/9.0/static/row-estimation-examples.html
was a big help.
Matt
On Wed, Feb 27, 2013 at 9:08 AM, Matt Daw wrote:
> Quick follow up... I've found that the row estimate in:
>
> explain select count(id) from versions where project_id IN (80,115)
> A
ing the
same as (project_id=115) on its own.
Matt
On Tue, Feb 26, 2013 at 11:35 AM, Matt Daw wrote:
> Howdy, the query generator in my app sometimes creates redundant
> filters of the form:
>
> project_id IN ( ) AND
> project_id =
>
> ... and this is leading to a bad estimat
Howdy, the query generator in my app sometimes creates redundant
filters of the form:
project_id IN ( ) AND
project_id =
... and this is leading to a bad estimate (and thus a bad plan) on a
few complex queries. I've included simplified examples below. This
server is running 9.0.10 and the stati
((code)::text
~~* '%comp%'::text))
Rows Removed by Filter: 1
Total runtime: 147.411 ms
(14 rows)
On Fri, Sep 28, 2012 at 2:47 PM, Matt Daw wrote:
> Hi Tom, thank you very much. I'll load these tables onto a 9.2 instance
> and report back.
>
>
Hi Tom, thank you very much. I'll load these tables onto a 9.2 instance and
report back.
Matt
On Fri, Sep 28, 2012 at 2:44 PM, Tom Lane wrote:
> Matt Daw writes:
> > Howdy, I've been debugging a client's slow query today and I'm curious
> > about the q
Howdy, I've been debugging a client's slow query today and I'm curious
about the query plan. It's picking a plan that hashes lots of rows from the
versions table (on v9.0.10)...
EXPLAIN ANALYZE
SELECT COUNT(*) FROM notes a WHERE
a.project_id = 114 AND
EXISTS (
SELECT 1 FROM note_links b
WH
ost=0.00..94459.07 rows=1926207 width=0) (actual
time=0.005..1475.218 rows=1926207 loops=1)
Total runtime: 2889.360 ms
(3 rows)
Time: 2889.842 ms
On Tuesday, 21 August, 2012 at 3:57 PM, Matt Daw wrote:
> Howdy. I'm curious what besides raw hardware speed determines the performance
Howdy. I'm curious what besides raw hardware speed determines the performance
of a Seq Scan that comes entirely out of shared buffers… I ran the following on
the client's server I'm profiling, which is otherwise idle:
EXPLAIN (ANALYZE ON, BUFFERS ON) SELECT * FROM notes;
Seq Scan on notes (cos
