Re: metadata about creation and size of tables

On 10/2/18 1:38 PM, Martin Mueller wrote:
> I’ve looked at the documentation to find where to find some data that
> are very to find Mysql:  the creation and modification data of a table
> and the size of particular tables.
>
> Where do I find an answer to the question “which is the last table I
> created” or “when did I last modify this table?”  In the data directory,

Postgres does not track these times. You can search the list archives
for past discussions on the pros and cons.

> tables seem to have numbers, but there doesn’t seem to be an easy
> mapping of those numbers to the table names.
From:

https://www.postgresql.org/docs/10/static/functions-admin.html#FUNCTIONS-ADMIN-DBOBJECT

select pg_relation_filepath('id_test'), pg_relation_filenode('id_test');
pg_relation_filepath | pg_relation_filenode

----------------------+----------------------

base/733941/2976140 | 2976140

>
> I thumbed through the documentation, but didn’t see any heading that was
> likely to have that information.  Is there some where  a “table of
> tables” that lets you look up various metadata?

https://www.postgresql.org/docs/10/static/catalogs.html

For tables in particular:

https://www.postgresql.org/docs/10/static/catalog-pg-class.html

There is also:

https://www.postgresql.org/docs/10/static/information-schema.html

And in psql there are the \ commands:

https://www.postgresql.org/docs/10/static/app-psql.html

In psql \? will get you a list of these with descriptions

As an example:

test_(aklaver)> \d id_test
Table "public.id_test"
Column | Type | Collation | Nullable |
Default
--------+-------------------+-----------+----------+-------------------------------------
id | integer | | not null |
nextval('id_test_id_seq'::regclass)
fld_1 | character varying | | |
fld_2 | boolean | | |

test_(aklaver)> \d+ id_test
Table "public.id_test"
Column | Type | Collation | Nullable |
Default | Storage | Stats target | Description
--------+-------------------+-----------+----------+-------------------------------------+----------+--------------+-------------
id | integer | | not null |
nextval('id_test_id_seq'::regclass) | plain | |
fld_1 | character varying | | |
| extended | |
fld_2 | boolean | | |
| plain | |

--
Adrian Klaver
adrian(dot)klaver(at)aklaver(dot)com