There aren't any constraint or indexes, just a regular table.  I didn't see
the fsm and vm files in the base dir. Were they created immediately for
every table or after some updates/deletes ?

On Wed, Jan 30, 2019, 3:27 PM Jehan-Guillaume (ioguix) de Rorthais <
iog...@free.fr wrote:

> On Wed, 30 Jan 2019 14:19:52 +0100
> Tumasgiu Rossini <rossin...@gmail.com> wrote:
>
> > According to the doc [1],
> > pg_total_relation_size add toasted data *and* indexes to the mix.
>
> *and* FSM *and* VM.
>
> > Any index, unique constraint, or primary key on your table ?
> >
> > [1]
> >
> https://www.postgresql.org/docs/current/functions-admin.html#FUNCTIONS-ADMIN-DBSIZE
> >
> > Le mer. 30 janv. 2019 à 11:42, Mariel Cherkassky <
> > mariel.cherkas...@gmail.com> a écrit :
> >
> > > Hey,
> > > I'm using postgresql 9.6.11. I wanted to ask something about the
> functions
> > > I mentioned in the title :
> > > I created the next table :
> > > postgres=# \d students;
> > >       Table "public. students  "
> > >   Column  |  Type   | Modifiers
> > > ----------+---------+-----------
> > >  id| integer |
> > >  name| text    |
> > >  age| integer |
> > >  data     | jsonb   |
> > >
> > > I inserted one row. When I query the table`s size with
> > > pg_total_relation_size I see that the data occupies 2 pages :
> > >
> > > postgres=# select pg_total_relation_size(' students  ');
> > >  pg_total_relation_size
> > > ------------------------
> > >                   16384
> > > (1 row)
> > >
> > > postgres=# select pg_relation_size(' students  ');
> > >  pg_relation_size
> > > ------------------
> > >              8192
> > > (1 row)
> > >
> > > When I used pgstattuple :
> > > postgres=# select * from pgstattuple('pg_toast.pg_toast_1187222');
> > >  table_len | tuple_count | tuple_len | tuple_percent |
> dead_tuple_count |
> > > dead_tuple_len | dead_tuple_percent | free_space | free_percent
> > >
> > >
> -----------+-------------+-----------+---------------+------------------+----------------+--------------------+------------+--------------
> > >          0 |           0 |         0 |             0 |
> 0 |
> > >             0 |                  0 |          0 |            0
> > > (1 row)
> > >
> > > postgres=# select * from pgstattuple('students');
> > >  table_len | tuple_count | tuple_len | tuple_percent |
> dead_tuple_count |
> > > dead_tuple_len | dead_tuple_percent | free_space | free_percent
> > >
> > >
> -----------+-------------+-----------+---------------+------------------+----------------+--------------------+------------+--------------
> > >       8192 |           1 |      1221 |          14.9 |
> 0 |
> > >             0 |                  0 |       6936 |        84.67
> > > (1 row)
> > >
> > > Which means, the toasted table is empty and you can see that the row I
> > > inserted should occupy only one page(8K in my system).
> > >
> > > Then, why the pg_total_relation_size shows another page ?(16KB in
> total)
> > >
> > >
> > >
> > >
> > >
>
>
>
> --
> Jehan-Guillaume de Rorthais
> Dalibo
>

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