Обсуждение: tablelog

Hi,

I'm using tablelog (http://pgfoundry.org/projects/tablelog/) on an old
FreeBSD 6 / Postgresql 7.4 server, and I'm really happy with it. It
always worked great.

I saw this morning that the project used to be accepted for a while in
the debian packages repository, but has been removed last year:
http://www.mail-archive.com/debian-bugs-closed@lists.debian.org/msg19992
4.html. It looks like it is not really maintained anymore, but maybe it
does not need to?

Debian maintainers have a particularely bad opinion on this package:
"...nfortunatly development and package maintaining died short after. So
I ask for removal of this (buggy) package."

Is anyone using it with Postgresql 8.3? Or is there an alternative to
this?

While we are talking about this, is a development like Oracle "Flashback
queries" planned maybe?

----------------------
Philippe Lang
Attik System
Rte de la Fonderie 2
1700 Fribourg

Hello Philippe,

i'm the author of tablelog.


On Tue, 10 Feb 2009 11:52:13 +0100 Philippe Lang wrote:

> I'm using tablelog (http://pgfoundry.org/projects/tablelog/) on an old
> FreeBSD 6 / Postgresql 7.4 server, and I'm really happy with it. It
> always worked great.
>
> I saw this morning that the project used to be accepted for a while in
> the debian packages repository, but has been removed last year:
> http://www.mail-archive.com/debian-bugs-closed@lists.debian.org/msg19992
> 4.html. It looks like it is not really maintained anymore, but maybe it
> does not need to?

The software is still maintained, but not available as a Debian package
anymore. To be more exact: there's nothing i would add/change right now.
Last weekend i got an idea how to solve my showstopper for releasing
1.0 but i have to test if my idea might work at all.



> Debian maintainers have a particularely bad opinion on this package:
> "...nfortunatly development and package maintaining died short after. So
> I ask for removal of this (buggy) package."

It's only marked  buggy because it does not follow the guidelines for
PostgreSQL packages in Debian. The software itself is not buggy.



> Is anyone using it with Postgresql 8.3? Or is there an alternative to
> this?

The last version works with 8.3.



> While we are talking about this, is a development like Oracle "Flashback
> queries" planned maybe?

You can "flashback" to old data, but you need to use the tablelog
functions.


Bye

--
                Andreas 'ads' Scherbaum
German PostgreSQL User Group
European PostgreSQL User Group - Board of Directors

While we are talking about this, is a development like Oracle "Flashback
queries" planned maybe?   

You can "flashback" to old data, but you need to use the tablelog
functions. 

Oracle Flashback Query seems to use undo logs to return in a point in time if the undo retention param permit it. You can do it with a date, or with the SCN (system change number), a kind of transaction number. It saves you administration task and table management, and space.

Is this doable with PG, using some pg transaction logs?

More infos on oracle flashback nice feature:
http://www.oracle.com/technology/deploy/availability/htdocs/Flashback_Overview.htm

Bruno Lavoie

On Tue, 10 Feb 2009 11:36:38 -0500 Bruno Lavoie wrote:

> Oracle Flashback Query seems to use undo logs to return in a point in
> time if the undo retention param permit it. You can do it with a date,
> or with the SCN (system change number), a kind of transaction number. It
> saves you administration task and table management, and *space*.
>
> Is this doable with PG, using some pg transaction logs?

I think, the only way is to use PITR and roll the backup forward during
the exact point you want to see.

Probably another way - but really untested and dangerous - would be to
play around with the meta information for each row. But VACUUM makes
sure dead rows are removed very fast, so i think it's not even worth to
try out.


Bye

--
                Andreas 'ads' Scherbaum
German PostgreSQL User Group
European PostgreSQL User Group - Board of Directors

"Andreas 'ads' Scherbaum" <adsmail@wars-nicht.de> writes:
> On Tue, 10 Feb 2009 11:36:38 -0500 Bruno Lavoie wrote:
>> Oracle Flashback Query seems to use undo logs to return in a point in
>> time if the undo retention param permit it. You can do it with a date,
>> or with the SCN (system change number), a kind of transaction number. It
>> saves you administration task and table management, and *space*.
>>
>> Is this doable with PG, using some pg transaction logs?

> I think, the only way is to use PITR and roll the backup forward during
> the exact point you want to see.

contrib/spi/timetravel might be worth looking at too.  It hasn't been
touched in awhile but AFAIK it still works.

            regards, tom lane

Hi,

On Tuesday 10 February 2009 17:36:38 Bruno Lavoie wrote:
> Oracle Flashback Query seems to use undo logs to return in a point in
> time if the undo retention param permit it. You can do it with a date,
> or with the SCN (system change number), a kind of transaction number. It
> saves you administration task and table management, and *space*.
>
> Is this doable with PG, using some pg transaction logs?

It's been discussed recently:
  http://archives.postgresql.org/pgsql-hackers/2009-02/msg00117.php

No idea how this would compare to the timetravel contrib, though, only that
the mail refers to concepts yet to be proposed and implemented etc...

Regards,
--
dim