Re: Updated RUM-index and support for bigint as part of index

From: Artur Zakirov <a(dot)zakirov(at)postgrespro(dot)ru>
To: Andreas Joseph Krogh <andreas(at)visena(dot)com>, pgsql-general(at)postgresql(dot)org
Cc: Oleg Bartunov <obartunov(at)gmail(dot)com>
Subject: Re: Updated RUM-index and support for bigint as part of index
Date: 2016-08-11 17:13:10
Message-ID: 0c49e73e-0b33-c981-210e-8da136a7ff9c@postgrespro.ru
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On 07.08.2016 11:05, Andreas Joseph Krogh wrote:
> På søndag 07. august 2016 kl. 08:27:06, skrev Oleg Bartunov
> <obartunov(at)gmail(dot)com <mailto:obartunov(at)gmail(dot)com>>:
>
> [snip]
> have you considered <=| and |=> operators ? <=> in ORDER BY works
> like KNN.
>
>
> I don't get how these operators should work. Neither give me the
> expected results.
>
> Using <=>
>
>
> SELECT del.entity_id, del.folder_id, del.received_timestamp FROM
> origo_email_delivery del WHERE del.fts_all @@ to_tsquery('simple',
> 'andreas:*&jose:*') ORDER BY '2000-01-01' :: TIMESTAMP <=>
> del.received_timestamp LIMIT 10;
>
> entity_id | folder_id | received_timestamp
> -----------+-----------+-------------------------
> 1224278 | 1068087 | 2015-08-17 23:53:26
> 1224382 | 1068087 | 2015-08-18 03:07:55
> 1224404 | 1068087 | 2015-08-18 03:49:02
> 1505713 | 48496 | 2015-10-27 14:51:45
> 142132 | 66658 | 2012-12-03 14:14:05.488
> 122565 | 90115 | 2012-11-20 15:41:04.936
> 200744 | 66655 | 2013-01-28 21:47:44.561
> 1445927 | 888665 | 2015-09-29 00:26:56
> 123671 | 83509 | 2012-11-21 14:16:26.448
> 1129928 | 66658 | 2015-05-09 08:39:14.128
> (10 rows)
>
>
> Using <=|
>
> SELECT del.entity_id, del.folder_id, del.received_timestamp FROM
> origo_email_delivery del WHERE del.fts_all @@ to_tsquery('simple',
> 'andreas:*&jose:*') ORDER BY '2000-01-01' :: TIMESTAMP <=|
> del.received_timestamp LIMIT 10;
>
>
> entity_id | folder_id | received_timestamp
> -----------+-----------+-------------------------
> 1224278 | 1068087 | 2015-08-17 23:53:26
> 1224382 | 1068087 | 2015-08-18 03:07:55
> 1224404 | 1068087 | 2015-08-18 03:49:02
> 1505713 | 48496 | 2015-10-27 14:51:45
> 142132 | 66658 | 2012-12-03 14:14:05.488
> 122565 | 90115 | 2012-11-20 15:41:04.936
> 200744 | 66655 | 2013-01-28 21:47:44.561
> 1445927 | 888665 | 2015-09-29 00:26:56
> 123671 | 83509 | 2012-11-21 14:16:26.448
> 1129928 | 66658 | 2015-05-09 08:39:14.128
> (10 rows)
>
>
> Neither are ordered by received_timestamp
>
> Can you explain how to get ORDER BY received_timestamp DESC?
>
> Thanks.
>
> --
> *Andreas Joseph Krogh*
> CTO / Partner - Visena AS
> Mobile: +47 909 56 963
> andreas(at)visena(dot)com <mailto:andreas(at)visena(dot)com>
> www.visena.com <https://www.visena.com>
> <https://www.visena.com>
>

Do you need simple ordering by received_timestamp column? Not ordering
by distance between received_timestamp and some date?

Then you can use simple "ORDER BY received_timestamp". For example, we
have data:

=# SELECT * FROM test;
id | fts | received
----+-------------+-------------------------
1 | 'andreas':1 | 2015-08-17 23:53:26
2 | 'andreas':1 | 2015-08-18 03:07:55
3 | 'andreas':1 | 2015-08-18 03:49:02
4 | 'andreas':1 | 2012-12-03 14:14:05.488
5 | 'andreas':1 | 2012-11-20 15:41:04.936
6 | 'andreas':1 | 2013-01-28 21:47:44.561
6 | 'andreas':1 | 2015-09-29 00:26:56
7 | 'andreas':1 | 2012-11-21 14:16:26.448
8 | 'andreas':1 | 2015-05-09 08:39:14.128
(9 rows)

I created index:

CREATE INDEX rumidx ON test USING rum (fts rum_tsvector_timestamp_ops,
received) WITH (attach = 'received', to = 'fts');

Then we can execute queries:

=# SELECT id, received FROM test WHERE fts @@ to_tsquery('simple',
'andreas') ORDER BY received LIMIT 8;
id | received
----+-------------------------
5 | 2012-11-20 15:41:04.936
7 | 2012-11-21 14:16:26.448
4 | 2012-12-03 14:14:05.488
6 | 2013-01-28 21:47:44.561
8 | 2015-05-09 08:39:14.128
1 | 2015-08-17 23:53:26
2 | 2015-08-18 03:07:55
3 | 2015-08-18 03:49:02
(8 rows)

=# SELECT id, received FROM test WHERE fts @@ to_tsquery('simple',
'andreas') ORDER BY received DESC LIMIT 8;
id | received
----+-------------------------
6 | 2015-09-29 00:26:56
3 | 2015-08-18 03:49:02
2 | 2015-08-18 03:07:55
1 | 2015-08-17 23:53:26
8 | 2015-05-09 08:39:14.128
6 | 2013-01-28 21:47:44.561
4 | 2012-12-03 14:14:05.488
7 | 2012-11-21 14:16:26.448
(8 rows)

Operators <=>, |=>, <=| you can use to order by nearest date to specific
date:

=# SELECT id, received, received <=> '2013-01-01' AS rank FROM test
WHERE fts @@ to_tsquery('simple', 'andreas') ORDER BY received <=>
'2013-01-01' LIMIT 8;
id | received | rank
----+-------------------------+--------------
6 | 2013-01-28 21:47:44.561 | 2411264.561
4 | 2012-12-03 14:14:05.488 | 2454354.512
7 | 2012-11-21 14:16:26.448 | 3491013.552
5 | 2012-11-20 15:41:04.936 | 3572335.064
8 | 2015-05-09 08:39:14.128 | 74162354.128
1 | 2015-08-17 23:53:26 | 82857206
2 | 2015-08-18 03:07:55 | 82868875
3 | 2015-08-18 03:49:02 | 82871342
(8 rows)

=# SELECT id, received, received <=> '2013-01-01' AS rank FROM test
WHERE fts @@ to_tsquery('simple', 'andreas') ORDER BY received <=>
'2013-01-01' DESC LIMIT 8;
id | received | rank
----+-------------------------+--------------
6 | 2015-09-29 00:26:56 | 86488016
3 | 2015-08-18 03:49:02 | 82871342
2 | 2015-08-18 03:07:55 | 82868875
1 | 2015-08-17 23:53:26 | 82857206
8 | 2015-05-09 08:39:14.128 | 74162354.128
5 | 2012-11-20 15:41:04.936 | 3572335.064
7 | 2012-11-21 14:16:26.448 | 3491013.552
4 | 2012-12-03 14:14:05.488 | 2454354.512
(8 rows)

I hope this is what you want.

--
Artur Zakirov
Postgres Professional: http://www.postgrespro.com
Russian Postgres Company

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