How to see Amazon RDS (postgres) connection limit?
select * from pg_settings where name='max_connections';
for t2.micro for example we have 87 max connexion
for large.micro 522 i think xD
you have always try t close hibernate session if yu use it to make connexion to databases in order to do some (insertions , reading …)
How too close all connexions to your database ?
u can open your psql terminal or your mysql client like Pgadmin select your database and fire this command :
SELECT pg_terminate_backend(pid) FROM pg_stat_activity WHERE -- don't kill my own connection! pid <> pg_backend_pid() -- don't kill the connections to other databases AND datname = 'mydatabasename' ;
How to kill all connexion (my connexion included)
select pg_terminate_backend(pid) from pg_stat_activity where datname = 'doomed_database'
How to kill all connexion (my connexion included and all other connxeion to other database)
select pg_terminate_backend(pid) from pg_stat_activity
How to select list of active connections to a PostgreSQL database ?
SELECT * FROM pg_stat_activity;
each time we fire a request to read write .. to interact with database we open a connexion , we can explose and depass the limit of our database connexion wich is limited for t2.micro fr example to 87 connexion .
when we get an object from our database we i’ve used hibernate ( create factory session ,session fire the read request commit, close session )
but the problem that connexion is not closed after the close()
Solution (2 ways)
adding to my hibernate.cfg.xml
this property wich is an Hibernate’s own connection pooling algorithm is, however, quite rudimentary
A) <property name="connection.pool_size">10</property>
Just replace the hibernate.connection.pool_size property with connection pool specific settings. This will turn off Hibernate’s internal pool. For example, you might like to use c3p0. or any other third party
so A) became
<property name="hibernate.c3p0.min_size">5</property> <property name="hibernate.c3p0.max_size">20</property> <property name="hibernate.c3p0.timeout">300</property> <property name="hibernate.c3p0.max_statements">50</property> <property name="hibernate.c3p0.idle_test_period">3000</property>