> I hit an interestinhg paper on n_distinct calculation:
> the PCSA algorithm described there requires O(1) calculation per
> value. Page 22 describes what to do with updates streams.
> This I think (disclaimer: I know little about PG internals) means that
> the n_distinct estimation can be done during vacuum time (it would
> play well with the visibility map addon).
> What do You think?
ok, if You think that calculating a has function of every data field
for each insert or delete is prohibitive, just say so and don`t bother
reading the paper :]
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