> > My wild guess is that deleting all index pointers for a removed
index
> > is more-or-less the same cost as creating new ones for
> > inserted/updated page.
>
> Only if you are willing to make the removal process
> recalculate the index keys from looking at the deleted tuple.

The bgwriter could "update" all columns of dead heap tuples in heap
pages
to NULL and thus also gain free space without the need to touch the
indexes.
The slot would stay used but it would need less space.

Andreas

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"Zeugswetter Andreas DAZ SD" <ZeugswetterA@spardat.at> writes:
> The bgwriter could "update" all columns of dead heap tuples in heap
> pages
> to NULL and thus also gain free space without the need to touch the
> indexes.
> The slot would stay used but it would need less space.

Not unless it's running a transaction (consider TOAST updates).

regards, tom lane

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