Re: BUG #14973: hung queries

On Tue, Dec 19, 2017 at 6:38 AM, Thomas Munro
<thomas(dot)munro(at)enterprisedb(dot)com> wrote:
> On Fri, Dec 15, 2017 at 1:31 AM, <skaurus(at)gmail(dot)com> wrote:
>> pg_stat_activity says that they all have wait_event_type = IPC, wait_event =
>> BtreePage, state = active
>
> https://www.postgresql.org/message-id/E1ePESn-0005PV-S9%40gemulon.postgresql.org
>
> The problem is in Parallel Index Scan for btree. The fix will be in
> 10.2. One workaround in the meantime would be to disable parallelism
> for that query (SET max_parallel_workers_per_gather = 0).

On second thoughts, a more targeted workaround to avoid just these
buggy parallel index scans without disabling parallelism in general
might be:

SET min_parallel_index_scan_size = '5TB';

(Assuming you don't have any indexes that large.)

--
Thomas Munro
http://www.enterprisedb.com