On Sat, Mar 19, 2016 at 5:44 AM, Jeff Janes <jeff.ja...@gmail.com> wrote:
> On Wed, Mar 16, 2016 at 6:53 AM, Andreas Joseph Krogh <andr...@visena.com> > wrote: > >> På onsdag 16. mars 2016 kl. 14:37:27, skrev Tom Lane <t...@sss.pgh.pa.us>: >> >> Andreas Joseph Krogh <andr...@visena.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? >> > > I don't see why it would not be possible to create a new execution node > type that does an index scan to obtain order (or just to satisfy an > equality or range expression), and takes a bitmap (as produced by the > FTS/GIN) to apply as a filter. But, I don't know of anyone planning on > doing that. > Please, find bitmap filtering patch, which we developed several months ago, but failed to find good use case :( Teodor is here now, so he could answer the questions. > > Cheers, > > Jeff >
bitfilter-0.9.patch.gz
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