On 12.03.26 17:51, Masahiko Sawada wrote:
On Wed, Mar 11, 2026 at 2:50 PM Andres Freund <[email protected]> wrote:
Hi,
On 2026-03-11 14:48:08 -0700, Masahiko Sawada wrote:
On Fri, Feb 27, 2026 at 10:59 AM Ayush Tiwari
<[email protected]> 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.
That just seems less readable and harder to find to me. I think it'd also
make the amount of required code noticeably larger?
Yeah, using the dedicated functions would be more intuitive than using
magic numbers 1 and 2, and require less code.
Also, you can use one-argument functions like field names, like
tid.tid_blockno, so it's definitely more intuitive that way.
