Re: How to get updated order data

On Thu, 2022-04-07 at 16:16 +0300, Andrus wrote:
> Orders are in table
>
>          create table order (
>            dokumnr int primary key,
>            packno char(10)
>            );
>         insert into order dokumnr values (123);
>
>  One user sets pack number using
>
>      update order set packno='Pack1' where dokumnr=123
>
>  3 seconds later other user retrieves pack number using
>
>      select packno from order where dokumnr=123
>
>  However, other user gets null value, not Pack1 as expected. After some time later, correct value Pack1 is returned.
>
>  How to get updated data from other user immediately?
>  3 seconds is long time, it is expected that select suld retrieve update data.
>
>  There are lot of transactions running concurrently. Maybe update command is not written to database if second user retrieves it.
>
>  How to flush orders table so that current results are returned for second user select ?
>
>  Using 
>   PostgreSQL 13.2, compiled by Visual C++ build 1914, 64-bit
>   and psqlODBC driver.

That cannot happen, unless

a) the UPDATE runs in a transaction that hasn't been committed

b) the SELECT is running on a standby server, and there is replication lag

Yours,
Laurenz Albe

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