Re: Getting all entries in a single block with ctid

On Mon, Jan 16, 2012 at 4:08 PM, Tomas Vondra <tv(at)fuzzy(dot)cz> wrote:

> The only other solution is to check all possible items on the page. There
> may be up to 291 items (although it depends on block size and
> architecture, see MaxHeapTuplesPerPage in access/htup.h).
>
> Nice to know.

> Something like this should work
>
> ctid = '(123,0)'::tid OR ctid = '(123,1)'::tid OR ctid = '(123,2)'::tid
> OR ... OR ctid = '(123,290)'::tid
>

Yeah, that works, but it's kinda impractical... I'm mostly trying to figure
out how fragmented a table is,
by checking how must the blocks are shared - so that the worst one can be
scheduled for clustering...

> But maybe someone will recommend a better solution.
>

Hopefully - thanks anyway :)

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