Re: Thoughts on maintaining 7.3

From: Rod Taylor <rbt(at)rbt(dot)ca>
To: Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us>
Cc: Alvaro Herrera <alvherre(at)dcc(dot)uchile(dot)cl>, "Joshua D(dot) Drake" <jd(at)commandprompt(dot)com>, PostgreSQL Development <pgsql-hackers(at)postgresql(dot)org>
Subject: Re: Thoughts on maintaining 7.3
Date: 2003-10-02 12:28:08
Message-ID: 1065060781.86529.8.camel@jester
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> For example, if you have a timestamp index and you routinely clean out
> all entries older than N-days-ago, you won't have a problem in 7.4.
> If your pattern is to delete nine out of every ten entries (maybe you
> drop minute-by-minute entries and keep only hourly entries after awhile)
> then you might find the index loading getting unpleasantly low. We'll
> have to see whether it's a problem in practice. I'm willing to revisit
> the page-merging problem if it's proven to be a real practical problem,
> but it looked hard enough that I think it's more profitable to spend the
> development effort elsewhere until it's proven necessary.

A pattern I have on a few tables is to record daily data. After a
period of time, create an entry for a week that is the sums of 7 days,
after another period of time compress 4 weeks into a month.

Index is on the date representing the block. It's a new insert, but
would go onto the old page. Anyway, I don't have that much data (~20M
rows) -- but I believe it is a real-world example of this pattern.

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