To: pgsql-hackers@postgresql.org
From: Quan Zongliang <quanzongliang@yeah.net>
Subject: bugfix: when the blocksize is 32k, the function page_header of
 pageinspect returns negative numbers.
Message-ID: <8b8ec36e-61fe-14f9-005d-07bc85aa4eed@yeah.net>
Date: Thu, 8 Jul 2021 08:56:19 +0800
User-Agent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10.14; rv:78.0)
 Gecko/20100101 Thunderbird/78.11.0
MIME-Version: 1.0
Content-Type: multipart/mixed;
 boundary="------------9002C8B4F7ECE9FAA5B7830E"
Content-Language: en-US
Archived-At: 
 <https://www.postgresql.org/message-id/8b8ec36e-61fe-14f9-005d-07bc85aa4eed%40yeah.net>
Precedence: bulk

This is a multi-part message in MIME format.
--------------9002C8B4F7ECE9FAA5B7830E
Content-Type: text/plain; charset=utf-8; format=flowed
Content-Transfer-Encoding: 7bit


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)


--
Quan Zongliang

--------------9002C8B4F7ECE9FAA5B7830E
Content-Type: text/plain; charset=UTF-8; x-mac-type="0"; x-mac-creator="0";
 name="pageinspect.patch"
Content-Transfer-Encoding: base64
Content-Disposition: attachment;
 filename="pageinspect.patch"
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=
--------------9002C8B4F7ECE9FAA5B7830E--