On Tue, Aug 2, 2016 at 9:08 PM, Andreas Joseph Krogh <andr...@visena.com>
wrote:
> Hi.
>
> I see the RUM-index is updated, which is great!
>
> I wonder, to be able to sort by timestamp one has to create the index like
> this:
>
>
> CREATE INDEX rumidx ON origo_email_delivery USING rum (fts_all
> rum_tsvector_timestamp_ops, received_timestamp)
> WITH (attach = 'received_timestamp', TO = 'fts_all', order_by_attach =
> TRUE );
>
> Then, to be able to use the index for sorting by the
> "received_timestamp"-column one has to issue a query like this:
>
> EXPLAIN ANALYZE SELECT del.entity_id,
> del.subject,
> del.received_timestamp,
> fts_all <=> to_tsquery('simple', 'andreas&kr') AS rank
> FROM origo_email_delivery del
> WHERE del.fts_all @@ to_tsquery('simple', 'andreas&kr')
> ORDER BY '2000-01-01' :: TIMESTAMP <=> del.received_timestamp
> LIMIT 10;
>
> QUERY
> PLAN
> --------------------------------------------------------------------------------------------------------------------------------------------------
> Limit (cost=14.40..26.47 rows=10 width=89) (actual time=10.908..10.952
> rows=10 loops=1)
> -> Index Scan using rumidx on origo_email_delivery del
> (cost=14.40..3221.22 rows=2657 width=89) (actual time=10.906..10.947 rows=10
> loops=1)
> Index Cond: (fts_all @@ '''andreas'' & ''kr'''::tsquery)
> Order By: (received_timestamp <=> '2000-01-01 00:00:00'::timestamp
> without time zone)
> Planning time: 0.491 ms
> Execution time: 11.010 ms
> (6 rows)
>
>
> The ORDER BY part seems strange; It seems one has to find a value
> "lower than any other value" to use as a kind of base, why is this
> necessary? It also seems that in order to be able to sort DESC one has to
> provide a timestamp value "higher than any other value", is this correct?
>
have you considered <=| and |=> operators ? <=> in ORDER BY works like KNN.
>
> It would be great if the docs explained this.
>
> I really miss the opportunity to include a BIGINT as part of the index, so
> that the WHERE-clause could be like this:
>
> WHERE del.fts_all @@ to_tsquery('simple', 'andreas&kr') AND del.folder_id IN
> (1,2,3)
>
> Having this would be perfect for my use-case searching in email in
> folders, sorted by received_date, and having it use ONE index.
>
> Will this be supported?
>
> Thanks.
>
> --
> *Andreas Joseph Krogh*
> CTO / Partner - Visena AS
> Mobile: +47 909 56 963
> andr...@visena.com
> www.visena.com
> <https://www.visena.com>
>
