Re: Optimize LISTEN/NOTIFY

On Wed, Oct 15, 2025, at 16:16, Tom Lane wrote:
> I think we can perhaps salvage the idea if we invent a separate
> "advisory" queue position field, which tells its backend "hey,
> you could skip as far as here if you want", but is not used for
> purposes of SLRU truncation. 

I want to experiment with this idea too.

I assume the separate "advisory" queue position field
would actually need to be two struct fields, since a queue position
consists of a page and an offset, right?

   typedef struct QueuePosition
   {
     int64        page;            /* SLRU page number */
     int            offset;            /* byte offset within page */
+    int64        advisoryPage;    /* suggested skip-ahead page */
+    int            advisoryOffset;    /* suggested skip-ahead offset */
   } QueuePosition;

Or would we want rather want a single "advisory" field that would also
be of type QueuePosition?

/Joel