On Wed, Oct 30, 2024 at 10:35 AM Peter Geoghegan <pg@xxxxxxx> wrote:
On Wed, Oct 30, 2024 at 11:24 AM Don Seiler <don@xxxxxxxxx> wrote:
> One thing worth mentioning is that the table is 4 columns, the index is on two of them and includes the other two. I can't think of an explanation for the index being so much larger than its table, especially compared to last month's index.
>
> Curious if anyone has any thoughts on what might be causing this.
You mentioned that this has 4 columns. Sounds like this could be a
"locally monotonically increasing index". I wonder if you're
benefiting from this optimization, though only inconsistently:
https://www.youtube.com/watch?v=p5RaATILoiE&t=2079s
https://git.postgresql.org/gitweb/?p=postgresql.git;a=commit;h=f21668f3
Of course, this is only a guess. I vaguely recall a complaint that
sounded vaguely like yours, also involving partitioning.
Thanks Peter, I'll look into that shortly.
I should have also included that this is on PG 15 (currently 15.8 but we created the indexes when it was still 15.7) on Ubuntu 22.04 LTS.
Don.
Don Seiler
www.seiler.us
www.seiler.us
