Re: Question regarding the database page layout.

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От Tom Lane
Тема Re: Question regarding the database page layout.
Дата
Msg-id 14022.1220368072@sss.pgh.pa.us
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Ответ на Re: Question regarding the database page layout.  ("Ryan Bradetich" <rbradetich@gmail.com>)
Ответы Re: Question regarding the database page layout.
Re: Question regarding the database page layout.
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"Ryan Bradetich" <rbradetich@gmail.com> writes:
> The patch concept is fairly simple.

>    1.  Add a new boolean local variable: require_max_align
> (initialized to false).

This really can't possibly work, because you'd need to propagate
knowledge of the tuple's alignment requirement all over the place.
In particular, how would code *reading* the tuple know where the
data starts?  Also, I don't think you get (very much of) the actual
benefit unless the code that inserts tuples into disk pages knows
to do something different in the int-align case.

It's conceivable that we could make this work if we wanted to dedicate
an infomask bit to showing whether the tuple needs int or double
alignment.  I don't really think it's worth the trouble though.
        regards, tom lane


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