Query Performance after pg_restore

Hi,

I did pg_dump of a ~20TB database followed by pg_restore. I find simple queries like select count(*) running slow. I did a select count(*) on all tables before pg_dump which took ~4 hours. After pg_restore, same thing took 32 hours.

I ran “analyze verbose ;” on the database, but it did not help. It ran quick in 1.5 hours, but as you are aware it does sampling.

I am now running “vacuumdb -p <port-number> -a -z -j 10 -v”, but I do not know if it is going to help.

I am not sure if above vacuumdb helps, but if it helps what is it vacuuming in a pristine database? If it is doing some special “analyze”, what is it? Is there a way to run “full” analyze without sampling and without vacuuming?

By the way, there is no change in postgres versions. It is 14.4 before and after pg_restore.

Thanks!