Re: R: Problem with row-level lock

On 6/21/19 1:40 AM, Job wrote:
> Dear Adrian,
>
> thank you for the reply!
>
>>> i am struggling with a problem due, sometime, to a double concurrent update on the same row of a table.
>
>> What is the error message you get?
>
> We have no error, but the two queries, in "Lock wait", keep stucked for some minutes before completed.
> Are there any parameters useful to "serialize" in some way two different Update queries - for the same field in the same row - arriving concurrently?
>
> I was looking at the lock_timeout parameter: could it be what i am looking for?

If I understood your OP you do not have control of what the client,
correct? If that is the case it makes what you want to achieve more
difficult. To understand what can be done you will want to take a look at:

The locking choices in Postgres.
https://www.postgresql.org/docs/11/mvcc.html

The lock timeouts available(though I don't think they apply to your case)
https://www.postgresql.org/docs/11/runtime-config-locks.html

How to change the transaction modes
https://www.postgresql.org/docs/11/sql-set-transaction.html

>
> Thank you!
> Franco
>

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