| From: | Thomas Munro <thomas(dot)munro(at)enterprisedb(dot)com> |
|---|---|
| To: | Amit Kapila <amit(dot)kapila16(at)gmail(dot)com> |
| Cc: | Kuntal Ghosh <kuntalghosh(dot)2007(at)gmail(dot)com>, Pg Hackers <pgsql-hackers(at)postgresql(dot)org> |
| Subject: | Re: Parallel Index Scan vs BTP_DELETED and BTP_HALF_DEAD |
| Date: | 2017-12-13 03:20:04 |
| Message-ID: | CAEepm=2pJAqCrcG-QVLjwSJua33AU7Z7pWVjQGXWse3rMZHG7g@mail.gmail.com |
| Views: | Raw Message | Whole Thread | Download mbox | Resend email |
| Thread: | |
| Lists: | pgsql-hackers |
On Wed, Dec 13, 2017 at 3:41 PM, Amit Kapila <amit(dot)kapila16(at)gmail(dot)com> wrote:
> Good. I hope that the patch I have posted above is able to resolve
> this problem. I am asking as you haven't explicitly mentioned that.
I can confirm that your patch fixes the problem for forward scans.
That is, I can see it reaching the BTP_DELETED case via an extra LOG
statement I added, and it worked correctly. Good.
I don't know how to make it hit the backwards scan case. I can get a
backward scan in a worker by changing the query to "select count(*)
from (select * from jobs where id + 1 > id order by status desc) ss"
but I suspect that _bt_walk_left() may be hiding deleted pages from us
so the condition may not be reachable with this technique.
--
Thomas Munro
http://www.enterprisedb.com
| From | Date | Subject | |
|---|---|---|---|
| Next Message | Andres Freund | 2017-12-13 03:24:29 | pg_ctl on windows can't open postmaster.pid: Permission denied |
| Previous Message | Haribabu Kommi | 2017-12-13 02:50:12 | Re: [HACKERS] Refactor handling of database attributes between pg_dump and pg_dumpall |