Thread: CannotAcquireResourceException in Junit

> On Jan 24, 2018, at 9:57 AM, Abhra Kar <abhra.kar@gmail.com> wrote:
>
>
> Hi,
>          I am getting the following error while running bunch of Junit test cases through “ant test” command----
>  Caused by: com.mchange.v2.resourcepool.CannotAcquireResourceException: A ResourcePool could not acquire a resource
fromits primary factory or source.  
> PFA full stack trace.
>
> After execution of 300 test cases I got this error. The setup() method code snippet is ---
>
> @Before
>     public void setUp() throws Exception {
>         entityManager = entityManagerFactory.createEntityManager();//javax.persistence.EntityManager
>         entityManager.getTransaction().begin();
> }
>
> this method ran for all 300 test cases but didn’t get error .
>
> Another 900 test cases are remaining. I tried running single test cases from those test cases, getting same error for
all.
> What is root cause of this error.
>
> Thanks and Regards,
> Abhra
> <StackTrace.doc>
Apparently Merlin is busy elsewhere.  You need to name the OS, the postgres version, and the stack you’re using.

But my guess is you’re not closing those connections and have hit a configuration limit for maximum connection.

> On Jan 24, 2018, at 9:32 PM, Abhra Kar <abhra.kar@gmail.com> wrote:
>
> Thanks Rob.
>
> OS -- RHEL 6.7(Santiago)
> Postgres Version -- 9.5
> Location --/usr/pgsql-9.5/bin/psql
>
> Can you please guide me , how to stop all those connection manually(From psql prompt or linux shell or any .sh file
within postgres directory) 
>
> Regards,
> Abhra
>
> On Thu, Jan 25, 2018 at 9:36 AM, Rob Sargent <robjsargent@gmail.com> wrote:
>
> > On Jan 24, 2018, at 9:57 AM, Abhra Kar <abhra.kar@gmail.com> wrote:
> >
> >
> > Hi,
> >          I am getting the following error while running bunch of Junit test cases through “ant test” command----
> >  Caused by: com.mchange.v2.resourcepool.CannotAcquireResourceException: A ResourcePool could not acquire a resource
fromits primary factory or source. 
> > PFA full stack trace.
> >
> > After execution of 300 test cases I got this error. The setup() method code snippet is ---
> >
> > @Before
> >     public void setUp() throws Exception {
> >         entityManager = entityManagerFactory.createEntityManager();//javax.persistence.EntityManager
> >         entityManager.getTransaction().begin();
> > }
> >
> > this method ran for all 300 test cases but didn’t get error .
> >
> > Another 900 test cases are remaining. I tried running single test cases from those test cases, getting same error
forall. 
> > What is root cause of this error.
> >
> > Thanks and Regards,
> > Abhra
> > <StackTrace.doc>
> Apparently Merlin is busy elsewhere.  You need to name the OS, the postgres version, and the stack you’re using.
>
> But my guess is you’re not closing those connections and have hit a configuration limit for maximum connection.
>
>
>
Please don’t top post in the forum.

Something like this from
https://stackoverflow.com/questions/5408156/how-to-drop-a-postgresql-database-if-there-are-active-connections-to-it

 You might want a bunch of
select pg_terminate_backend(<pick one pid you no is yours from ps output>);


WARNING: this kills all connections.
SELECT pg_terminate_backend(pg_stat_activity.pid)
FROM
 pg_stat_activity
WHERE pg_stat_activity.datname = 'TARGET_DB'
AND pid <> pg_backend_pid();

On Tue, 2018-01-30 at 15:41 +0530, Abhra Kar wrote:
> Hi,
>        Sorry for late reply. Below options I tried --- 
> 1>pg_terminate_backend --> Successful execution.
> 2> Increase max_connection to 900 in
> /var/lib/pgsql/9.5/data/postgresql.conf .After modify restart psql
> service--- 
> service postgresql-9.5 start
> service postgresql-9.5 stop
> 
> Then execute select * from pg_stat_activity it shows 2 connections.
> 
> 
> 3>set cp3p0 options ----           
> com.mchange.v2.c3p0.ComboPooledDataSource cpds = new
> ComboPooledDataSource();
>   cpds.setMaxPoolSize(1000);
>             cpds.setMaxStatements(0);
>             cpds.setInitialPoolSize(50);
>             cpds.setAcquireIncrement(5);
>             cpds.setAcquireRetryAttempts(5);
> 
> 
> But the problem still persist.Please provide suggestion.
> 
> Regards,
> Abhra
> 



The stack trace you sent with your original post shows hibernate
crashing as it has no connection string.
You are using hibernate as the go between the RDBMS and your app.
The problem is more than likely in your c3p0 package.
I haven't a clue what it is supposed to do, but my guess is that the
faulty code is there, not with your configuration parameters.

My 0.02 worth.
HTH,
Rob