(snip)Only 3 Tables hold the login info. Each Table has only 1 or 2 indexes. These are small Tables with a few rows being inserted / updated into each table per user login
Approx a Total of 30,000 Concurrent users will login to do a set of OLTP Transactions for an upcoming Benchmark.
Beware that each concurrent user will use an extent for each table and index in the temp tablespace, and that is a lot of space; assuming the popular 1M size for the extent size, that could be at least (3 tables + 3 indexes) * 30,000 user * 1M = 180 Gigabytes (!).
Plus, sure, a lot of almost-empty blocks (short rows) contending for space in the buffer cache.
Better use a permanent table in my opinion, maybe with a logoff trigger to clean up the rows when a gracefully-terminated session ends.
Or, sure, sys_context. -- Alberto Dell'Era "Per aspera ad astra" -- //www.freelists.org/webpage/oracle-l