Message-ID: <4c5dee3a-8381-4e0f-b882-d1bd950e8972@dalibo.com>
Date: Tue, 21 Jan 2025 17:01:06 +0100
MIME-Version: 1.0
User-Agent: Mozilla Thunderbird
Content-Language: fr
To: =?UTF-8?Q?Fr=C3=A9d=C3=A9ric_Yhuel?= <frederic.yhuel@dalibo.com>
Cc: pgsql-hackers@lists.postgresql.org
From: =?UTF-8?Q?Benoit_Lobr=C3=A9au?= <benoit.lobreau@dalibo.com>
Subject: doc: explain pgstatindex fragmentation
Autocrypt: addr=benoit.lobreau@dalibo.com; keydata=
 xsBNBF3FR7IBCADDvtR0p09SI9OvnbWw+VEvO5IXefBWFWefxrPd0H3Sf3gsBLiKbRdkSjvz
 2y+ksRgBUkhK1Kiqe/QuddgvuT9OUFBCrOtZxkBgJYRbxBNTOnIehhEoK9sdqjwvwNyxJUEX
 er1UgErP+MJTvwpW1J8Uq9oV+NbqgNQ7ca5G2D3x7DI2Tbbw0iu+lmCIdXQpTk7hacErGscC
 p/eaJQFd6EPAZPS7BQEgjuDDjGCy4RzTSiobtqn0ocaEj+w7365FVKKZD2LjEm1mfBK/4nml
 H/vlssXkKKpUGetaib6AVpZK3a0xBTMi04ft/V8iGGJuVhE45WjjKSckmeLafTZCGxN9ABEB
 AAHNK0Jlbm9pdCBMb2Jyw6lhdSA8YmVub2l0LmxvYnJlYXVAZGFsaWJvLmNvbT7CwJQEEwEI
 AD4CGwMFCwkIBwIGFQoJCAsCBBYCAwECHgECF4AWIQRkbHJAht3VPY+ptaDDJY+vq0O76wUC
 Za56QgUJC6uZkAAKCRDDJY+vq0O760ECCACDPj6p9VXaX4GF9p+3zhoDwxsUWh0xODwsK//h
 SBGsRmPaElApbOR5rs2WDFaPE95XG3Vdo2rno7i4mt0fASls7vq4P0BPJiPM4fKEr+kfXAxP
 2clqmkBMn2o+EEeUGDmnn3RAVzDDoyML6N/unpyOTHWfscxvvj6AKreUtxzQm0LVQRL+hIaG
 SAlcwpVWQBPhA6Roi1/7Uz9qm8nWjFOuV6vO5yVe0sfRrrO9AFkjBGFT/B06sSs33Os6Hjs5
 2ckLn5Gxlty8XgTpbaG0bJiV+GDTcXh5UV8XVKaMomOLJxWw8US6PSSqQxodWuJqsvlxXV93
 ae6cMIosHsriaUo5zsBNBF3FR7IBCADEWwsQar1qtLKdoAoqKThz+kQXu3UADQ0c8JCgsp+8
 a6hFDg+uIw0j852lkJOPHll414Qw+kLC1bUo7H6+mPHzko/aR3TFz6vvOrm0afwFP7sm9Vbe
 UbpeohnrXBBwb1PjNhDphaXeMVovJqSgRifhc/sAR6fXi+2OCrH+8CUYa0aHhwoecStgw/tm
 EDPZ8lCsg5IdyO5Er4ZMOl/EbaRuTOpl7U/GzJBQSYf7t4KHotIpEeuJVv4X/+nTW3ALG+dG
 pRA5GplNnlQNfsEymnT4W7RbfafDp7Q7nK6w7d55ZU8UyiS6N/1wh/DL1hntC65lQbHlmwNx
 RG132ecNOcqFABEBAAHCwHwEGAEIACYCGwwWIQRkbHJAht3VPY+ptaDDJY+vq0O76wUCZa56
 dQUJC6uZwwAKCRDDJY+vq0O76y9jB/0fVyz7D56D2A6MUGASNkh6IiuHCF/UgEfU0m5fC6pd
 38+fmyUMkGR3QwrtZP3SCLaBKT4LHxhVu7tEUWI+6WK7/s0Jsx5L8aIfDKY4zjqQ9InP+LkA
 azkKW4JpIb9Ny0FzRjUyf9gReU5nMy9sUNS4DhoHG6c/bQYqkj9uA5AokiDDCRg2dobfpaNP
 C6qQQIXD+wi0aZ4jR5r4rXMxmwFutandoaxDpPBj4EXlyRHhzyKfgb2c6TXdCVQ5YJUFUi9k
 gl7CXplN8vBpMuzN5y6NPd3Xekcp16D5XCQNBQ2drIsnFR4IbDPI1Mqd6OJYH0vum6g8FmoN
 s7ygc4oi12nU
Content-Type: text/plain; charset=UTF-8; format=flowed
Content-Transfer-Encoding: 8bit
Archived-At: <https://www.postgresql.org/message-id/4c5dee3a-8381-4e0f-b882-d1bd950e8972%40dalibo.com>
Precedence: bulk

Hi,

I like the clarification but I think that:

A higher <literal>leaf_fragmentation</literal> indicates that the 
physical order of the index leaf
pages increasingly deviates from their logical order.

Would be cleaner than:

The higher <literal>leaf_fragmentation</literal> is, the less the 
physical order
of the index leaf pages corresponds to the logical order we would have 
just after
a <command>REINDEX</command>.

-- 
Benoit Lobréau
Consultant
http://dalibo.com