autonomous transaction", not in the same > transaction the user issued. > > The more I think about it, I see no point why a DDL should > insert a commit. > This is different from saying that DDL itself may issue a > commit to its > seprate transaction to update the catalog. Any thoughts on that? > > Arup > > >From: "Fink, Dan" <[EMAIL PROTECTED]> > >Reply-To: [EMAIL PROTECTED] > >To: Multiple recipients of list ORACLE-L <[EMAIL PROTECTED]> > >Subject: RE: simple question on DDL > >Date: Wed, 22 Jan 2003 14:18:57 -0800 > >MIME-Version: 1.0 > >Received: from newsfeed.cts.com ([209.68.248.164]) by > >mc1-f3.law16.hotmail.com with Microsoft > SMTPSVC(5.0.2195.5600); Wed, 22 Jan > > >2003 15:13:04 -0800 > >Received: from fatcity.UUCP (uucp@localhost)by newsfeed.cts.com > >(8.9.3/8.9.3) with UUCP id PAA16552;Wed, 22 Jan 2003 > 15:11:42 -0800 (PST) > >Received: by fatcity.com (26-Feb-2001/v1.0g-b72/bab) via > UUCP id 00537F3B; > >Wed, 22 Jan 2003 14:18:57 -0800 > >Message-ID: <[EMAIL PROTECTED]> > >X-Comment: Oracle RDBMS Community Forum > >X-Sender: "Fink, Dan" <[EMAIL PROTECTED]> > >Sender: [EMAIL PROTECTED] > >Errors-To: [EMAIL PROTECTED] > >Organization: Fat City Network Services, San Diego, California > >X-ListServer: v1.0g, build 72; ListGuru (c) 1996-2001 Bruce > A. Bergman > >Precedence: bulk > >Return-Path: [EMAIL PROTECTED] > >X-OriginalArrivalTime: 22 Jan 2003 23:13:04.0174 (UTC) > >FILETIME=[D0E4CCE0:01C2C26B] > > > >Don't forget that extent allocation also affects the extent > map for the > >segment and possibly the high water mark. The hwm can be set without > >allocating another extent and allocation of an extent may > not alter the hwm > >(if you manually allocate an extent). If I deallocate space > from an object, > >I will alter the rows in fet$ and uet$ but not update the > hwm. Make sense? > > > >As for the ATOMICITY of the transaction, this is usually > used to describe > >the changes to data of interest. I don't think it is used to > describe any > >underlying data dictionary changes. Thus the answer is Yes > (for 99% of the > >Oracle techies) and No (for the 1% of us who really like to > know exactly > >what is going on under the covers). > > > >Thanks for a great question, it brought up a subject that I had never > >thought about. Yee-Haw! I learned someting tod
RE: simple question on DDL
Title: RE: simple question on DDL > From: Gogala, Mladen [mailto:[EMAIL PROTECTED]] > Sent: Thursday, January 23, 2003 8:45 AM > To: Multiple recipients of list ORACLE-L > Subject: RE: simple question on DDL > > > Actually, DB2 (pardon my French) doesn't issue a commit > after a DDL. I'm not aware of any standards specifying > the presence or absence of a "commit" after a DDL. I know > that, for instance, "EXPLAIN PLAN" can be rolled back. > Huh? Explain plan is DDL?
RE: simple question on DDL
I tend to agree with the argument "that's the way they wrote it".
If I remember correctly, DDL always commits the current transaction
in the session, even back in Oracle5 [and earlier ?] days. Most likely
they couldn't write autonomous transactions then.
That "autonomous transactions" have been available to us since 8i
doesn't mean that autonomous transactions may not have been possible
within the kernel earlier. I always think that the SCN mechanism is
like a sequence and has been around since before Oracle6 but
sequences were available to us only in Oracle6.
Hemant
At 06:54 AM 23-01-03 -0800, you wrote:
Well, then even Tom's vague on this one.
"DDL locks are automatically placed against objects during a DDL operation
to protect them from changes by other sessions".
Well, then even an insert statement makes changes to DD objects. Ain't
locks taken then?
"DDL Starts by commiting".
Why not declare a savepoint, and later, rollback to that savepoint?
And theres another DBA friend, who speculates that the reason could be that
DDL statements always take an exclusive lock on the underlying object. If
that transaction is not ended implicitly, the locks would be waiting
forever until the user intervenes. This could have serious consequences on
the database, with a potential for deadlocks. Ahem. This by far, seems to
be the most convincing answer to me.
Ok. Maybe, thats just the way its coded. The point I have understood from
this thread, is that a commit is performed to protect the data dictionary.
And DML statements are not truly atomic, for while it maybe possible for an
DML statement to roll back, there are some changes that are indeed
committed.
Thanks
Raj
"Deshpande,
Kirti"
rizon.com> cc:
Sent by: Subject: RE: simple
question on DDL
[EMAIL PROTECTED]
January 22,
2003
10:33
PM
Please respond
to
ORACLE-L
Dan addressed this very well in his earlier post...
Here is what Tom Kyte says in his book (Expert one-on-one Oracle):
"DDL locks are automatically placed against objects during a DDL operation
to protect them from changes by other sessions".
"DDL locks are held for the duration of the DDL statement, and are released
immediately afterwards. This is done, in effect, by always wrapping DDL
statements in implicit commits (or commit/rollback pair). It is for this
reason that DDL always commits in Oracle.".
"So, DDL will always commit, even if it is unsuccessful. DDL starts by
committing - be aware of this. It commits first so that if it has to
rollback, it will not roll back your transaction. If you execute DDL, it'll
make permanent any outstanding work you have performed, even if the DDL is
not successful.".
Refer to page 119...
- Kirti
-Original Message-
Sent: Wednesday, January 22, 2003 8:14 PM
To: Multiple recipients of list ORACLE-L
Dan,
If I may, essentially you are saying that changes to data dictionary tables
have to be committed immediately regardless of the outcome of the
transaction.
For instance in the following code, starting with an empty table t1
step 1: insert into table t1 values row1
step 2: create table t2
step 3: insert into table t1 values row2
step 4: rollback
At this point a select * from t1 will show only row1, since the ddl create
table t2 has inserted a commit. However, the point is, my transaction
should
have been from step 1 through step 4, not fromn step 3 through 4. The DDL
broke my txn at step 2 and another transaction started from there. The data
dictionary tables were updated and they should be committed; but that
commit
could have been done via an "autonomous transaction", not in the same
transaction the user issued.
The more I think about it, I see no point why a DDL should insert a commit.
This is different from saying that DDL itself may issue a commit to its
seprate transaction to update the catalog. Any thoughts on that?
Arup
--
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RE: simple question on DDL
Well, then even Tom's vague on this one. "DDL locks are automatically placed against objects during a DDL operation to protect them from changes by other sessions". Well, then even an insert statement makes changes to DD objects. Ain't locks taken then? "DDL Starts by commiting". Why not declare a savepoint, and later, rollback to that savepoint? And theres another DBA friend, who speculates that the reason could be that DDL statements always take an exclusive lock on the underlying object. If that transaction is not ended implicitly, the locks would be waiting forever until the user intervenes. This could have serious consequences on the database, with a potential for deadlocks. Ahem. This by far, seems to be the most convincing answer to me. Ok. Maybe, thats just the way its coded. The point I have understood from this thread, is that a commit is performed to protect the data dictionary. And DML statements are not truly atomic, for while it maybe possible for an DML statement to roll back, there are some changes that are indeed committed. Thanks Raj "Deshpande, Kirti" rizon.com> cc: Sent by: Subject: RE: simple question on DDL [EMAIL PROTECTED] January 22, 2003 10:33 PM Please respond to ORACLE-L Dan addressed this very well in his earlier post... Here is what Tom Kyte says in his book (Expert one-on-one Oracle): "DDL locks are automatically placed against objects during a DDL operation to protect them from changes by other sessions". "DDL locks are held for the duration of the DDL statement, and are released immediately afterwards. This is done, in effect, by always wrapping DDL statements in implicit commits (or commit/rollback pair). It is for this reason that DDL always commits in Oracle.". "So, DDL will always commit, even if it is unsuccessful. DDL starts by committing - be aware of this. It commits first so that if it has to rollback, it will not roll back your transaction. If you execute DDL, it'll make permanent any outstanding work you have performed, even if the DDL is not successful.". Refer to page 119... - Kirti -Original Message- Sent: Wednesday, January 22, 2003 8:14 PM To: Multiple recipients of list ORACLE-L Dan, If I may, essentially you are saying that changes to data dictionary tables have to be committed immediately regardless of the outcome of the transaction. For instance in the following code, starting with an empty table t1 step 1: insert into table t1 values row1 step 2: create table t2 step 3: insert into table t1 values row2 step 4: rollback At this point a select * from t1 will show only row1, since the ddl create table t2 has inserted a commit. However, the point is, my transaction should have been from step 1 through step 4, not fromn step 3 through 4. The DDL broke my txn at step 2 and another transaction started from there. The data dictionary tables were updated and they should be committed; but that commit could have been done via an "autonomous transaction", not in the same transaction the user issued. The more I think about it, I see no point why a DDL should insert a commit. This is different from saying that DDL itself may issue a commit to its seprate transaction to update the catalog. Any thoughts on that? Arup -- Please see the official ORACLE-L FAQ: http://www.orafaq.net -- Author: INET: [EMAIL PROTECTED] Fat City Network Services-- 858-538-5051 http
RE: simple question on DDL
Arup, I see your point and agree that the DDL should be an autonomous tx. Perhaps an enhancement request is in order? Since Oracle has the autonomous tx code, integrating into the kernel should be considered...perhaps for Oracle 38i? In the absence of that change, I must disagree and say that ddl must issue a commit. If you look at a combination of your example and mine, the problem of waiting transactions still exists. In order to create a table, space must be allocated. Again, if fet$ contains only 1 row for the particular file where the table is to be created, there is a potential for a serious locking problem. Dan -Original Message- Sent: Wednesday, January 22, 2003 7:14 PM To: Multiple recipients of list ORACLE-L Dan, If I may, essentially you are saying that changes to data dictionary tables have to be committed immediately regardless of the outcome of the transaction. For instance in the following code, starting with an empty table t1 step 1: insert into table t1 values row1 step 2: create table t2 step 3: insert into table t1 values row2 step 4: rollback At this point a select * from t1 will show only row1, since the ddl create table t2 has inserted a commit. However, the point is, my transaction should have been from step 1 through step 4, not fromn step 3 through 4. The DDL broke my txn at step 2 and another transaction started from there. The data dictionary tables were updated and they should be committed; but that commit could have been done via an "autonomous transaction", not in the same transaction the user issued. The more I think about it, I see no point why a DDL should insert a commit. This is different from saying that DDL itself may issue a commit to its seprate transaction to update the catalog. Any thoughts on that? Arup >From: "Fink, Dan" <[EMAIL PROTECTED]> >Reply-To: [EMAIL PROTECTED] >To: Multiple recipients of list ORACLE-L <[EMAIL PROTECTED]> >Subject: RE: simple question on DDL >Date: Wed, 22 Jan 2003 14:18:57 -0800 >MIME-Version: 1.0 >Received: from newsfeed.cts.com ([209.68.248.164]) by >mc1-f3.law16.hotmail.com with Microsoft SMTPSVC(5.0.2195.5600); Wed, 22 Jan >2003 15:13:04 -0800 >Received: from fatcity.UUCP (uucp@localhost)by newsfeed.cts.com >(8.9.3/8.9.3) with UUCP id PAA16552;Wed, 22 Jan 2003 15:11:42 -0800 (PST) >Received: by fatcity.com (26-Feb-2001/v1.0g-b72/bab) via UUCP id 00537F3B; >Wed, 22 Jan 2003 14:18:57 -0800 >Message-ID: <[EMAIL PROTECTED]> >X-Comment: Oracle RDBMS Community Forum >X-Sender: "Fink, Dan" <[EMAIL PROTECTED]> >Sender: [EMAIL PROTECTED] >Errors-To: [EMAIL PROTECTED] >Organization: Fat City Network Services, San Diego, California >X-ListServer: v1.0g, build 72; ListGuru (c) 1996-2001 Bruce A. Bergman >Precedence: bulk >Return-Path: [EMAIL PROTECTED] >X-OriginalArrivalTime: 22 Jan 2003 23:13:04.0174 (UTC) >FILETIME=[D0E4CCE0:01C2C26B] > >Don't forget that extent allocation also affects the extent map for the >segment and possibly the high water mark. The hwm can be set without >allocating another extent and allocation of an extent may not alter the hwm >(if you manually allocate an extent). If I deallocate space from an object, >I will alter the rows in fet$ and uet$ but not update the hwm. Make sense? > >As for the ATOMICITY of the transaction, this is usually used to describe >the changes to data of interest. I don't think it is used to describe any >underlying data dictionary changes. Thus the answer is Yes (for 99% of the >Oracle techies) and No (for the 1% of us who really like to know exactly >what is going on under the covers). > >Thanks for a great question, it brought up a subject that I had never >thought about. Yee-Haw! I learned someting today! > >Cheers, >Dan > >-Original Message- >Sent: Wednesday, January 22, 2003 2:04 PM >To: Multiple recipients of list ORACLE-L > > > >Thanks Dan. The gist of your response was that all changes to the data >dictionary are immediately commited. Seems to make sense to me. Maybe, >thats one reason why one cannot free space below the high water mark. Coz >changes to UET$ has been committed, even though the data was rolled back. > >I sent an email to one of my senior DBA friends, posing the same question, >and he replied with a one liner "To make the transaction as ATOMIC as >possible - They either run completely, or not at all". Now, does that mean >the Insert, update and delete statements are not ATOMIC? For on a rollback, >changes to the data dictionary are commited, whereas the data is rolled >back. > >Thanks >Raj > > > > > > > "Fink, Dan" > > list >ORACLE-L <[EMAIL PROTECTED]> &g
Re: simple question on DDL
It could also have something to do with the status changes of objects that may be affected by the DDL, though I am speculating here. Jared On Thursday 23 January 2003 02:58, you wrote: > remember this "functionality" of committing before a DDL statement has > been around from the beginning. Autonomous transactions have not. It > may simply be a case of Oracle not getting around to adding that change > to the kernel code. > > Or, as Kirti quoted from Tom Kyte, that might just be the way they want > it to work. > > --- Arup Nanda <[EMAIL PROTECTED]> wrote: > > Dan, > > > > If I may, essentially you are saying that changes to data dictionary > > tables > > have to be committed immediately regardless of the outcome of the > > transaction. > > > > For instance in the following code, starting with an empty table t1 > > > > step 1: insert into table t1 values row1 > > step 2: create table t2 > > step 3: insert into table t1 values row2 > > step 4: rollback > > > > At this point a select * from t1 will show only row1, since the ddl > > create > > table t2 has inserted a commit. However, the point is, my transaction > > should > > have been from step 1 through step 4, not fromn step 3 through 4. The > > DDL > > broke my txn at step 2 and another transaction started from there. > > The data > > dictionary tables were updated and they should be committed; but that > > commit > > could have been done via an "autonomous transaction", not in the same > > > > transaction the user issued. > > > > The more I think about it, I see no point why a DDL should insert a > > commit. > > This is different from saying that DDL itself may issue a commit to > > its > > seprate transaction to update the catalog. Any thoughts on that? > > > > Arup > > > > >From: "Fink, Dan" <[EMAIL PROTECTED]> > > >Reply-To: [EMAIL PROTECTED] > > >To: Multiple recipients of list ORACLE-L <[EMAIL PROTECTED]> > > >Subject: RE: simple question on DDL > > >Date: Wed, 22 Jan 2003 14:18:57 -0800 > > >MIME-Version: 1.0 > > >Received: from newsfeed.cts.com ([209.68.248.164]) by > > >mc1-f3.law16.hotmail.com with Microsoft SMTPSVC(5.0.2195.5600); Wed, > > > > 22 Jan > > > > >2003 15:13:04 -0800 > > >Received: from fatcity.UUCP (uucp@localhost)by newsfeed.cts.com > > >(8.9.3/8.9.3) with UUCP id PAA16552;Wed, 22 Jan 2003 15:11:42 -0800 > > > > (PST) > > > > >Received: by fatcity.com (26-Feb-2001/v1.0g-b72/bab) via UUCP id > > > > 00537F3B; > > > > >Wed, 22 Jan 2003 14:18:57 -0800 > > >Message-ID: <[EMAIL PROTECTED]> > > >X-Comment: Oracle RDBMS Community Forum > > >X-Sender: "Fink, Dan" <[EMAIL PROTECTED]> > > >Sender: [EMAIL PROTECTED] > > >Errors-To: [EMAIL PROTECTED] > > >Organization: Fat City Network Services, San Diego, California > > >X-ListServer: v1.0g, build 72; ListGuru (c) 1996-2001 Bruce A. > > > > Bergman > > > > >Precedence: bulk > > >Return-Path: [EMAIL PROTECTED] > > >X-OriginalArrivalTime: 22 Jan 2003 23:13:04.0174 (UTC) > > >FILETIME=[D0E4CCE0:01C2C26B] > > > > > >Don't forget that extent allocation also affects the extent map for > > > > the > > > > >segment and possibly the high water mark. The hwm can be set without > > >allocating another extent and allocation of an extent may not alter > > > > the hwm > > > > >(if you manually allocate an extent). If I deallocate space from an > > > > object, > > > > >I will alter the rows in fet$ and uet$ but not update the hwm. Make > > > > sense? > > > > >As for the ATOMICITY of the transaction, this is usually used to > > > > describe > > > > >the changes to data of interest. I don't think it is used to > > > > describe any > > > > >underlying data dictionary changes. Thus the answer is Yes (for 99% > > > > of the > > > > >Oracle techies) and No (for the 1% of us who really like to know > > > > exactly > > > > >what is going on under the covers). > > > > > >Thanks for a great question, it brought up a subject that I had > > > > never > > > > >thought about. Yee-Haw! I learned someting today! > > > > > >Cheers, > > >Dan > > > > > >-Original Message- > &g
Re: simple question on DDL
le - They either run completely, or not at all". Now, does
that mean
the Insert, update and delete statements are not ATOMIC? For on a
rollback,
changes to the data dictionary are commited, whereas the data is
rolled
back.
Thanks
Raj
"Fink, Dan"
recipients of
list
ORACLE-L <[EMAIL PROTECTED]>
.com> cc:
Sent by: Subject: RE: simple
question
on
DDL
root@fatcity.
com
January 22,
2003 02:16 PM
Please
respond to
ORACLE-L
Take the case of an insert (we'll call tx1), where space allocation
is
required. As you insert records, the table allocated additional
extents
(updating fet$ (free extent table) and uet$ (used extent table) in
the data
dictionary). These updates to the data dictionary are implicitly
committed,
even if you issue an explicit rollback for the insert statement.
Imagine if
the dd changes are not immediately committed. Let's say another tx
(we'll
call tx2) needs to allocate an extent in the same datafile. If fet$
contains only a single row for the file requested, then tx1 will
have an
exclusive lock on the row. tx2 needs to also lock the row
exclusively in
order to update it. Thus, tx2 would wait until tx1 has completed and
released the lock. In the meantime, any transaction that needs to
allocate
a
new extent in that file will have to wait...and wait...and wait.
A different strategy is to commit the changes to fet$ and uet$
immediately.
Then the next tx can access the row and grab space. While this could
result
in an overallocation of space if the tx is rolled back, it does not
block
other txs. If space was allocated to an object, and the tx failed,
there is
a strong probability that this space will be used at some point in
the
future.
It seems that the tradeoff here is that the access to the data
dictionary
=== message truncated ===
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RE: simple question on DDL
remember this "functionality" of committing before a DDL statement has been around from the beginning. Autonomous transactions have not. It may simply be a case of Oracle not getting around to adding that change to the kernel code. Or, as Kirti quoted from Tom Kyte, that might just be the way they want it to work. --- Arup Nanda <[EMAIL PROTECTED]> wrote: > Dan, > > If I may, essentially you are saying that changes to data dictionary > tables > have to be committed immediately regardless of the outcome of the > transaction. > > For instance in the following code, starting with an empty table t1 > > step 1: insert into table t1 values row1 > step 2: create table t2 > step 3: insert into table t1 values row2 > step 4: rollback > > At this point a select * from t1 will show only row1, since the ddl > create > table t2 has inserted a commit. However, the point is, my transaction > should > have been from step 1 through step 4, not fromn step 3 through 4. The > DDL > broke my txn at step 2 and another transaction started from there. > The data > dictionary tables were updated and they should be committed; but that > commit > could have been done via an "autonomous transaction", not in the same > > transaction the user issued. > > The more I think about it, I see no point why a DDL should insert a > commit. > This is different from saying that DDL itself may issue a commit to > its > seprate transaction to update the catalog. Any thoughts on that? > > Arup > > >From: "Fink, Dan" <[EMAIL PROTECTED]> > >Reply-To: [EMAIL PROTECTED] > >To: Multiple recipients of list ORACLE-L <[EMAIL PROTECTED]> > >Subject: RE: simple question on DDL > >Date: Wed, 22 Jan 2003 14:18:57 -0800 > >MIME-Version: 1.0 > >Received: from newsfeed.cts.com ([209.68.248.164]) by > >mc1-f3.law16.hotmail.com with Microsoft SMTPSVC(5.0.2195.5600); Wed, > 22 Jan > >2003 15:13:04 -0800 > >Received: from fatcity.UUCP (uucp@localhost)by newsfeed.cts.com > >(8.9.3/8.9.3) with UUCP id PAA16552;Wed, 22 Jan 2003 15:11:42 -0800 > (PST) > >Received: by fatcity.com (26-Feb-2001/v1.0g-b72/bab) via UUCP id > 00537F3B; > >Wed, 22 Jan 2003 14:18:57 -0800 > >Message-ID: <[EMAIL PROTECTED]> > >X-Comment: Oracle RDBMS Community Forum > >X-Sender: "Fink, Dan" <[EMAIL PROTECTED]> > >Sender: [EMAIL PROTECTED] > >Errors-To: [EMAIL PROTECTED] > >Organization: Fat City Network Services, San Diego, California > >X-ListServer: v1.0g, build 72; ListGuru (c) 1996-2001 Bruce A. > Bergman > >Precedence: bulk > >Return-Path: [EMAIL PROTECTED] > >X-OriginalArrivalTime: 22 Jan 2003 23:13:04.0174 (UTC) > >FILETIME=[D0E4CCE0:01C2C26B] > > > >Don't forget that extent allocation also affects the extent map for > the > >segment and possibly the high water mark. The hwm can be set without > >allocating another extent and allocation of an extent may not alter > the hwm > >(if you manually allocate an extent). If I deallocate space from an > object, > >I will alter the rows in fet$ and uet$ but not update the hwm. Make > sense? > > > >As for the ATOMICITY of the transaction, this is usually used to > describe > >the changes to data of interest. I don't think it is used to > describe any > >underlying data dictionary changes. Thus the answer is Yes (for 99% > of the > >Oracle techies) and No (for the 1% of us who really like to know > exactly > >what is going on under the covers). > > > >Thanks for a great question, it brought up a subject that I had > never > >thought about. Yee-Haw! I learned someting today! > > > >Cheers, > >Dan > > > >-Original Message- > >Sent: Wednesday, January 22, 2003 2:04 PM > >To: Multiple recipients of list ORACLE-L > > > > > > > >Thanks Dan. The gist of your response was that all changes to the > data > >dictionary are immediately commited. Seems to make sense to me. > Maybe, > >thats one reason why one cannot free space below the high water > mark. Coz > >changes to UET$ has been committed, even though the data was rolled > back. > > > >I sent an email to one of my senior DBA friends, posing the same > question, > >and he replied with a one liner "To make the transaction as ATOMIC > as > >possible - They either run completely, or not at all". Now, does > that mean > >the Insert, update and delete statements are not ATOMIC? For on a > rollback, > >changes to the data dictionary are commited, whereas the d
Re: simple question on DDL
SORRY - this was the wrong list. the other pertinent list is one about controlling machines via a DDL protocol and a demon called the alike. kr mr >>> [EMAIL PROTECTED] 01/22/03 16:49 PM >>> hi what's your exact question? you mean autocommit like in database applications? what tool are you using to observe or redard to this phenomenon? the erd-demon has to send some info via rs232 to make the amplifier -called booster - work. no info implies no current on the tracks. kind of answwer you want? kr mr >>> [EMAIL PROTECTED] 01/22/03 13:03 PM >>> Hi friends Why DDL statements performs auto commit ? What is the exact reason behind that one? Anyone can share his/her opinions!! Thanks & regards BanarasiBabu -- Please see the official ORACLE-L FAQ: http://www.orafaq.net -- Author: BanarasiBabu Tippa INET: [EMAIL PROTECTED] Fat City Network Services-- 858-538-5051 http://www.fatcity.com San Diego, California-- Mailing list and web hosting services - To REMOVE yourself from this mailing list, send an E-Mail message to: [EMAIL PROTECTED] (note EXACT spelling of 'ListGuru') and in the message BODY, include a line containing: UNSUB ORACLE-L (or the name of mailing list you want to be removed from). You may also send the HELP command for other information (like subscribing). -- Please see the official ORACLE-L FAQ: http://www.orafaq.net -- Author: Markus Reger INET: [EMAIL PROTECTED] Fat City Network Services-- 858-538-5051 http://www.fatcity.com San Diego, California-- Mailing list and web hosting services - To REMOVE yourself from this mailing list, send an E-Mail message to: [EMAIL PROTECTED] (note EXACT spelling of 'ListGuru') and in the message BODY, include a line containing: UNSUB ORACLE-L (or the name of mailing list you want to be removed from). You may also send the HELP command for other information (like subscribing). -- Please see the official ORACLE-L FAQ: http://www.orafaq.net -- Author: Markus Reger INET: [EMAIL PROTECTED] Fat City Network Services-- 858-538-5051 http://www.fatcity.com San Diego, California-- Mailing list and web hosting services - To REMOVE yourself from this mailing list, send an E-Mail message to: [EMAIL PROTECTED] (note EXACT spelling of 'ListGuru') and in the message BODY, include a line containing: UNSUB ORACLE-L (or the name of mailing list you want to be removed from). You may also send the HELP command for other information (like subscribing).
RE: simple question on DDL
Dan addressed this very well in his earlier post... Here is what Tom Kyte says in his book (Expert one-on-one Oracle): "DDL locks are automatically placed against objects during a DDL operation to protect them from changes by other sessions". "DDL locks are held for the duration of the DDL statement, and are released immediately afterwards. This is done, in effect, by always wrapping DDL statements in implicit commits (or commit/rollback pair). It is for this reason that DDL always commits in Oracle.". "So, DDL will always commit, even if it is unsuccessful. DDL starts by committing - be aware of this. It commits first so that if it has to rollback, it will not roll back your transaction. If you execute DDL, it'll make permanent any outstanding work you have performed, even if the DDL is not successful.". Refer to page 119... - Kirti -Original Message- Sent: Wednesday, January 22, 2003 8:14 PM To: Multiple recipients of list ORACLE-L Dan, If I may, essentially you are saying that changes to data dictionary tables have to be committed immediately regardless of the outcome of the transaction. For instance in the following code, starting with an empty table t1 step 1: insert into table t1 values row1 step 2: create table t2 step 3: insert into table t1 values row2 step 4: rollback At this point a select * from t1 will show only row1, since the ddl create table t2 has inserted a commit. However, the point is, my transaction should have been from step 1 through step 4, not fromn step 3 through 4. The DDL broke my txn at step 2 and another transaction started from there. The data dictionary tables were updated and they should be committed; but that commit could have been done via an "autonomous transaction", not in the same transaction the user issued. The more I think about it, I see no point why a DDL should insert a commit. This is different from saying that DDL itself may issue a commit to its seprate transaction to update the catalog. Any thoughts on that? Arup -- Please see the official ORACLE-L FAQ: http://www.orafaq.net -- Author: Deshpande, Kirti INET: [EMAIL PROTECTED] Fat City Network Services-- 858-538-5051 http://www.fatcity.com San Diego, California-- Mailing list and web hosting services - To REMOVE yourself from this mailing list, send an E-Mail message to: [EMAIL PROTECTED] (note EXACT spelling of 'ListGuru') and in the message BODY, include a line containing: UNSUB ORACLE-L (or the name of mailing list you want to be removed from). You may also send the HELP command for other information (like subscribing).
RE: simple question on DDL
Dan,
If I may, essentially you are saying that changes to data dictionary tables
have to be committed immediately regardless of the outcome of the
transaction.
For instance in the following code, starting with an empty table t1
step 1: insert into table t1 values row1
step 2: create table t2
step 3: insert into table t1 values row2
step 4: rollback
At this point a select * from t1 will show only row1, since the ddl create
table t2 has inserted a commit. However, the point is, my transaction should
have been from step 1 through step 4, not fromn step 3 through 4. The DDL
broke my txn at step 2 and another transaction started from there. The data
dictionary tables were updated and they should be committed; but that commit
could have been done via an "autonomous transaction", not in the same
transaction the user issued.
The more I think about it, I see no point why a DDL should insert a commit.
This is different from saying that DDL itself may issue a commit to its
seprate transaction to update the catalog. Any thoughts on that?
Arup
From: "Fink, Dan" <[EMAIL PROTECTED]>
Reply-To: [EMAIL PROTECTED]
To: Multiple recipients of list ORACLE-L <[EMAIL PROTECTED]>
Subject: RE: simple question on DDL
Date: Wed, 22 Jan 2003 14:18:57 -0800
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Don't forget that extent allocation also affects the extent map for the
segment and possibly the high water mark. The hwm can be set without
allocating another extent and allocation of an extent may not alter the hwm
(if you manually allocate an extent). If I deallocate space from an object,
I will alter the rows in fet$ and uet$ but not update the hwm. Make sense?
As for the ATOMICITY of the transaction, this is usually used to describe
the changes to data of interest. I don't think it is used to describe any
underlying data dictionary changes. Thus the answer is Yes (for 99% of the
Oracle techies) and No (for the 1% of us who really like to know exactly
what is going on under the covers).
Thanks for a great question, it brought up a subject that I had never
thought about. Yee-Haw! I learned someting today!
Cheers,
Dan
-Original Message-
Sent: Wednesday, January 22, 2003 2:04 PM
To: Multiple recipients of list ORACLE-L
Thanks Dan. The gist of your response was that all changes to the data
dictionary are immediately commited. Seems to make sense to me. Maybe,
thats one reason why one cannot free space below the high water mark. Coz
changes to UET$ has been committed, even though the data was rolled back.
I sent an email to one of my senior DBA friends, posing the same question,
and he replied with a one liner "To make the transaction as ATOMIC as
possible - They either run completely, or not at all". Now, does that mean
the Insert, update and delete statements are not ATOMIC? For on a rollback,
changes to the data dictionary are commited, whereas the data is rolled
back.
Thanks
Raj
"Fink, Dan"
ORACLE-L <[EMAIL PROTECTED]>
.com> cc:
Sent by: Subject: RE: simple question
on
DDL
root@fatcity.
com
January 22,
2003 02:16 PM
Please
respond to
ORACLE-L
Take the case of an insert (we'll call tx1), where space allocation is
required. As you insert records, the table allocated additional extents
(updating fet$ (free extent table) and uet$ (used extent table) in the data
dictionary). These updates to the data dictionary are implicitly committed,
even if you issue an explicit rollback for the insert statement. Imagine if
the dd changes are not immediately committed. Let's say another tx (we'll
call tx2) needs to allocate an extent in the same datafile. If fet$
contains only a single row for the file requested, then tx1 will have an
exclusive lock on the row. tx2 needs to also lock the row exclusively in
order to update it. Thus, tx2 would
RE: simple question on DDL
Don't forget that extent allocation also affects the extent map for the segment and possibly the high water mark. The hwm can be set without allocating another extent and allocation of an extent may not alter the hwm (if you manually allocate an extent). If I deallocate space from an object, I will alter the rows in fet$ and uet$ but not update the hwm. Make sense? As for the ATOMICITY of the transaction, this is usually used to describe the changes to data of interest. I don't think it is used to describe any underlying data dictionary changes. Thus the answer is Yes (for 99% of the Oracle techies) and No (for the 1% of us who really like to know exactly what is going on under the covers). Thanks for a great question, it brought up a subject that I had never thought about. Yee-Haw! I learned someting today! Cheers, Dan -Original Message- Sent: Wednesday, January 22, 2003 2:04 PM To: Multiple recipients of list ORACLE-L Thanks Dan. The gist of your response was that all changes to the data dictionary are immediately commited. Seems to make sense to me. Maybe, thats one reason why one cannot free space below the high water mark. Coz changes to UET$ has been committed, even though the data was rolled back. I sent an email to one of my senior DBA friends, posing the same question, and he replied with a one liner "To make the transaction as ATOMIC as possible - They either run completely, or not at all". Now, does that mean the Insert, update and delete statements are not ATOMIC? For on a rollback, changes to the data dictionary are commited, whereas the data is rolled back. Thanks Raj "Fink, Dan" .com>cc: Sent by: Subject: RE: simple question on DDL root@fatcity. com January 22, 2003 02:16 PM Please respond to ORACLE-L Take the case of an insert (we'll call tx1), where space allocation is required. As you insert records, the table allocated additional extents (updating fet$ (free extent table) and uet$ (used extent table) in the data dictionary). These updates to the data dictionary are implicitly committed, even if you issue an explicit rollback for the insert statement. Imagine if the dd changes are not immediately committed. Let's say another tx (we'll call tx2) needs to allocate an extent in the same datafile. If fet$ contains only a single row for the file requested, then tx1 will have an exclusive lock on the row. tx2 needs to also lock the row exclusively in order to update it. Thus, tx2 would wait until tx1 has completed and released the lock. In the meantime, any transaction that needs to allocate a new extent in that file will have to wait...and wait...and wait. A different strategy is to commit the changes to fet$ and uet$ immediately. Then the next tx can access the row and grab space. While this could result in an overallocation of space if the tx is rolled back, it does not block other txs. If space was allocated to an object, and the tx failed, there is a strong probability that this space will be used at some point in the future. It seems that the tradeoff here is that the access to the data dictionary is kept to a minimum duration at the expense of periodic space wastage (initially). As for the other data dictionary tables, it may be a case of read consistency conflicts. If a long running transaction needs to access a table definition, but a previous transaction has updated the table definition, but not committed, which table definition do you use? There are some issues with definitions not being the same at the start of a transaction and at a later point. As I recall, Oracle terminates the transaction if object definitions change while the transaction is running. All in all, it makes sense (at least to me) that changes to the data dictionary are immediately committed. Otherwise, the performance and integrity of the system would be comprimised. Dan Fink -Original Message- Sent: Wednesday, January 22, 2003 10:01 AM To: Multiple recipients of list ORACLE-L That raises another doubt. For an simple insert statement, could also update the UET$ or FET$ tables? So, if the purpose was to preserve all changes to the data dictionary, What's different between OBJ$, COL$ and these space management tables? Thanks Raj -- Please see the official ORACLE-L FAQ: http://www.orafaq.net -- Author: INET: [EMAIL PROTECTED] Fat City Network Services-- 858-538-5051 http://www.fatcity.com San Diego, California-- Mailing list and web hosting services - To REMOVE yourself from this mailing list, send an E-Mail
RE: simple question on DDL
Thanks Dan. The gist of your response was that all changes to the data dictionary are immediately commited. Seems to make sense to me. Maybe, thats one reason why one cannot free space below the high water mark. Coz changes to UET$ has been committed, even though the data was rolled back. I sent an email to one of my senior DBA friends, posing the same question, and he replied with a one liner "To make the transaction as ATOMIC as possible - They either run completely, or not at all". Now, does that mean the Insert, update and delete statements are not ATOMIC? For on a rollback, changes to the data dictionary are commited, whereas the data is rolled back. Thanks Raj "Fink, Dan" .com>cc: Sent by: Subject: RE: simple question on DDL root@fatcity. com January 22, 2003 02:16 PM Please respond to ORACLE-L Take the case of an insert (we'll call tx1), where space allocation is required. As you insert records, the table allocated additional extents (updating fet$ (free extent table) and uet$ (used extent table) in the data dictionary). These updates to the data dictionary are implicitly committed, even if you issue an explicit rollback for the insert statement. Imagine if the dd changes are not immediately committed. Let's say another tx (we'll call tx2) needs to allocate an extent in the same datafile. If fet$ contains only a single row for the file requested, then tx1 will have an exclusive lock on the row. tx2 needs to also lock the row exclusively in order to update it. Thus, tx2 would wait until tx1 has completed and released the lock. In the meantime, any transaction that needs to allocate a new extent in that file will have to wait...and wait...and wait. A different strategy is to commit the changes to fet$ and uet$ immediately. Then the next tx can access the row and grab space. While this could result in an overallocation of space if the tx is rolled back, it does not block other txs. If space was allocated to an object, and the tx failed, there is a strong probability that this space will be used at some point in the future. It seems that the tradeoff here is that the access to the data dictionary is kept to a minimum duration at the expense of periodic space wastage (initially). As for the other data dictionary tables, it may be a case of read consistency conflicts. If a long running transaction needs to access a table definition, but a previous transaction has updated the table definition, but not committed, which table definition do you use? There are some issues with definitions not being the same at the start of a transaction and at a later point. As I recall, Oracle terminates the transaction if object definitions change while the transaction is running. All in all, it makes sense (at least to me) that changes to the data dictionary are immediately committed. Otherwise, the performance and integrity of the system would be comprimised. Dan Fink -Original Message- Sent: Wednesday, January 22, 2003 10:01 AM To: Multiple recipients of list ORACLE-L That raises another doubt. For an simple insert statement, could also update the UET$ or FET$ tables? So, if the purpose was to preserve all changes to the data dictionary, What's different between OBJ$, COL$ and these space management tables? Thanks Raj
Re: simple question on DDL
Very good case described. Igor Neyman, OCP DBA [EMAIL PROTECTED] - Original Message - To: "Multiple recipients of list ORACLE-L" <[EMAIL PROTECTED]> Sent: Wednesday, January 22, 2003 2:16 PM > Take the case of an insert (we'll call tx1), where space allocation is > required. As you insert records, the table allocated additional extents > (updating fet$ (free extent table) and uet$ (used extent table) in the data > dictionary). These updates to the data dictionary are implicitly committed, > even if you issue an explicit rollback for the insert statement. Imagine if > the dd changes are not immediately committed. Let's say another tx (we'll > call tx2) needs to allocate an extent in the same datafile. If fet$ > contains only a single row for the file requested, then tx1 will have an > exclusive lock on the row. tx2 needs to also lock the row exclusively in > order to update it. Thus, tx2 would wait until tx1 has completed and > released the lock. In the meantime, any transaction that needs to allocate a > new extent in that file will have to wait...and wait...and wait. > > A different strategy is to commit the changes to fet$ and uet$ immediately. > Then the next tx can access the row and grab space. While this could result > in an overallocation of space if the tx is rolled back, it does not block > other txs. If space was allocated to an object, and the tx failed, there is > a strong probability that this space will be used at some point in the > future. > > It seems that the tradeoff here is that the access to the data dictionary is > kept to a minimum duration at the expense of periodic space wastage > (initially). > > As for the other data dictionary tables, it may be a case of read > consistency conflicts. If a long running transaction needs to access a table > definition, but a previous transaction has updated the table definition, but > not committed, which table definition do you use? There are some issues with > definitions not being the same at the start of a transaction and at a later > point. As I recall, Oracle terminates the transaction if object definitions > change while the transaction is running. > > All in all, it makes sense (at least to me) that changes to the data > dictionary are immediately committed. Otherwise, the performance and > integrity of the system would be comprimised. > > Dan Fink > > -Original Message- > Sent: Wednesday, January 22, 2003 10:01 AM > To: Multiple recipients of list ORACLE-L > > > > That raises another doubt. For an simple insert statement, could also > update the UET$ or FET$ tables? So, if the purpose was to preserve all > changes to the data dictionary, What's different between OBJ$, COL$ and > these space management tables? > > Thanks > Raj > -- > Please see the official ORACLE-L FAQ: http://www.orafaq.net > -- > Author: Fink, Dan > INET: [EMAIL PROTECTED] > > Fat City Network Services-- 858-538-5051 http://www.fatcity.com > San Diego, California-- Mailing list and web hosting services > - > To REMOVE yourself from this mailing list, send an E-Mail message > to: [EMAIL PROTECTED] (note EXACT spelling of 'ListGuru') and in > the message BODY, include a line containing: UNSUB ORACLE-L > (or the name of mailing list you want to be removed from). You may > also send the HELP command for other information (like subscribing). > -- Please see the official ORACLE-L FAQ: http://www.orafaq.net -- Author: Igor Neyman INET: [EMAIL PROTECTED] Fat City Network Services-- 858-538-5051 http://www.fatcity.com San Diego, California-- Mailing list and web hosting services - To REMOVE yourself from this mailing list, send an E-Mail message to: [EMAIL PROTECTED] (note EXACT spelling of 'ListGuru') and in the message BODY, include a line containing: UNSUB ORACLE-L (or the name of mailing list you want to be removed from). You may also send the HELP command for other information (like subscribing).
RE: simple question on DDL
Take the case of an insert (we'll call tx1), where space allocation is required. As you insert records, the table allocated additional extents (updating fet$ (free extent table) and uet$ (used extent table) in the data dictionary). These updates to the data dictionary are implicitly committed, even if you issue an explicit rollback for the insert statement. Imagine if the dd changes are not immediately committed. Let's say another tx (we'll call tx2) needs to allocate an extent in the same datafile. If fet$ contains only a single row for the file requested, then tx1 will have an exclusive lock on the row. tx2 needs to also lock the row exclusively in order to update it. Thus, tx2 would wait until tx1 has completed and released the lock. In the meantime, any transaction that needs to allocate a new extent in that file will have to wait...and wait...and wait. A different strategy is to commit the changes to fet$ and uet$ immediately. Then the next tx can access the row and grab space. While this could result in an overallocation of space if the tx is rolled back, it does not block other txs. If space was allocated to an object, and the tx failed, there is a strong probability that this space will be used at some point in the future. It seems that the tradeoff here is that the access to the data dictionary is kept to a minimum duration at the expense of periodic space wastage (initially). As for the other data dictionary tables, it may be a case of read consistency conflicts. If a long running transaction needs to access a table definition, but a previous transaction has updated the table definition, but not committed, which table definition do you use? There are some issues with definitions not being the same at the start of a transaction and at a later point. As I recall, Oracle terminates the transaction if object definitions change while the transaction is running. All in all, it makes sense (at least to me) that changes to the data dictionary are immediately committed. Otherwise, the performance and integrity of the system would be comprimised. Dan Fink -Original Message- Sent: Wednesday, January 22, 2003 10:01 AM To: Multiple recipients of list ORACLE-L That raises another doubt. For an simple insert statement, could also update the UET$ or FET$ tables? So, if the purpose was to preserve all changes to the data dictionary, What's different between OBJ$, COL$ and these space management tables? Thanks Raj -- Please see the official ORACLE-L FAQ: http://www.orafaq.net -- Author: Fink, Dan INET: [EMAIL PROTECTED] Fat City Network Services-- 858-538-5051 http://www.fatcity.com San Diego, California-- Mailing list and web hosting services - To REMOVE yourself from this mailing list, send an E-Mail message to: [EMAIL PROTECTED] (note EXACT spelling of 'ListGuru') and in the message BODY, include a line containing: UNSUB ORACLE-L (or the name of mailing list you want to be removed from). You may also send the HELP command for other information (like subscribing).
Re: simple question on DDL
Very good point, Raj. I didn't wonder just for the sake it; there was meat to it ;) Now that this has been raised, any ideas, anybody? - Original Message - To: "Multiple recipients of list ORACLE-L" <[EMAIL PROTECTED]> Sent: Wednesday, January 22, 2003 12:01 PM > > That raises another doubt. For an simple insert statement, could also > update the UET$ or FET$ tables? So, if the purpose was to preserve all > changes to the data dictionary, What's different between OBJ$, COL$ and > these space management tables? > > Thanks > Raj > > > > > > "Arup Nanda" > > tmail.com> cc: > Sent by: Subject: Re: simple question on DDL > root@fatcity. > com > > > January 22, > 2003 09:58 AM > Please > respond to > ORACLE-L > > > > > > > My guess will be to preserve the changes to the data dictionary, which are > just Oracle tables anyway. When you create a table, a record goes to TAB$, > SEG$ and so on and so forth. Unless there is a commit these information is > not visible. > > But now that you asked, I wnder why the same objective couldn't have been > done through autonomous transactions. > > Arup > > - Original Message - > To: "Multiple recipients of list ORACLE-L" <[EMAIL PROTECTED]> > Sent: Wednesday, January 22, 2003 6:33 AM > > > > Hi friends > > > > Why DDL statements performs auto commit ? What is the exact reason behind > > that one? > > Anyone can share his/her opinions!! > > > > Thanks & regards > > BanarasiBabu > > -- > > > -- > Please see the official ORACLE-L FAQ: http://www.orafaq.net > -- > Author: > INET: [EMAIL PROTECTED] > > Fat City Network Services-- 858-538-5051 http://www.fatcity.com > San Diego, California-- Mailing list and web hosting services > - > To REMOVE yourself from this mailing list, send an E-Mail message > to: [EMAIL PROTECTED] (note EXACT spelling of 'ListGuru') and in > the message BODY, include a line containing: UNSUB ORACLE-L > (or the name of mailing list you want to be removed from). You may > also send the HELP command for other information (like subscribing). > -- Please see the official ORACLE-L FAQ: http://www.orafaq.net -- Author: Arup Nanda INET: [EMAIL PROTECTED] Fat City Network Services-- 858-538-5051 http://www.fatcity.com San Diego, California-- Mailing list and web hosting services - To REMOVE yourself from this mailing list, send an E-Mail message to: [EMAIL PROTECTED] (note EXACT spelling of 'ListGuru') and in the message BODY, include a line containing: UNSUB ORACLE-L (or the name of mailing list you want to be removed from). You may also send the HELP command for other information (like subscribing).
RE: simple question on DDL
Consistency is the key too imagine what would happen if I dropped a column or changed it's definition, while a SQL statement or PL/SQL package was executing. The data that was updated before the change may well be very different in nature than the data after the change Borrowing from Ghostbusters if I may: Dr. DBA: This database is about to face a disaster of biblical proportions. Hapless Manager: What do you mean, "biblical?" Sr. DBA Lead: We mean real wrath-of-God type stuff. Plagues, darkness-- Another DBA: The dead rising from the grave! Sr. DBA: Forty years of darkness! Earthquakes, volcanoes-- Dr. DBA: Riots in the streets, dogs and cats living together, mass hysteria Manager: So, it's Ok to cut the DBA budget then? RF Robert G. Freeman Technical Management Consultant TUSC - The Oracle Experts www.tusc.com 904.708.5076 Cell (it's everywhere that I am!) Author of several books you can find on Amazon.com! -Original Message- Sent: Wednesday, January 22, 2003 10:49 AM To: Multiple recipients of list ORACLE-L Well look at it this way, besides creating/modifying/dropping the object that you want your also performing a number of updated/inserts/deletes from the data dictionary. Those data dictionary tables are just that, tables. Now imagine what a mess would be created if you performed a DDL statement and then rolled back the data dictionary updates? These MUST be completed as a single autonomous transaction, so Oracle does you a favor and performs an implicit commit. Same thing with any other DBMS I've been associated with. Dick Goulet Reply Separator Author: BanarasiBabu Tippa <[EMAIL PROTECTED]> Date: 1/22/2003 3:33 AM Hi friends Why DDL statements performs auto commit ? What is the exact reason behind that one? Anyone can share his/her opinions!! Thanks & regards BanarasiBabu -- Please see the official ORACLE-L FAQ: http://www.orafaq.net -- Author: BanarasiBabu Tippa INET: [EMAIL PROTECTED] Fat City Network Services-- 858-538-5051 http://www.fatcity.com San Diego, California-- Mailing list and web hosting services - To REMOVE yourself from this mailing list, send an E-Mail message to: [EMAIL PROTECTED] (note EXACT spelling of 'ListGuru') and in the message BODY, include a line containing: UNSUB ORACLE-L (or the name of mailing list you want to be removed from). You may also send the HELP command for other information (like subscribing). -- Please see the official ORACLE-L FAQ: http://www.orafaq.net -- Author: INET: [EMAIL PROTECTED] Fat City Network Services-- 858-538-5051 http://www.fatcity.com San Diego, California-- Mailing list and web hosting services - To REMOVE yourself from this mailing list, send an E-Mail message to: [EMAIL PROTECTED] (note EXACT spelling of 'ListGuru') and in the message BODY, include a line containing: UNSUB ORACLE-L (or the name of mailing list you want to be removed from). You may also send the HELP command for other information (like subscribing). -- Please see the official ORACLE-L FAQ: http://www.orafaq.net -- Author: Freeman Robert - IL INET: [EMAIL PROTECTED] Fat City Network Services-- 858-538-5051 http://www.fatcity.com San Diego, California-- Mailing list and web hosting services - To REMOVE yourself from this mailing list, send an E-Mail message to: [EMAIL PROTECTED] (note EXACT spelling of 'ListGuru') and in the message BODY, include a line containing: UNSUB ORACLE-L (or the name of mailing list you want to be removed from). You may also send the HELP command for other information (like subscribing).
Re: simple question on DDL
That raises another doubt. For an simple insert statement, could also update the UET$ or FET$ tables? So, if the purpose was to preserve all changes to the data dictionary, What's different between OBJ$, COL$ and these space management tables? Thanks Raj "Arup Nanda" tmail.com> cc: Sent by: Subject: Re: simple question on DDL root@fatcity. com January 22, 2003 09:58 AM Please respond to ORACLE-L My guess will be to preserve the changes to the data dictionary, which are just Oracle tables anyway. When you create a table, a record goes to TAB$, SEG$ and so on and so forth. Unless there is a commit these information is not visible. But now that you asked, I wnder why the same objective couldn't have been done through autonomous transactions. Arup - Original Message - To: "Multiple recipients of list ORACLE-L" <[EMAIL PROTECTED]> Sent: Wednesday, January 22, 2003 6:33 AM > Hi friends > > Why DDL statements performs auto commit ? What is the exact reason behind > that one? > Anyone can share his/her opinions!! > > Thanks & regards > BanarasiBabu > -- -- Please see the official ORACLE-L FAQ: http://www.orafaq.net -- Author: INET: [EMAIL PROTECTED] Fat City Network Services-- 858-538-5051 http://www.fatcity.com San Diego, California-- Mailing list and web hosting services - To REMOVE yourself from this mailing list, send an E-Mail message to: [EMAIL PROTECTED] (note EXACT spelling of 'ListGuru') and in the message BODY, include a line containing: UNSUB ORACLE-L (or the name of mailing list you want to be removed from). You may also send the HELP command for other information (like subscribing).
Re: simple question on DDL
My guess will be to preserve the changes to the data dictionary, which are just Oracle tables anyway. When you create a table, a record goes to TAB$, SEG$ and so on and so forth. Unless there is a commit these information is not visible. But now that you asked, I wnder why the same objective couldn't have been done through autonomous transactions. Arup - Original Message - To: "Multiple recipients of list ORACLE-L" <[EMAIL PROTECTED]> Sent: Wednesday, January 22, 2003 6:33 AM > Hi friends > > Why DDL statements performs auto commit ? What is the exact reason behind > that one? > Anyone can share his/her opinions!! > > Thanks & regards > BanarasiBabu > -- > Please see the official ORACLE-L FAQ: http://www.orafaq.net > -- > Author: BanarasiBabu Tippa > INET: [EMAIL PROTECTED] > > Fat City Network Services-- 858-538-5051 http://www.fatcity.com > San Diego, California-- Mailing list and web hosting services > - > To REMOVE yourself from this mailing list, send an E-Mail message > to: [EMAIL PROTECTED] (note EXACT spelling of 'ListGuru') and in > the message BODY, include a line containing: UNSUB ORACLE-L > (or the name of mailing list you want to be removed from). You may > also send the HELP command for other information (like subscribing). > -- Please see the official ORACLE-L FAQ: http://www.orafaq.net -- Author: Arup Nanda INET: [EMAIL PROTECTED] Fat City Network Services-- 858-538-5051 http://www.fatcity.com San Diego, California-- Mailing list and web hosting services - To REMOVE yourself from this mailing list, send an E-Mail message to: [EMAIL PROTECTED] (note EXACT spelling of 'ListGuru') and in the message BODY, include a line containing: UNSUB ORACLE-L (or the name of mailing list you want to be removed from). You may also send the HELP command for other information (like subscribing).
Re: simple question on DDL
hi what's your exact question? you mean autocommit like in database applications? what tool are you using to observe or redard to this phenomenon? the erd-demon has to send some info via rs232 to make the amplifier -called booster - work. no info implies no current on the tracks. kind of answwer you want? kr mr >>> [EMAIL PROTECTED] 01/22/03 13:03 PM >>> Hi friends Why DDL statements performs auto commit ? What is the exact reason behind that one? Anyone can share his/her opinions!! Thanks & regards BanarasiBabu -- Please see the official ORACLE-L FAQ: http://www.orafaq.net -- Author: BanarasiBabu Tippa INET: [EMAIL PROTECTED] Fat City Network Services-- 858-538-5051 http://www.fatcity.com San Diego, California-- Mailing list and web hosting services - To REMOVE yourself from this mailing list, send an E-Mail message to: [EMAIL PROTECTED] (note EXACT spelling of 'ListGuru') and in the message BODY, include a line containing: UNSUB ORACLE-L (or the name of mailing list you want to be removed from). You may also send the HELP command for other information (like subscribing). -- Please see the official ORACLE-L FAQ: http://www.orafaq.net -- Author: Markus Reger INET: [EMAIL PROTECTED] Fat City Network Services-- 858-538-5051 http://www.fatcity.com San Diego, California-- Mailing list and web hosting services - To REMOVE yourself from this mailing list, send an E-Mail message to: [EMAIL PROTECTED] (note EXACT spelling of 'ListGuru') and in the message BODY, include a line containing: UNSUB ORACLE-L (or the name of mailing list you want to be removed from). You may also send the HELP command for other information (like subscribing).
simple question on DDL
Hi friends Why DDL statements performs auto commit ? What is the exact reason behind that one? Anyone can share his/her opinions!! Thanks & regards BanarasiBabu -- Please see the official ORACLE-L FAQ: http://www.orafaq.net -- Author: BanarasiBabu Tippa INET: [EMAIL PROTECTED] Fat City Network Services-- 858-538-5051 http://www.fatcity.com San Diego, California-- Mailing list and web hosting services - To REMOVE yourself from this mailing list, send an E-Mail message to: [EMAIL PROTECTED] (note EXACT spelling of 'ListGuru') and in the message BODY, include a line containing: UNSUB ORACLE-L (or the name of mailing list you want to be removed from). You may also send the HELP command for other information (like subscribing).
