Re: Partial match fix for fast scan - Mailing list pgsql-hackers

From Fabrízio de Royes Mello
Subject Re: Partial match fix for fast scan
Date
Msg-id CAFcNs+q=1JiHihBkq-VtQHWBTyxuRdB=iz2VLC-6LmQ2ifizPg@mail.gmail.com
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In response to Partial match fix for fast scan  (Alexander Korotkov <aekorotkov@gmail.com>)
Responses Re: Partial match fix for fast scan
List pgsql-hackers

On Thu, Apr 10, 2014 at 11:09 AM, Alexander Korotkov <aekorotkov@gmail.com> wrote:
Hi,

GIN partial match appears to be broken after fast scan. Following simple test case raises assertion failure.

create extension btree_gin;
create table test as (select id, random() as val from generate_series(1,1000000) id);
create index test_idx on test using gin (val);
vacuum test;
select * from test where val between 0.1 and 0.9;

Attached patch fixes bugs in entryGetItem function.
I would especially point that "continue;" checks "while" condition even if it's postfix "while". That's why I surrounded tbm_iterate with another "while".


Interesting... to me (using current master) your test case doesn't fail...

fabrizio=# select * from test where val between 0.1 and 0.9;
   id   |        val       
--------+-------------------
      1 | 0.554413774050772
      2 | 0.767866868525743
      3 | 0.601187175605446
...


But fail if I change the values of between clause:

fabrizio=# select * from test where val between 0.1 and 0.19;
ERROR:  tuple offset out of range: 8080


Regards,

--
Fabrízio de Royes Mello
Consultoria/Coaching PostgreSQL

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