Thanks you guys are correct... the size of the table caused the optimizer
to do a seq scan instead of using the index. I tried it on a 24 MB and 1
GB table and the expected index was used.
On Fri, Feb 17, 2017 at 7:04 PM, Tom Lane wrote:
> "David G. Johnston" writes:
> > On Fri, Feb 17, 2017
"David G. Johnston" writes:
> On Fri, Feb 17, 2017 at 3:49 PM, Tomas Vondra
> wrote:
>> That may seem a bit strange, but I'd bet it finds the short value in some
>> statistic (MCV, histogram) ans so can provide very accurate estimate.
> I'm not seeing how any of the statistic columns would capt
On Fri, Feb 17, 2017 at 3:49 PM, Tomas Vondra
wrote:
> That may seem a bit strange, but I'd bet it finds the short value in some
> statistic (MCV, histogram) ans so can provide very accurate estimate.
-> Index Only Scan using tab_idx1 on tab (cost=0.27..8.29 rows=1
width=0) (actual time=0
Yes, both queries are the same, I just shorten the parameter value to see
what would have happened. The database that I inherited has a column that
stores GUID/UUIDs in a varchar(255) and a select on that table on that
column is doing a FULL TABLE SCAN (seq scan). All the values in the column
are 3
On 02/17/2017 11:42 PM, David G. Johnston wrote:
On Fri, Feb 17, 2017 at 3:19 PM, Hustler DBA mailto:hustler...@gmail.com>>wrote:
my_db=# create index tab_idx1 on tab(ID);
CREATE INDEX
my_db=# explain (analyze, buffers) select count(*) from tab where ID
= '01625cfa-2bf8-45cf' ;
Hustler DBA wrote:
> I am seeing this strange behavior, I don't know if this is by design by
> Postgres.
>
> I have an index on a column which is defined as "character varying(255)".
> When the value I am searching for is of a certain length, the optimizer
> uses the index but when the value is lo
Hi,
On 02/17/2017 11:19 PM, Hustler DBA wrote:
I am seeing this strange behavior, I don't know if this is by design by
Postgres.
I have an index on a column which is defined as "character
varying(255)". When the value I am searching for is of a certain length,
the optimizer uses the index but w
On Fri, Feb 17, 2017 at 3:19 PM, Hustler DBA wrote:
>
> my_db=# create index tab_idx1 on tab(ID);
>
> CREATE INDEX
> my_db=# explain (analyze, buffers) select count(*) from tab where ID = '
> 01625cfa-2bf8-45cf' ;
> QUERY PLAN
>
>
