On Fri, Jul 24, 2020 at 09:14:04PM +0200, Pavel Stehule wrote:
> pá 24. 7. 2020 v 16:38 odesílatel Christophe Pettus
> napsal:
> > Since we already special-case parent tables for partition sets, would a
> > storage parameter that lets you either tell the planner "no, really, zero
> > is reasonabl
> On Jul 24, 2020, at 14:09, Tom Lane wrote:
> Rather than adding another pg_class column, I'm tempted to say that
> vacuum/analyze should set relpages to a minimum of 1, even if the
> relation has zero pages.
If there's not an issue about relpages != actual pages on disk, that certain
seems
Pavel Stehule writes:
> pá 24. 7. 2020 v 16:38 odesílatel Christophe Pettus
> napsal:
>> Since we already special-case parent tables for partition sets, would a
>> storage parameter that lets you either tell the planner "no, really, zero
>> is reasonable here" or sets a minimum number of rows to
> On Jul 24, 2020, at 12:14, Pavel Stehule wrote:
>
> this application stores some results in tables (as guard against repeated
> calculations). Lot of these tables have zero or one row.
Yes, that's the situation we encountered, too. It's not very common (and even
less common, I would assu
pá 24. 7. 2020 v 16:38 odesílatel Christophe Pettus
napsal:
>
>
> > On Jul 24, 2020, at 06:48, Tom Lane wrote:
> >
> > There's certainly not a lot besides tradition to justify the exact
> > numbers used in this case.
>
> Since we already special-case parent tables for partition sets, would a
> s
> On Jul 24, 2020, at 06:48, Tom Lane wrote:
>
> There's certainly not a lot besides tradition to justify the exact
> numbers used in this case.
Since we already special-case parent tables for partition sets, would a storage
parameter that lets you either tell the planner "no, really, zero
David Rowley writes:
> On Fri, 24 Jul 2020 at 16:01, Christophe Pettus wrote:
>> I realize I've never quite known this; where does the planner get the row
>> estimates for an empty table? Example:
> We just assume there are 10 pages if the relation has not yet been
> vacuumed or analyzed. The
On Fri, 24 Jul 2020 at 16:01, Christophe Pettus wrote:
> I realize I've never quite known this; where does the planner get the row
> estimates for an empty table? Example:
We just assume there are 10 pages if the relation has not yet been
vacuumed or analyzed. The row estimates you see are the
I realize I've never quite known this; where does the planner get the row
estimates for an empty table? Example:
psql (11.8)
Type "help" for help.
xof=# CREATE TABLE t (i integer, t text, j integer);
CREATE TABLE
xof=# VACUUM ANALYZE t;
VACUUM
xof=# EXPLAIN ANALYZE SELECT * FROM t;
