Hi, Alexander! On Tue, 22 Oct 2024 at 11:34, Alexander Korotkov <aekorot...@gmail.com> wrote:
> On Mon, Oct 21, 2024 at 2:30 PM Alexander Korotkov <aekorot...@gmail.com> > wrote: > > > > On Mon, Oct 21, 2024 at 1:16 PM Dagfinn Ilmari Mannsåker > > <ilm...@ilmari.org> wrote: > > > Alexander Korotkov <aekorot...@gmail.com> writes: > > > > > > > On Mon, Oct 21, 2024 at 8:40 AM Andrei Lepikhov <lepi...@gmail.com> > wrote: > > > >> > > > >> On 21/10/2024 06:32, Dagfinn Ilmari Mannsåker wrote: > > > >> > Alexander Korotkov <aekorot...@gmail.com> writes: > > > >> > > > > >> >> +static Oid *in_progress_list; > > > >> >> +static int in_progress_list_len; > > > >> >> +static int in_progress_list_maxlen; > > > >> > > > > >> > Is there any particular reason not to use pg_list.h for this? > > > >> Sure. The type cache lookup has to be as much optimal as possible. > > > >> Using an array and relating sequential access to it, we avoid memory > > > >> allocations and deallocations 99.9% of the time. Also, quick access > to > > > >> the single element (which we will have in real life almost all of > the > > > >> time) is much faster than employing list machinery. > > > > > > Lists are actually dynamically resized arrays these days (see commit > > > 1cff1b95ab6ddae32faa3efe0d95a820dbfdc164), not linked lists, so > > > accessing arbitrary elements is O(1), not O(n). Just like this patch, > > > the size is doubled (starting at 16) whenever array is full. > > > > > > > +1, > > > > List with zero elements has to be NIL. That means continuous > > > > allocations/deallocations. > > > > > > This however is a valid point (unless we keep a dummy zeroth element to > > > avoid it, which is even uglier than open-coding the array extension > > > logic), so objection withdrawn. > > > > OK, thank you! > > > > The attached revision fixes EXTRA_INSTALL in > > src/test/modules/typcache/Makefile. Spotted off-list by Arthur > > Zakirov. > > I've re-checked that regression tests pass with > -DCLOBBER_CACHE_ALWAYS. Also did some grammar corrections for > comments and commit message. I'm going to push this if no objections. > Thank you for working on this patch! Looked through the patchset once more. Patch 0001 (minor): "in the last" -> "after everything else" or "after other TypeCacheEntry contents" Patch 0002 looks ready to me. Regards, Pavel Borisov Supabase
