Simon Riggs wrote: > I'm working on modifying Tuplestore that will allow you to store the > last N tuples, rather than all previous input. This is specifically > designed to allow Merge Join to do Mark/Restore without materializing > the whole sort set. This can also be used to materialize Windows (i.e. > <window clause> in SQL:2003), so you can store the current row plus n > PRECEDING and/or n FOLLOWING rows as appropriate.
Interesting. This could also be used to implement the "partial sort" stuff that Oleg is so interested in, and in which I believe Greg Stark was also interested. -- Alvaro Herrera http://www.CommandPrompt.com/ PostgreSQL Replication, Consulting, Custom Development, 24x7 support ---------------------------(end of broadcast)--------------------------- TIP 4: Have you searched our list archives? http://archives.postgresql.org
