|From:||"Hitoshi Harada" <umi(dot)tanuki(at)gmail(dot)com>|
|Subject:||Re: Window functions patch v04 for the September commit fest|
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2008/8/30 Hitoshi Harada <umi(dot)tanuki(at)gmail(dot)com>:
> Here's the latest window functions patch against HEAD. It seems to be
> ready for the September commit fest, as added documents, WINDOW clause
> feature and misc tests. I guess this would be the window functions
> feature freeze for 8.4. The remaining feature will be implemented for
> the later release.
> This patch consists of:
> - windowed aggregates
> - cooperate with GROUP BY aggregates
> - some optimizations with multiple windows
> - ranking functions
> - WINDOW clause
> - windowing SQL regression tests
> - sgml documents
> Looking up the total road map, the dropped features are:
> - sliding window (window framing)
> - lead(), lag(), etc. that reach for random rows
> - user defined window functions
> The first and second topics are difficult to implement currently.
> Because these features require random row access, it seems that
> tuplestore would be able to save multiple positions to mark/restore.
> This is fundamental change that is over my capability. Also, user
> defined window functions seem to have much more to decide. I think I
> can't put into shape the general needs of user's window functions now.
> Lacking these feature, this stage looks compatible to SQLServer 2005,
> while Oracle and DB2 have almost full of the specification.
> Also, current implementation has only a type of plan which uses sort
> operation. It should be optimized by re-position the windows and/or
> using hashtable.
> Oh, git hosting repository is updated as well.
README is updated.
Please add link to commit fest wiki.
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