On Thu, Mar 11, 2021 at 2:22 PM Peter Geoghegan <[email protected]> wrote: > It is convoluted. The issue that led to my backpatching to 13 was tied > to a 4% - 16% regression in an append-only workload by Mark Callaghan > (he is well known as the main person behind MyRocks at Facebook): > > https://smalldatum.blogspot.com/2021/01/insert-benchmark-postgres-is-still.html > > Autovacuums driven by autovacuum_vacuum_insert_threshold scan indexes > without receiving any benefit for it. Clearly > vacuum_cleanup_index_scale_factor was misdesigned, but that only > became a real problem with autovacuum_vacuum_insert_threshold. That > did not seem acceptable to me. It'll get worse and worse as you add > more and more indexes.
I can understand that those two settings might interact in some way that is bad or unintended, but I feel like if I can't understand what exactly the bad interaction is after reading the commit message, that's probably a sign that the commit message isn't as clear as it could be. -- Robert Haas EDB: http://www.enterprisedb.com
