On Sat, Jul 12, 2008 at 2:25 AM, Roberts, Jon <Jon.Roberts@xxxxxxxxxxx> wrote: >> >> -- > > I can find very little information on hot updates but I found this: http://archives.postgresql.org/pgsql-patches/2006-11/msg00059.php > > It states, "This design optimizies the updates when none of the index columns are modified and length of the tuple remains the same after update." > > How can a row's length change? I think it must mean the size (in bytes) of the row remains the same. > I bet you are looking at an old design. That has undergone many changes and the current implementation does not have any restriction about the row length changes. But a necessary condition is to have enough free space in the block (and of course not changing any index columns). You can find the latest README in the source code under src/backend/access/heap/README.HOT Thanks, Pavan -- Pavan Deolasee EnterpriseDB http://www.enterprisedb.com
