Re: ctid & updates

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От Jan Wieck
Тема Re: ctid & updates
Дата
Msg-id 200206032000.g53K0mh03880@saturn.janwieck.net
обсуждение исходный текст
Ответ на ctid & updates  ("Joshua b. Jore" <josh@greentechnologist.org>)
Ответы Re: ctid & updates  ("Joshua b. Jore" <josh@greentechnologist.org>)
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Joshua b. Jore wrote:
> 1#
> I saw a post from Jan Wieck about how ctid can be used for a fast update.
> I noticed that ctid changes on update (as expected since it's really a new
> row). Is there anyway to get the new ctid from the update so later
> updates to the row can continue to use ctid to zero in on the row
> location?

    That's  one  of  the details I'm still thinking about. And in
    the case of a cursor using a junk attribute  it  gets  worse,
    because there is no easy way to push that new value back into
    the cursor's result set.

    But I doubt that this would become a real world problem ever.
    People  who  need to update one and the same DB row again and
    again during the same transaction are  spaghetti-code-script-
    kiddies  who know for sure that "a cursor's that thingy on ya
    screen that ya move withe mouse", so we're pretty  safe  here
    :-p

> 2#
> Also, is ctid unique for each row?

    Yes, per table.


Jan

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