Message-Id: <6.2.1.2.0.20060429110036.02c01b98@localhost>
Date: Sat, 29 Apr 2006 11:18:10 +0800
To: Tom Lane <tgl@sss.pgh.pa.us>
From: K C Lau <kclau60@netvigator.com>
Subject: Re: Why so slow? 
Cc: pgsql-performance@postgresql.org
In-Reply-To: <19397.1146278368@sss.pgh.pa.us>
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At 10:39 06/04/29, Tom Lane wrote:
>K C Lau <kclau60@netvigator.com> writes:
> > Without knowing the internals, I have this simplistic idea: if Postgres
> > maintains the current lowest transaction ID for all active 
> transactions, it
> > probably could recycle dead tuples on the fly.
>
>[ yawn... ]  Yes, we've heard that before.  The hard part is getting rid
>of index entries.
>
>                         regards, tom lane

I apologize for simplistic ideas again. I presume that the equivalent tuple 
header information is not maintained for index entries. What if they are, 
probably only for the most commonly used index types to allow recycling 
where possible? The extra space required would be recycled too. It would 
probably also help save a trip to the tuple data pages to determine the 
validity of index entries during index scans.

Cheers,
KC.