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.


This item was previously discussed here:

(this changes tuplestore.c not tuplesort.c, though its clear in the

> 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

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