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

From: Andreas Joseph Krogh <andreas(at)visena(dot)com>
To: pgsql-performance(at)postgresql(dot)org
Subject: Re: Searching GIN-index (FTS) and sort by timestamp-column
Date: 2016-03-16 13:53:04
Message-ID: VisenaEmail.55.5cac9849d07151e7.1537fb2771f@tc7-visena
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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.
 
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