Including Snapshot Info with Indexes

Hi,<br />    Currently The index implementation in Postgresql does not store the  Snapshot information in the Index. If
weadd the snapshot information into the indexing structure, we will have the following advantages.<br /><br /> a) There
canbe index only scans like Oracle<br />b) Unique indexes will become less costly, as older index tuples can be found
out.<br/>c) Even the index scans will get faster, since some of the index tuples won't translate into HeapScans. <br
/>d)Deletes and Updates will become slightly costly, as they have to update these indexes.<br /><br />I propose we add
aDDL like "Create Index .. With Snapshot", which will have different relkind.<br /><br />The design in my mind is to
addthe Snapshot info together with the values as first variables. We need to change the Index_getattr slightly to have
therelkind as input parameter, based on which we can have an offset. <br /><br />Please reply back with your
comments.<br/><br />Thanks,<br />Gokul.<br />