Well, my plans for 6.4:
1. Btree: use TID as (last) part of index key; prepare btree
for low-level locking (it's now possible to lose root page).
2. Vacuum: speed up index cleaning; release pg_class lock after
updation statistic for a table.
3. Buffer manager: error handling broken; should flush only
buffers changed by backend itself.
4. Implement shared catalog cache; get rid of invalidation code.
5. Subselects: in target list; in FROM.
6. Transaction manager: get rid of pg_variable; do not prefetch
XIDs; nested transactions; savepoints.
Vadim
