cache lookups

To load the cache in several cases, we have to do it with sequential
scans, because there is no index on these tables, partially because they
didn't have multi-key indexes in the old days. I want to add system
indexes and have the cache use them before we go beta. I should finish
by the end of the weekend.

-- 
  Bruce Momjian                        |  http://www.op.net/~candle
  maillist@candle.pha.pa.us            |  (610) 853-3000
  +  If your life is a hard drive,     |  830 Blythe Avenue
  +  Christ can be your backup.        |  Drexel Hill, Pennsylvania 19026