On Fri, Apr 8, 2022 at 2:26 PM Laurenz Albe <laurenz.a...@cybertec.at> wrote:
> 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 > There's also: c) The SELECT runs in a transaction stat *started* before the transaction that a runs in. (Assuming it then retries with a new transaction later, that is) -- Magnus Hagander Me: https://www.hagander.net/ <http://www.hagander.net/> Work: https://www.redpill-linpro.com/ <http://www.redpill-linpro.com/>
