> On 16 Mar 2016, at 18:04, Evgeniy Shishkin <itparanoia@xxxxxxxxx> wrote: > >> >> 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 > Uh, it works if i cast to bigint explicitly WHERE del.fts_all @@ to_tsquery('simple', 'hi') AND del.folder_id = 1::bigint; results in Index Cond: ((folder_id = '1'::bigint) AND (fts_all @@ '''hi'''::tsquery)) >> >>> >>>> 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
