Re: Parallel Insert and Delete operation

It is also possible that you will get a foreign key violation exception on
the process inserting into table 2, but you will not get database
inconsistency.

On Wed, Oct 31, 2012 at 9:33 AM, Albe Laurenz <laurenz(dot)albe(at)wien(dot)gv(dot)at>wrote:

> Yelai, Ramkumar IN BLR STS worte:
> > Sent: Wednesday, October 31, 2012 12:40 PM
> > To: pgsql-general(at)postgresql(dot)org
> > Subject: [GENERAL] Parallel Insert and Delete operation
> >
> > Hi All,
> >
> > Please clarify me the following example.
> >
> > I have 2 tables
> >
> > Table1 - ( it has one primary key and few columns )
> > Table2 - ( it has one primary key and few columns. It has one
> foreign key, which refers table1
> > primary key ).
> >
> > I have 2 operations, which are written in pl/pgsql procedure.
> >
> > Operation1() - Inserts the records to table2 at every hour basis.
> > Operation2() - Delete the records from Table 1 and Table2 based on the
> primary key.
> >
> > What if both operations are running at the time for the same primary
> key.
> >
> > what I have to take care to run these two operations perfectly without
> creating inconsistency in
> > database.
>
> With the foreign key in place there can be no entry in table2
> that does not have a corresponding entry in table1.
>
> Concurrency is solved with locks, so one of the concurrent
> operations might have to wait until the other one is done.
>
> That is handled by the database system automatically.
>
> Yours,
> Laurenz Albe
>
>
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--
Moshe Jacobson
Nead Werx, Inc. | Senior Systems Engineer
2323 Cumberland Parkway, Suite 201 | Atlanta, GA 30339
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