On Fri, Dec 8, 2023 at 11:24 PM Alexander Korotkov <aekorot...@gmail.com> wrote: > > Hi, Ashutosh! > > On Fri, Dec 8, 2023 at 3:28 PM Ashutosh Bapat > <ashutosh.bapat....@gmail.com> wrote: > > I did some analysis of memory consumption by bitmapsets in such cases. > > [1] contains slides with the result of this analysis. The slides are > > crude and quite WIP. But they will give some idea. > > > > [1] > > https://docs.google.com/presentation/d/1S9BiAADhX-Fv9tDbx5R5Izq4blAofhZMhHcO1c-wzfI/edit?usp=sharing > > Thank you for sharing your analysis. I understand that usage of a > plain bitmap becomes a problem with a large number of partitions. But > I wonder what does "post proposed fixes" mean? Is it the fixes posted > in [1]. If so it's very surprising for me they are reducing the > memory footprint size.
No. These are fixes in various threads all listed together in [1]. I had started investigating memory consumption by Bitmapsets around the same time. The slides are result of that investigation. I have updated slides with this reference. [1] https://www.postgresql.org/message-id/caexhw5s_kwb0rb9l3turjxsvo5uctepdskkaemb5x1etssm...@mail.gmail.com They reduce the memory footprint by Bitmapset because they reduce the objects that contain the bitmapsets, thus reducing the total number of bitmapsets produced. -- Best Wishes, Ashutosh Bapat
