Re: Skip vacuum log report code in lazy_scan_heap() if possible

On 10/29/21, 3:54 AM, "Greg Nancarrow" <gregn4422(at)gmail(dot)com> wrote:
> When recently debugging a vacuum-related issue, I noticed that there
> is some log-report processing/formatting code at the end of
> lazy_scan_heap() that, unless the vacuum VERBOSE option is specified,
> typically results in no log output (as the log-level is then DEBUG2).
> I think it is worth skipping this code if ultimately nothing is going
> to be logged (and I found that even for a tiny database, a VACUUM may
> execute this code hundreds of times).
> I have attached a simple patch for this.

I think this logging only happens once per table, so I'm not sure it's
really worth it to short-circuit here. If it was per-page, IMO there
would be a much stronger case for it. That being said, I don't think
the proposed patch would hurt anything.

Nathan