Thanks for raising this idea! I am generally -1 on the idea of autovacuum performing parallel index vacuum, because I always felt that the parallel option should be employed in a targeted manner for a specific table. if you have a bunch of large tables, some more important than others, a/c may end up using parallel resources on the least important tables and you will have to adjust a/v settings per table, etc to get the right table to be parallel index vacuumed by a/v.
Also, with the TIDStore improvements for index cleanup, and the practical elimination of multi-pass index vacuums, I see this being even less convincing as something to add to a/v. Now, If I am going to allocate extra workers to run vacuum in parallel, why not just provide more autovacuum workers instead so I can get more tables vacuumed within a span of time? > Once we have parallel heap vacuum, as discussed in thread[1], it would > also likely be beneficial to incorporate it into autovacuum during > aggressive vacuum or failsafe mode. IIRC, index cleanup is disabled by failsafe. -- Sami Imseih Amazon Web Services (AWS)
