Re: tid_blockno() and tid_offset() accessor functions

Masahiko Sawada <sawada.mshk@gmail.com>

From: Masahiko Sawada <sawada.mshk@gmail.com>
To: Ayush Tiwari <ayushtiwari.slg01@gmail.com>
Cc: pgsql-hackers@postgresql.org
Date: 2026-03-11T21:48:08Z
Lists: pgsql-hackers
On Fri, Feb 27, 2026 at 10:59 AM Ayush Tiwari
<ayushtiwari.slg01@gmail.com> wrote:
>
> Hi hackers,
>
> As of now we don't have any built-in way to extract the block and offset components from a TID. When people need to group by page (like for bloat analysis) or filter by specific blocks, they usually end up using the `ctid::text::point` hack:
>
>     SELECT (ctid::text::point)[0]::bigint AS blockno,
>            (ctid::text::point)[1]::int    AS offset
>     FROM my_table;
>
> This works, but it's pretty clunky, relies on the text representation, and isn't great if you're trying to parse TIDs outside of SQL.
>
> The attached patch adds two simple accessor functions:
> - `tid_blockno(tid) -> bigint`
> - `tid_offset(tid) -> integer`

How about adding the subscripting support for tid data type? For
example, ctid[0] returns bigint and ctid[1] returns int.

Regards,

-- 
Masahiko Sawada
Amazon Web Services: https://aws.amazon.com



Commits

  1. Add tid_block() and tid_offset() accessor functions