> On 16 Mar 2016, at 17:52, Evgeniy Shishkin <itparanoia@xxxxxxxxx> wrote: > > >> On 16 Mar 2016, at 16:37, Tom Lane <tgl@xxxxxxxxxxxxx> wrote: >> >> Andreas Joseph Krogh <andreas@xxxxxxxxxx> writes: >>> 1. Why isnt' folder_id part of the index-cond? >> >> Because a GIN index is useless for sorting. > > I don't see how gin inability to return sorted data relates to index condition. > In fact i tried to reproduce the example, > and if i change folder_id to int from bigint, then index condition with folder_id is used > > Index Cond: ((fts_all @@ '''hi'''::tsquery) AND (folder_id = 1)) > Looks like documentation http://www.postgresql.org/docs/9.5/static/btree-gin.html is lying about supporting int8 type > >> >>> 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 >> >> >> -- >> Sent via pgsql-performance mailing list (pgsql-performance@xxxxxxxxxxxxxx) >> To make changes to your subscription: >> http://www.postgresql.org/mailpref/pgsql-performance > -- Sent via pgsql-performance mailing list (pgsql-performance@xxxxxxxxxxxxxx) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-performance
