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Re: Patch for circular buffer in tuplestore to optimize merge joins (v1)

From: Bruce Momjian <bruce(at)momjian(dot)us>
To: stark <stark(at)enterprisedb(dot)com>
Cc: pgsql-patches <pgsql-patches(at)postgresql(dot)org>
Subject: Re: Patch for circular buffer in tuplestore to optimize merge joins (v1)
Date: 2007-03-29 22:50:30
Message-ID: (view raw or whole thread)
Lists: pgsql-patches
Via IM, author says it is ready.

Your patch has been added to the PostgreSQL unapplied patches list at:

It will be applied as soon as one of the PostgreSQL committers reviews
and approves it.


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 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. 

[ Attachment, skipping... ]

> -- 
>   Gregory Stark
>   EnterpriseDB
> ---------------------------(end of broadcast)---------------------------
> TIP 6: explain analyze is your friend

  Bruce Momjian  <bruce(at)momjian(dot)us>

  + If your life is a hard drive, Christ can be your backup. +

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