On Sun, Feb 24, 2019 at 10:02 AM Gunther <raj@xxxxxxxx> wrote: > David Rowley and Justin Pryzby suggested things about autovacuum. But I don't think autovacuum has any helpful role here. My suspicion is that this has something to do with the behavior of B-Tree indexes with lots of duplicates. See also: https://www.postgresql.org/message-id/flat/CAH2-Wznf1uVBguutwrvR%2B6NcXTKYhagvNOY3-dg9dzcYiu_vKw%40mail.gmail.com#993f152a41a1e2c257d12d118aa7ebfc I am working on a patch to address the problem which is slated for Postgres 12. I give an illustrative example of one of the problems that my patch addresses here (it actually addresses a number of distinct issues all at once): https://postgr.es/m/CAH2-Wzmf0fvVhU+SSZpGW4Qe9t--j_DmXdX3it5JcdB8FF2EsA@xxxxxxxxxxxxxx Do you think that that could be a significant factor here? I found your response to my initial questions unclear. Using a Postgres table as a queue is known to create particular problems with bloat, especially index bloat. Fixing the underlying behavior in the nbtree code would likely sharply limit the growth in index bloat over time, though it still may not make queue-like tables completely painless to operate. The problem is described in high level terms from a user's perspective here: https://brandur.org/postgres-queues -- Peter Geoghegan
