On Tue, 2007-03-27 at 13:32 +0100, stark wrote: > This patch implements a circular buffer in tuplestore which drops old tuples > as they're no longer needed. It uses this for merge joins to avoid having to > spill the tuplestore if no single value exceeds work_mem. It also is what's > needed for both recursive query support and OLAP window functions (hence why > it implements the more complex circular buffer rather than just moving the > single tuple up to the head of the buffer). > > This was mostly already done by Simon, I just finished the logic in > tuplesort.c.
Cool. This item was previously discussed here: http://archives.postgresql.org/pgsql-hackers/2007-01/msg00096.php (this changes tuplestore.c not tuplesort.c, though its clear in the patch) > This is actually not quite polished so I guess it's still a WIP but it's > certainly ready to be reviewed. All that remains is polishing. If there's > anything in there people object to now I would like to know. I guess a performance test would be a great eyecatcher here, but it does seem otherwise complete. Any eager merge join testers out there? -- Simon Riggs EnterpriseDB http://www.enterprisedb.com ---------------------------(end of broadcast)--------------------------- TIP 3: Have you checked our extensive FAQ? http://www.postgresql.org/docs/faq
