Is there a performance gain in specifying the table name in joins and using explicit cast? Is there any performance gain by the interpreter of the query is I specify the table on a join and make the cast explicit?

Instead of

...
join table_join on field1_from = field1_join and field2_join = '2'
...


using

...
join table_join on table_from.field1_from = table_join.field1_join and table_join.field2_join::text = '2'::text
...


It seems that this should make the job of the parser a little easier
It is a good practice to use aliases to qualify tables etc

Select a.c1, b.c2
From table1 as a
 ....


However, that has very little to do with performance. Identifying each table etc is only a fraction of what the optimizer does and I would be surprised if it even is noticeable.