What do you mean by 'three-part-naming issues'?
If the table resides in a separate db, then you reference the table you will need to include the db name, either in a synonym or view, or in the SELECT itself, like this:
SELECT
FROM dbo.table_in_db1
INNER JOIN db2.dbo.table_in_db2 ...
The log file will not be directly affected. Logging would be less overhead in a single db than if it had to go across 2 dbs, which causes a distributed transaction.
SQL DBA,SQL Server MVP(07, 08, 09) A socialist is someone who will give you the shirt off *someone else's* back.