Re: sqlsmith crash incremental sort
| От | Tom Lane |
|---|---|
| Тема | Re: sqlsmith crash incremental sort |
| Дата | |
| Msg-id | 20403.1587086800@sss.pgh.pa.us обсуждение исходный текст |
| Ответ на | Re: sqlsmith crash incremental sort (Tomas Vondra <tomas.vondra@2ndquadrant.com>) |
| Ответы |
Re: sqlsmith crash incremental sort
|
| Список | pgsql-hackers |
Tomas Vondra <tomas.vondra@2ndquadrant.com> writes:
> I think we have essentially three options:
> 1) assuming there's just a single group
> 2) assuming each row is a separate group
> 3) something in between
> If (1) and (2) are worst/best-case scenarios, maybe we should pick
> something in between. We have DEFAULT_NUM_DISTINCT (200) which
> essentially says "we don't know what the number of groups is" so maybe
> we should use that.
I wouldn't recommend picking either the best or worst cases.
Possibly DEFAULT_NUM_DISTINCT is a sane choice, though it's fair to
wonder if it's quite applicable to the case where we already know
we've grouped by some columns.
regards, tom lane
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