Ühel kenal päeval, E, 2006-11-13 kell 13:42, kirjutas Csaba Nagy:
> [snip]
> > IMHO *most* UPDATEs occur on non-indexed fields. [snip]
> >
> > If my assumption is badly wrong on that then perhaps HOT would not be
> > useful after all. If we find that the majority of UPDATEs meet the HOT
> > pre-conditions, then I would continue to advocate it.
>
> Just to confirm that the scenario is valid: our application has almost
> all it's updates affecting only non-indexed columns. There are a few
> exceptions, but the vast majority is non-indexed, and that holds to the
> execution frequency too, not just for the count of tables/queries.
One interesting case which should also be considered is conditional
indexes:
create index on payments(payment_id) where status = 'waiting';
here the payment_id is not changed when processing the payment, but when
status is changed to 'processed' it still should be removed from the
index.
How would this interact with HOT ?
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