Re: [GENERAL] Question slow query

2017-01-12 16:48 GMT+13:00 Andreas Joseph Krogh <andreas@visena.com>:

På torsdag 12. januar 2017 kl. 03:15:59, skrev Patrick B <patrickbakerbr@gmail.com>:

Hi guys,

 

I've got a slow query, running at 25 seconds.

 

                          ->  Bitmap Heap Scan on ja_notes r_1103088  (cost=234300.55..1254978.62 rows=553275 width=101) (actual time=1423.411..10572.549 rows=475646 loops=1)                               Recheck Cond: (n_type = ANY ('{note,note_1,note_2}'::n_type[]))                               Filter: (timezone('Etc/UTC'::text, d_modified) >= '2016-08-07 23:12:34'::timestamp without time zone)                               Rows Removed by Filter: 13725231

 

 

As you can see, 13.725.231 rows were removed by Filter..

 

Should I create an index for this column?

d_modified              | timestamp with time zone | default statement_timestamp()

I tried but it didn't help... the query doesn't even hit the index.

 

CREATE INDEX q ON test USING BTREE (d_modified);

 

Am I missing something? 

 

Yes, you've not shown us:

1. The query

2. The schema

3. Complete EXPLAIN-output

 

Sorry about that.. just wanted to understand how to index a timestamp column. I was able to do this way:

CREATE INDEX CONCURRENTLY ON note (timezone('Etc/UTC'::text, d_date));