locks within select - Mailing list pgsql-general

To my understanding, a select on a table does acquire an access share lock on that table.

my question is: is there any other kind of lock that a select may acquire ?

obviously, all explicit locking schemes like select for update, etc... is out of this question scope.

I was wondering if for example, within a join, some kind of lock may be acquired so that the dataset concerned is not changed during execution ? (for example a delete then autovacuum ??)

thanks