Re: query locks up when run concurrently

From: Adrian Klaver <adrian(dot)klaver(at)aklaver(dot)com>
To: azhwkd <azhwkd(at)gmail(dot)com>
Cc: Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us>, pgsql-general(at)postgresql(dot)org
Subject: Re: query locks up when run concurrently
Date: 2016-11-24 18:14:04
Message-ID: 66381912-9482-c1bd-60e4-c768197036f7@aklaver.com
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On 11/23/2016 10:41 PM, azhwkd wrote:
> The group ID is part of the primary key of the group_history table. My
> understanding is that two INSERTs with different group IDs should not
> collide in this case, or am I wrong in thinking this?

After fresh coffee:

In your first post you had this:
"(In the application this
query is run up to 10 times in parallel with different parameters)"

where the parameters look to be a timestamp and a group id.

Is it possible that the combination of parameters over the 10 different
queries is not actually selecting rows in each result set that are
unique over (group,id,sub_category,"date","hour") between result sets?

>
> The table definition for group_history is the following:
>
> CREATE TABLE public.group_history (
> group int4 NOT NULL,
> id int4 NOT NULL,
> sub_category int4 NOT NULL,
> "date" date NOT NULL,
> aa int8 NOT NULL,
> ab int8 NOT NULL,
> bb int8 NOT NULL,
> ba int8 NOT NULL,
> quantity int8 NOT NULL,
> "hour" int2 NOT NULL,
> CONSTRAINT group_history_pk PRIMARY KEY (group,id,sub_category,"date","hour")
> )
> WITH (
> OIDS=FALSE
> );
>
> Kind regards,
> Sebastian
>

--
Adrian Klaver
adrian(dot)klaver(at)aklaver(dot)com

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