Re: Add visibility map information to pg_freespace.

(2013/07/09 19:55), Kyotaro HORIGUCHI wrote:
> Hello, I've brought visibilitymap extentions for pg_freespacemap
> and pgstattuple.
>
> At Mon, 08 Jul 2013 16:59:05 +0900 (Tokyo Standard Time), Kyotaro HORIGUCHI <horiguchi.kyotaro@lab.ntt.co.jp> wrote
in<20130708.165905.118860769.horiguchi.kyotaro@lab.ntt.co.jp> 
>> I'll come again with the first implementation of it. And as for
>> pg_freespacemap, I'll keep the current direction - adding column
>> to present output records format of pg_freespace(). And
>> documentation, if possible.
>
> pg_freespace_vm_v2.patch:
>
>    Interface has been changed from the first patch. The version of
>    pg_freespace() provided with vm information is named
>    pg_freespace_with_vminfo() and shows output like following.
>
> | postgres=# select * from pg_freespace_with_vminfo('t'::regclass) limit 10;
> |  blkno | avail | is_all_visible
> | -------+-------+----------------
> |      0 |    64 | t
> |      1 |    32 | t
> |      2 |    96 | t
> |      3 |    64 | t
> |      4 |    96 | t
> |      5 |    96 | t
> |      6 |   128 | t
> |      7 |    32 | t
> |      8 |    96 | t

I think we can simply add is_all_viible column to the existing
pg_freespace(), because adding column would not break
backward-compatibility in general. Any other thoughts?

> pgstattuple_vm_v1.patch:
>
>    The first version of VM extension for pgstattuple. According to
>    the previous discussion, the added column is named
>    'all_visible_percent'.
>
> | postgres=# select * from pgstattuple('t');
> | -[ RECORD 1 ]-------+---------
> | table_len           | 71770112
> | tuple_count         | 989859
> | tuple_len           | 31675488
> | tuple_percent       | 44.13
> | dead_tuple_count    | 99
> | dead_tuple_len      | 3168
> | dead_tuple_percent  | 0
> | free_space          | 31886052
> | free_percent        | 44.43
> | all_visible_percent | 99.98

It seems working fine.

And I added a regression test for pg_freespacemap and additional
test cases for pgstattuple. Please take a look.

Regards,
--
Satoshi Nagayasu <snaga@uptime.jp>
Uptime Technologies, LLC. http://www.uptime.jp