On Sat, Nov 30, 2019 at 7:18 PM Sergei Kornilov <sk@zsrv.org> wrote:
Hello
Its possible to change order of index processing by parallel leader? In v35 patchset I see following order: - start parallel processes - leader and parallel workers processed index lixt and possible skip some entries - after that parallel leader recheck index list and process the skipped indexes - WaitForParallelWorkersToFinish
I think it would be better to: - start parallel processes - parallel leader goes through index list and process only indexes which are skip_parallel_index_vacuum = true - parallel workers processes indexes with skip_parallel_index_vacuum = false - parallel leader start participate with remainings parallel-safe index processing - WaitForParallelWorkersToFinish
This would be less running time and better load balance across leader and workers in case of few non-parallel and few parallel indexes.
Why do you think so? I think the advantage of the current approach is that once the parallel workers are launched, the leader can process indexes that don't support parallelism. So, both type of indexes can be processed at the same time.