Re: Request to share information regarding deadlock in postgresql-9.3.6 - Mailing list pgsql-general

Hello

> -----Original Message-----
> From: pgsql-general-owner@postgresql.org [mailto:pgsql-general-owner@postgresql.org] On Behalf Of Yogesh Sharma
> Sent: Donnerstag, 17. November 2016 08:31
> To: John R Pierce <pierce@hogranch.com>; pgsql-general@postgresql.org
> Subject: Re: [GENERAL] Request to share information regarding deadlock in postgresql-9.3.6
>
> Dear John,
>
> Thanks for sharing solution approaches.
>
> >do each reindex as a seperate transaction so only one table gets locked at a time.
> Transaction is already in separate like REINDEX TABLE table1, REINDEX TABLE  table2 etc..
> But this problem is occurred.
>
> One more question regarding below.
> alter table table1 add constraint fk_key foreign key (id, roll_number) references table2 (id, roll_number) on delete
> restrict on update restrict; It shows below error:
> ERROR:  there is no unique constraint matching given keys for referenced table "table2"

As mentioned upthread, the foreign key must match the primary key (more precisely a unique key) of the table it
references.
Now the primary key of table2 is (id, roll_number, account_id) but you are trying to reference only a part of it.

> references table2 (id, roll_number)
                     ^^^^^^^^^^^^^^^^

You can add a unique contraint in table2:

create table table2
(
   id char(6) not null,
   roll_number varchar(20) not null,
   account_id varchar(20) not null default '-',
   primary key (id, roll_number, account_id),
   unique (id, roll_number)
);

create table table1
(
   id char(6) not null,
   roll_number varchar(20) not null,
   primary key (id, roll_number)
);

alter table table1 add constraint fk_key foreign key (id, roll_number) references table2 (id, roll_number) on delete
restricton update restrict; 

db.localhost=> \d table1
              Table "public.table1"
   Column    |         Type          | Modifiers
-------------+-----------------------+-----------
 id          | character(6)          | not null
 roll_number | character varying(20) | not null
Indexes:
    "table1_pkey" PRIMARY KEY, btree (id, roll_number)
Foreign-key constraints:
    "fk_key" FOREIGN KEY (id, roll_number) REFERENCES table2(id, roll_number) ON UPDATE RESTRICT ON DELETE RESTRICT

Regards
Charles

> Table1 contains below structure:
> create table table1
> (
>    id                                    char(6) not null,
>    roll_number               varchar(20) not null,
> -----
> primary key (id, roll_number)
>
> Table2 contains below structure:
>
> create table table2
> (
>    id                                    char(6) not null,
>    roll_number               varchar(20) not null,
> account_id              varchar(20) not null default '-',
> -----
> primary key (id, roll_number, account_id)
>
> How to resolve this issue?
>
> Regards,
> Yogesh
>
> -----Original Message-----
> From: pgsql-general-owner@postgresql.org [mailto:pgsql-general-owner@postgresql.org] On Behalf Of John R Pierce
> Sent: Thursday, November 17, 2016 12:04 PM
> To: pgsql-general@postgresql.org
> Subject: Re: [GENERAL] Request to share information regarding deadlock in postgresql-9.3.6
>
> On 11/16/2016 6:22 PM, Yogesh Sharma wrote:
> > process 5764 is waiting for relation (table) with OID 16459(table2_primary_key), that table is blocked by process
> 4970 and process 4970 is waiting for a lock on another table, OID 16502(table1), which the first process has a lock
> on.
> > Process 5764: INSERT INTO table2 ( id , roll_number, name) VALUES(
> > '1', '4','abc' ) Process 4970: REINDEX TABLE table1, table2 etc..
> >
> > How to resolve this problem?
>
> don't do reindex when the tables are in use.
>
> or
>
> why does process 5764 have a lock on table 1 while its inserting into table 2?
>
> or
>
> do each reindex as a seperate transaction so only one table gets locked at a time.
>
> --
> john r pierce, recycling bits in santa cruz
>
>
>
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