> On 16 Mar 2016, at 17:52, Evgeniy Shishkin <itparan...@gmail.com> wrote:
> 
> 
>> On 16 Mar 2016, at 16:37, Tom Lane <t...@sss.pgh.pa.us> wrote:
>> 
>> 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.
> 
> 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@postgresql.org)
>> To make changes to your subscription:
>> http://www.postgresql.org/mailpref/pgsql-performance
> 



-- 
Sent via pgsql-performance mailing list (pgsql-performance@postgresql.org)
To make changes to your subscription:
http://www.postgresql.org/mailpref/pgsql-performance

Reply via email to