On Tue, Feb 18, 2025 at 4:43 PM Melanie Plageman <melanieplage...@gmail.com> wrote: > > 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.
I've attached the updated patches. In this version, I focused on parallelizing only the second pass over the heap. It's more straightforward than supporting the first pass, it still requires many preliminary changes though. Regards, -- Masahiko Sawada Amazon Web Services: https://aws.amazon.com
v9-0003-radixtree.h-support-shared-iteration.patch
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v9-0002-vacuumparallel.c-Support-parallel-table-vacuuming.patch
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v9-0004-tidstore.c-support-shared-iteration-on-TidStore.patch
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v9-0005-Move-some-fields-of-LVRelState-to-LVVacCounters-s.patch
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v9-0006-Support-parallelism-for-removing-dead-items-durin.patch
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v9-0001-Introduces-table-AM-APIs-for-parallel-table-vacuu.patch
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