Well,
I need to prevent other users from entering any transaction till I finish
taking reports from my application. All users will be using the same
application, from which this report is supposed to be printed.
If they enter any data, those data also need to be taken into account in this
report. The process is somehow lengthy that starts from arriving some
cumulative value(s) and based on this value, some lengthy process is done. Any
data entered in between will affect this report as well the process we do.
For this same situation, while using SQL Server, we used to count the number of
users of that database and if it's greater than one, we don't start the
process. By checking the same no. of users in vantage point, we could achieve
the required result.
I tried the same way in Postgres, but I could not get the correct connection
list, by using this query.
SELECT pid, datname, usename, application_name, client_hostname, client_port,
backend_start, query_start, query, stateFROM pg_stat_activityWHERE datname =
'databasename'And state = 'active'
I expect this query to add the number, when there is another connection from
one computer. I couldn't get it when I tried this query from PGAdmin and
connected this database from another machine. It's just a connection and no
query was executed from that machine.
I think setting isolation level will not work out. Switching to single user
mode, if available, will be better.
Any ideas ?
Happiness AlwaysBKR Sivaprakash
On Thursday, 27 February, 2020, 04:34:46 pm IST, Ravi Krishna
<srkris...@gmx.com> wrote:
>
> Before taking a few reports, we need to ensure that only one connection is
> made to the database and all other computers need to close the connection to
> that database. This is to prevent any additional entry(ies) that could be
> made during the course of the report taking. This single-user mode is to be
> there till the report is taken and few entries are passed.
>
> How to do it? Is it possible to switch to single-user mode from
> application and back to multi-user mode once the work is completed? Or any
> other solution available?
>
> Happiness Always
> BKR Sivaprakash
>
This concept is outdated. You should set your application to correct isolation
level to get a consistent state.
