Re: Add parameter jit_warn_above_fraction

Hi,

On Fri, Feb 25, 2022 at 04:16:01PM +0100, Magnus Hagander wrote:
> This patch adds a configuration parameter jit_warn_above_fraction that
> will cause a warning to be logged if the fraction of time spent on
> doing JIT is bigger than the specified one. For example, this can be
> used to track down those cases where JIT ends up taking 90% of the
> query runtime because of bad estimates...

I think that's tremendously useful, huge +1.

Just a few minor nit:

+ A value of 0 (the default)disables the warning.

missing space

+ ereport(WARNING,
+ (errmsg("JIT time was %ld ms of %d ms",
+ jit_time, msecs)));

"JIT time" may a bit obscure for users, how about "JIT total processing time"?"

+ gettext_noop("Sets the fraction of query time spent on JIT before writing"
+ "a warning to the log."),
+ gettext_noop("Write a message tot he server log if more than this"
+ "fraction of the query runtime is spent on JIT."
+ "Zero turns off the warning.")

missing spaces in the concatenated strings.

The rest of the patch looks good to me.