Querying a time range across multiple partitions
| От | Cal Heldenbrand |
|---|---|
| Тема | Querying a time range across multiple partitions |
| Дата | |
| Msg-id | CAAcwKheH7rCjdCbvyj-zEN=GZvrj2zGV9tywC-Q72BCA=T+CNA@mail.gmail.com обсуждение исходный текст |
| Ответы |
Re: Querying a time range across multiple partitions
(Alban Hertroys <haramrae@gmail.com>)
Re: Querying a time range across multiple partitions (John R Pierce <pierce@hogranch.com>) Re: Querying a time range across multiple partitions (David G Johnston <david.g.johnston@gmail.com>) Re: Querying a time range across multiple partitions (Jeff Janes <jeff.janes@gmail.com>) |
| Список | pgsql-general |
Hi everyone,
I'm trying to run a select query from a span of child partitions, separated out in daily tables, in Postgres 9.1.5. The parent looks like this:# \d logins
Table "public.logins"
Column | Type | Modifiers
-------------+-----------------------------+-----------
username | character varying(50) |
event | character varying(20) |
time | timestamp without time zone |
host | character varying(18) |
hash | character varying(32) |
Triggers:
logins_log_trigger BEFORE INSERT ON logins FOR EACH ROW EXECUTE PROCEDURE logins_insert_trigger()
Number of child tables: 1581 (Use \d+ to list them.)
# \d logins_20140904
Table "public.logins_20140904"
Column | Type | Modifiers
-------------+-----------------------------+-----------
username | character varying(50) |
event | character varying(20) |
time | timestamp without time zone |
host | character varying(18) |
hash | character varying(32) |
Indexes:
"logins_20140904_event" hash (event)
"logins_20140904_event_time" btree (event, "time")
"logins_20140904_username" hash (username)
"logins_20140904_username_time" btree (username, "time")
Check constraints:
"logins_20140904_time_check" CHECK ("time" >= '2014-09-04 00:00:00'::timestamp without time zone AND "time" <= '2014-09-04 23:59:59.99'::timestamp without time zone)
Inherits: logins
explain analyze select time,event from logins
where username='bob' and hash='1234' and time > current_date - interval '1 week';
Result (cost=0.00..765.11 rows=1582 width=14)
-> Append (cost=0.00..765.11 rows=1582 width=14)
-> Seq Scan on logins (cost=0.00..0.00 rows=1 width=66)
Filter: (((username)::text = 'bob'::text) AND ((hash)::text = '1234'::text) AND ("time" > (('now'::text)::date - '7 days'::interval)))
-> Index Scan using logins_20100501_username_time on logins_20100501 logins (cost=0.01..0.48 rows=1 width=14)
...
explain analyze select time,event from logins
where username='bob' and hash='1234' and time in ('2014-09-04', '2014-09-05', '2014-09-03');
Result (cost=0.00..2.41 rows=3 width=31) (actual time=0.060..0.060 rows=0 loops=1)
-> Append (cost=0.00..2.41 rows=3 width=31) (actual time=0.060..0.060 rows=0 loops=1)
-> Seq Scan on logins (cost=0.00..0.00 rows=1 width=66) (actual time=0.001..0.001 rows=0 loops=1)
Filter: (((username)::text = 'bob'::text) AND ((hash)::text = '1234'::text) AND ("time" = ANY ('{"2014-09-04 00:00:00","2014-09-05 00:00:00","2014-09-03 00:00:00"}'::timestamp without time zone[])))
-> Bitmap Heap Scan on logins_20140903 logins (cost=1.09..1.20 rows=1 width=14) (actual time=0.039..0.039 rows=0 loops=1)
...
So far, I've been messing around with generating a series, then collecting it back into an array, but nothing I've tried seems to work.
A few examples:
explain analyze select time,event from logins
where username='bob' and hash=1234' and time in (
generate_series(current_date - interval '3 days', current_date, interval '1 day')
);
ERROR: argument of IN must not return a set
explain analyze select time,event from logins
where username='bob' and hash='1234' and time in (
select array_agg(series)
from generate_series(current_date - interval '3 days', current_date, interval '1 day')
as u(series)
);
ERROR: operator does not exist: timestamp without time zone = timestamp without time zone[]
explain analyze select time,event from logins
where username='bob' and hash=1234 and time in (
select unnest(array_agg(date_trunc('day',series))) from
generate_series(current_date - interval '3 days', current_date, interval '1 day') as u(series)
)
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