On 21/12/2021 00:05, Peter Geoghegan wrote:
* Some index AMs don't work like nbtree and GiST in that they cannot do their scan sequentially -- they have to do something like a logical/keyspace order scan instead, which is *totally* different to heapam (not just a bit different). There is no telling how many times each page will be accessed in these other index AMs, and in what order, even under optimal conditions. We should arguably not even try to provide any granular progress information here, since it'll probably be too messy.
Maybe we could add callbacks into AM interface for send/receive/representation implementation of progress? So AM would define a set of parameters to send into stat collector and show to users.
-- regards, Andrey Lepikhov Postgres Professional