Re: Adding skip scan (including MDAM style range skip scan) to nbtree - Mailing list pgsql-hackers

On Fri, May 9, 2025 at 8:58 AM Tomas Vondra <tomas@vondra.me> wrote:
> I'm also not sure about the root cause, but while investigating it one
> of the experiments I tried was tweaking the glibc malloc by setting
>
>     export MALLOC_TOP_PAD_=$((64*1024*1024))
>
> which keeps a 64MB "buffer" in glibc, to reduce the amount of malloc
> syscalls. And with that, the results change to this:

You're sure that the problem is an increase in the number of
malloc()s? If that's what this is, then it shouldn't be too hard to
debug.

--
Peter Geoghegan