Horton

Thread

  1. [HACKERS] register creation date of table

    Willy-Bas Loos <willybas@gmail.com> — 2011-10-14T10:20:12Z

    Hi,

We have several users working on a 8.4 database, using it as a
back-end for several related apps and transfering data to and from it.
The database tends to get a bit messy, so i've made a little table to
provide an overview.
This table is truncated and refilled daily, it shows all tables and
views in the database and :
* the owner
* number of records (estimation)
* it's size on disk
* the description

There's a view on the table that shows the size as pg_size_pretty
When you edit the description in the table (or the view, but no
support in pgAdmin), the comment in the system tables is updated also.
I attatched my code, hope some people find it handy, sorry for the
names and comments being in dutch.

Now, i would like to improve this thing and add a creation date for the table.
I have some questions about that.
1. I think that there is no such information in the system tables. is
that correct?
I am planning to change the mechanism, so that the table is not
truncated, but new tables are inserted in the overview and dropped
tables are deleted from it. I need to do that in 2 steps (delete and
insert).
Then i can add a creation-date column which i will fill with 'today'.

2. i would like to go back in time. I think that i will just look up
the creation date for the files in the data directory and translate
their oid's to the object names and then update their dates. This
would of course only work from the last restore. Is that a good way to
do it?

Thanks,

WBL

-- 
"Patriotism is the conviction that your country is superior to all
others because you were born in it." -- George Bernard Shaw

  2. Re: [HACKERS] register creation date of table

    Guillaume Lelarge <guillaume@lelarge.info> — 2011-10-14T12:51:31Z

    Hi,

On Fri, 2011-10-14 at 12:20 +0200, Willy-Bas Loos wrote:
> [...]
> We have several users working on a 8.4 database, using it as a
> back-end for several related apps and transfering data to and from it.
> The database tends to get a bit messy, so i've made a little table to
> provide an overview.
> This table is truncated and refilled daily, it shows all tables and
> views in the database and :
> * the owner
> * number of records (estimation)
> * it's size on disk
> * the description
> 
> There's a view on the table that shows the size as pg_size_pretty
> When you edit the description in the table (or the view, but no
> support in pgAdmin), the comment in the system tables is updated also.
> I attatched my code, hope some people find it handy, sorry for the
> names and comments being in dutch.
> 

I'm not sure I understand your comment: "no support in pgAdmin". No
support for what?

> Now, i would like to improve this thing and add a creation date for the table.
> I have some questions about that.
> 1. I think that there is no such information in the system tables. is
> that correct?

Yes.


-- 
Guillaume
  http://blog.guillaume.lelarge.info
  http://www.dalibo.com

  3. Re: [HACKERS] register creation date of table

    Willy-Bas Loos <willybas@gmail.com> — 2011-10-14T12:55:42Z

    On Fri, Oct 14, 2011 at 2:51 PM, Guillaume Lelarge
<guillaume@lelarge.info> wrote:
>> When you edit the description in the table (or the view, but no
>> support in pgAdmin), the comment in the system tables is updated also.

> I'm not sure I understand your comment: "no support in pgAdmin". No
> support for what?

Editable views.
That's the reason that i made a table out of it instead of a view.
The "pretty" version is a view, but you can't edit the comment.

Cheers,

WBL

-- 
"Patriotism is the conviction that your country is superior to all
others because you were born in it." -- George Bernard Shaw

  4. Re: [HACKERS] register creation date of table

    Guillaume Lelarge <guillaume@lelarge.info> — 2011-10-14T13:38:51Z

    On Fri, 2011-10-14 at 14:55 +0200, Willy-Bas Loos wrote:
> On Fri, Oct 14, 2011 at 2:51 PM, Guillaume Lelarge
> <guillaume@lelarge.info> wrote:
> >> When you edit the description in the table (or the view, but no
> >> support in pgAdmin), the comment in the system tables is updated also.
> 
> > I'm not sure I understand your comment: "no support in pgAdmin". No
> > support for what?
> 
> Editable views.
> That's the reason that i made a table out of it instead of a view.
> The "pretty" version is a view, but you can't edit the comment.
> 

Not sure which pgAdmin release you use, but 1.14 can edit comments on an
already existing views.


-- 
Guillaume
  http://blog.guillaume.lelarge.info
  http://www.dalibo.com

  5. Re: [HACKERS] register creation date of table

    Willy-Bas Loos <willybas@gmail.com> — 2011-10-14T13:59:41Z

    On Fri, Oct 14, 2011 at 3:38 PM, Guillaume Lelarge
<guillaume@lelarge.info> wrote:
> Not sure which pgAdmin release you use, but 1.14 can edit comments on an
> already existing views.

Of course it supports editting comments on the view itself, but that's
not what i mean.
I have a view that shows the comments on all the tables in the database.
There is an _UPDATE rule on the view that would update the comment of
the other tables, but pgAdmin will not let me update any data in that
view.

Cheers,

WBL

-- 
"Patriotism is the conviction that your country is superior to all
others because you were born in it." -- George Bernard Shaw

  6. Re: [HACKERS] register creation date of table

    Guillaume Lelarge <guillaume@lelarge.info> — 2011-10-14T14:03:08Z

    On Fri, 2011-10-14 at 15:59 +0200, Willy-Bas Loos wrote:
> On Fri, Oct 14, 2011 at 3:38 PM, Guillaume Lelarge
> <guillaume@lelarge.info> wrote:
> > Not sure which pgAdmin release you use, but 1.14 can edit comments on an
> > already existing views.
> 
> Of course it supports editting comments on the view itself, but that's
> not what i mean.
> I have a view that shows the comments on all the tables in the database.
> There is an _UPDATE rule on the view that would update the comment of
> the other tables, but pgAdmin will not let me update any data in that
> view.
> 

Oh yes, that's right. Not much we can do about it.


-- 
Guillaume
  http://blog.guillaume.lelarge.info
  http://www.dalibo.com

  7. Re: [HACKERS] register creation date of table

    Robert Haas <robertmhaas@gmail.com> — 2011-10-15T10:51:35Z

    On Fri, Oct 14, 2011 at 6:20 AM, Willy-Bas Loos <willybas@gmail.com> wrote:
> 1. I think that there is no such information in the system tables. is
> that correct?

Yes.  It's been discussed before but some people (particularly, Tom,
IIRC) are not convinced that it's useful enough to justify its
existence.

> 2. i would like to go back in time. I think that i will just look up
> the creation date for the files in the data directory and translate
> their oid's to the object names and then update their dates. This
> would of course only work from the last restore. Is that a good way to
> do it?

Well, that timestamp will get bumped on TRUNCATE, CLUSTER, VACUUM
FULL, and rewriting versions of ALTER TABLE.

-- 
Robert Haas
EnterpriseDB: http://www.enterprisedb.com
The Enterprise PostgreSQL Company