Hi, On 2023-06-26 13:40:49 -0400, James Coleman wrote: > Have we ever discussed running an analyze immediately after creating a table?
That doesn't make a whole lot of sense to me - we could just insert the constants stats we wanted in that case. > Consider the following: > > create table stats(i int, t text not null); > explain select * from stats; > Seq Scan on stats (cost=0.00..22.70 rows=1270 width=36 > analyze stats; > explain select * from stats; > Seq Scan on stats (cost=0.00..0.00 rows=1 width=36) > > Combined with rapidly increasing error margin on row estimates when > adding joins means that a query joining to a bunch of empty tables > when a database first starts up can result in some pretty wild plan > costs. The issue is that the table stats are likely going to quickly out of date in that case, even a hand full of inserts (which wouldn't trigger autovacuum analyzing) would lead to the "0 rows" stats causing very bad plans. Greetings, Andres Freund
