Re: postgres_fdw: using TABLESAMPLE to collect remote sample
| От | Tom Lane |
|---|---|
| Тема | Re: postgres_fdw: using TABLESAMPLE to collect remote sample |
| Дата | |
| Msg-id | 951485.1672461744@sss.pgh.pa.us обсуждение исходный текст |
| Ответ на | Re: postgres_fdw: using TABLESAMPLE to collect remote sample (Tomas Vondra <tomas.vondra@enterprisedb.com>) |
| Ответы |
Re: postgres_fdw: using TABLESAMPLE to collect remote sample
|
| Список | pgsql-hackers |
Tomas Vondra <tomas.vondra@enterprisedb.com> writes:
> After thinking about it a bit more I decided to rip out the 10% sampling
> rate inflation.
+1. I'm not sure if there's anything more we need to do there, but
that didn't seem like that was it.
I notice that the committed patch still has a reference to that hack
though:
+ * Ensure the sampling rate is between 0.0 and 1.0, even after the
+ * 10% adjustment above. (Clamping to 0.0 is just paranoia.)
Clamping still seems like a wise idea, but the comment is just
confusing now.
Also, I wonder if there is any possibility of ANALYZE failing
with
ERROR: TABLESAMPLE clause can only be applied to tables and materialized views
I think the patch avoids that, but only accidentally, because
reltuples will be 0 or -1 for a view. Maybe it'd be a good
idea to pull back relkind along with reltuples, and check
that too?
regards, tom lane
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