Re: Ignore Some Updates

From: Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us>
To: cnliou(at)so-net(dot)net(dot)tw
Cc: "" <pgsql-performance(at)postgresql(dot)org>
Subject: Re: Ignore Some Updates
Date: 2004-01-13 04:59:35
Message-ID: 8021.1073969975@sss.pgh.pa.us
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"cnliou" <cnliou(at)so-net(dot)net(dot)tw> writes:
> I wonder it happens to systems where inefficient update
> SQL's are used like this:
> UPDATE MyTable SET MyColumn=1234
> Question arises when the value of MyColumn is already 1234
> before the update.

We have to fire UPDATE triggers in any case.

> If I am right, even when the to-be-updated column values
> equal to the new values, the core never hates to update that
> row anyway. If so, is it wise or not to adjust the core for
> lazy SQL users to ignore such "meaningless" updates in order

Seems like penalizing the intelligent people (by adding useless
comparisons) in order to reward the "lazy" ones.

regards, tom lane

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