Re: Searching GIN-index (FTS) and sort by timestamp-column

På onsdag 16. mars 2016 kl. 14:53:04, skrev Andreas Joseph Krogh <
andreas(at)visena(dot)com <mailto:andreas(at)visena(dot)com>>:
På onsdag 16. mars 2016 kl. 14:37:27, skrev Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us
<mailto:tgl(at)sss(dot)pgh(dot)pa(dot)us>>:
Andreas Joseph Krogh <andreas(at)visena(dot)com> writes:
> 1. Why isnt' folder_id part of the index-cond?

Because a GIN index is useless for sorting.

> 2. Is there a way to make it use the (same) index to sort by
> received_timestamp?

No.

> 3. Using a GIN-index, is there a way to use the index at all for sorting?

No.

> 4. It doesn't seem like ts_rank uses the index for sorting either.

Same reason.

regards, tom lane
 
So it's basically impossible to use FTS/GIN with sorting on large datasets?
Are there any plans to improve this situation?
 
Thanks.
 
This paper talks about ORDER BY optimizations for FTS (starting at slide 6 and
7):
http://www.sai.msu.su/~megera/postgres/talks/Next%20generation%20of%20GIN.pdf
 
This indicates some work is being done in this area.
 
Oleg, if you're listening, do you guys have any exiting news regarding this?
 
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