Re: bugfix: when the blocksize is 32k, the function page_header of pageinspect returns negative numbers.

On Thu, Jul 8, 2021 at 6:26 AM Quan Zongliang <quanzongliang(at)yeah(dot)net> wrote:
>
> If the block size is 32k, the function page_header of the pageinspect
> module returns negative numbers:
>
> postgres=# select * from page_header(get_raw_page('t1',0));
> lsn | checksum | flags | lower | upper | special | pagesize |
> version | prune_xid
> -----------+----------+-------+-------+-------+---------+----------+---------+-----------
> 0/174CF58 | 0 | 0 | 28 | 32736 | -32768 | -32768 |
> 4 | 0
> (1 row)
>
>
> This patch changes the output parameters lower, upper, special and
> pagesize to int32.
>
> postgres=# select * from page_header(get_raw_page('t1',0));
> lsn | checksum | flags | lower | upper | special | pagesize |
> version | prune_xid
> -----------+----------+-------+-------+-------+---------+----------+---------+-----------
> 0/19EA640 | 0 | 0 | 28 | 32736 | 32768 | 32768 |
> 4 | 0
> (1 row)

+1. int32 makes sense because the maximum allowed block size is 32768
and smallint with range -32768 to +32767 can't hold it. Internally,
lower, upper, special are treated as unit16. I looked at the patch,
how about using "int4" instead of just "int", just for readability?
And, do we need to change in pageinspect--1.1--1.2.sql and
pageinspect--1.0--1.1.sql along with pageinspect--1.5.sql?

Regards,
Bharath Rupireddy.