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

From: Andreas Joseph Krogh
Subject: Re: Searching GIN-index (FTS) and sort by timestamp-column
Date: ,
Msg-id: VisenaEmail.56.28aa743b723b9d9f.1537fb644d3@tc7-visena
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In response to: Re: Searching GIN-index (FTS) and sort by timestamp-column  (Andreas Joseph Krogh)
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Searching GIN-index (FTS) and sort by timestamp-column  (Andreas Joseph Krogh, )
 Re: Searching GIN-index (FTS) and sort by timestamp-column  (Tom Lane, )
  Re: Searching GIN-index (FTS) and sort by timestamp-column  (Andreas Joseph Krogh, )
   Re: Searching GIN-index (FTS) and sort by timestamp-column  (Andreas Joseph Krogh, )
   Re: Searching GIN-index (FTS) and sort by timestamp-column  (Jeff Janes, )
    Re: Searching GIN-index (FTS) and sort by timestamp-column  (Andreas Joseph Krogh, )
     Re: Searching GIN-index (FTS) and sort by timestamp-column  (Oleg Bartunov, )
      Re: Searching GIN-index (FTS) and sort by timestamp-column  (Andreas Joseph Krogh, )
    Re: Searching GIN-index (FTS) and sort by timestamp-column  (Oleg Bartunov, )
     Re: Searching GIN-index (FTS) and sort by timestamp-column  (Jeff Janes, )
  Re: Searching GIN-index (FTS) and sort by timestamp-column  (Evgeniy Shishkin, )
   Re: Searching GIN-index (FTS) and sort by timestamp-column  (Evgeniy Shishkin, )
    Re: Searching GIN-index (FTS) and sort by timestamp-column  (Evgeniy Shishkin, )
     Re: Searching GIN-index (FTS) and sort by timestamp-column  (Andreas Joseph Krogh, )
     Re: Searching GIN-index (FTS) and sort by timestamp-column  (Tom Lane, )
      Re: Searching GIN-index (FTS) and sort by timestamp-column  (Andreas Joseph Krogh, )
       Re: Searching GIN-index (FTS) and sort by timestamp-column  (Tom Lane, )
    Re: Searching GIN-index (FTS) and sort by timestamp-column  (Andreas Joseph Krogh, )

På onsdag 16. mars 2016 kl. 14:53:04, skrev Andreas Joseph Krogh <>:
På onsdag 16. mars 2016 kl. 14:37:27, skrev Tom Lane <>:
Andreas Joseph Krogh <> 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?
 
--
Andreas Joseph Krogh
CTO / Partner - Visena AS
Mobile: +47 909 56 963
 
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