On Mon, Feb 17, 2025 at 1:11 PM Masahiko Sawada <sawada.m...@gmail.com> wrote: > > On Fri, Feb 14, 2025 at 2:21 PM Melanie Plageman > <melanieplage...@gmail.com> wrote: > > > > Since the failure rate is defined as a percent, couldn't we just have > > parallel workers set eager_scan_remaining_fails when they get their > > chunk assignment (as a percentage of their chunk size)? (I haven't > > looked at the code, so maybe this doesn't make sense). > > IIUC since the chunk size eventually becomes 1, we cannot simply just > have parallel workers set the failure rate to its assigned chunk.
Yep. The ranges are too big (1-8192). The behavior would be too different from serial. > > Also, if you start with only doing parallelism for the third phase of > > heap vacuuming (second pass over the heap), this wouldn't be a problem > > because eager scanning only impacts the first phase. > > Right. I'm inclined to support only the second heap pass as the first > step. If we support parallelism only for the second pass, it cannot > help speed up freezing the entire table in emergency situations, but > it would be beneficial for cases where a big table have a large amount > of spread garbage. > > At least, I'm going to reorganize the patch set to support parallelism > for the second pass first and then the first heap pass. Makes sense. - Melanie
