Christopher Kings-Lynne wrote: > > > Af far as I know Oracle doesn't have any short cut (along the lines of > > > what is being discussed in this thread) for this operation. However > > > Oracle is more efficient in providing the answer than postgres > > currently > > > is. While postgres needs to perform a full scan on the table, Oracle > > > will only need to perform a full index scan on the primary key if one > > > exists. Since the index will likely have much less data than the full > > > > Under Postgres, a full index scan is generally more expensive than a full > > table scan since indices, particularly btree, carry a large amount of meta > > data and theefore consume more pages. > > Don't forget that Postgres also doesn't store tids in the index, so must
I assume you mean xid here. tids are in the index or there would be no way to find the heap row. :-) > always check with the main table that a row is visible in current > transaction. -- Bruce Momjian | http://candle.pha.pa.us [EMAIL PROTECTED] | (610) 853-3000 + If your life is a hard drive, | 830 Blythe Avenue + Christ can be your backup. | Drexel Hill, Pennsylvania 19026 ---------------------------(end of broadcast)--------------------------- TIP 5: Have you checked our extensive FAQ? http://www.postgresql.org/users-lounge/docs/faq.html
