2. For joining large tables (million's of rows) you don't
need an index on any column in the where clause.

Not true if low number of rows is gonna be returned, the poster in no where states that this is going to return many rows and your statement simply doesnt fit in general


3. Multi table query will join the tables first and then
filter the rows according to the where clause. You should
not be having an index lookup for the filter.

Here in no where you mentions about index, too general, does not apply to all cases, plus the poster says his indexes are being used by his predicates which means there are index and not as you said in your last post "Not having indexes on the columns in the where clause would have CBO do Full table scan". In his case his predicates are applied first for t1 then joined


As for original poster, you dont compare costs, that is used internally, not by you! And you should post the query plan for this kind of questions