Re: pg_stat_io_histogram

Hi,

On 2026-03-17 13:13:59 +0100, Jakub Wartak wrote:
> 1. Concerns about memory use. With v7 I had couple of ideas, and with those
> the memory use is really minimized as long as the code is still simple
> (so nothing fancy, just some ideas to trim stuff and dynamically allocate
> memory). I hope those reduce memory footprint to acceptable levels, see my
> earlier description for v7.

Personally I unfortunately continue to think that storing lots of values that
are never anything but zero isn't a good idea once you have more than a
handful of kB. Storing pointless data is something different than increasing
memory usage with actual information.

I still think you should just count the number of histograms needed, have an
array [object][context][op] with the associated histogram "offset" and then
increment the associated offset. It'll add an indirection at count time, but
no additional branches.

Greetings,

Andres Freund