Java Mybatis3 PoolDataSource as Singletone










0















i made simple program that connect with Postgresql, to select data from database.

i set 5 thread to select database and i use PoolDataSource default setting.

DAO class is singletone, SqlsessionFactory also same, Sqlsession is method scope.



ExecutorService service = Executors.newFixedThreadPool(5);
service.submit(()->
//select each another table
);


and i saw stacktrace in Jconsole.

one thread approach popConnection method in PoolDataSource, another thread was wait.

and one thread approach query execute method in Postgresql, another thread was wait.



i think that database connection must be synchronized.

but only one thread can approach query execute?

there is no way to execute query same time with another thread?

or this cause is PoolDataSource made as singleton?

Thanks.










share|improve this question






















  • Are you positive that threads are waiting for the connection from the pool and not on the response from the DB? Can you share an output of the jstack -p you_process_id which shows this?

    – Roman Konoval
    Nov 16 '18 at 8:33















0















i made simple program that connect with Postgresql, to select data from database.

i set 5 thread to select database and i use PoolDataSource default setting.

DAO class is singletone, SqlsessionFactory also same, Sqlsession is method scope.



ExecutorService service = Executors.newFixedThreadPool(5);
service.submit(()->
//select each another table
);


and i saw stacktrace in Jconsole.

one thread approach popConnection method in PoolDataSource, another thread was wait.

and one thread approach query execute method in Postgresql, another thread was wait.



i think that database connection must be synchronized.

but only one thread can approach query execute?

there is no way to execute query same time with another thread?

or this cause is PoolDataSource made as singleton?

Thanks.










share|improve this question






















  • Are you positive that threads are waiting for the connection from the pool and not on the response from the DB? Can you share an output of the jstack -p you_process_id which shows this?

    – Roman Konoval
    Nov 16 '18 at 8:33













0












0








0








i made simple program that connect with Postgresql, to select data from database.

i set 5 thread to select database and i use PoolDataSource default setting.

DAO class is singletone, SqlsessionFactory also same, Sqlsession is method scope.



ExecutorService service = Executors.newFixedThreadPool(5);
service.submit(()->
//select each another table
);


and i saw stacktrace in Jconsole.

one thread approach popConnection method in PoolDataSource, another thread was wait.

and one thread approach query execute method in Postgresql, another thread was wait.



i think that database connection must be synchronized.

but only one thread can approach query execute?

there is no way to execute query same time with another thread?

or this cause is PoolDataSource made as singleton?

Thanks.










share|improve this question














i made simple program that connect with Postgresql, to select data from database.

i set 5 thread to select database and i use PoolDataSource default setting.

DAO class is singletone, SqlsessionFactory also same, Sqlsession is method scope.



ExecutorService service = Executors.newFixedThreadPool(5);
service.submit(()->
//select each another table
);


and i saw stacktrace in Jconsole.

one thread approach popConnection method in PoolDataSource, another thread was wait.

and one thread approach query execute method in Postgresql, another thread was wait.



i think that database connection must be synchronized.

but only one thread can approach query execute?

there is no way to execute query same time with another thread?

or this cause is PoolDataSource made as singleton?

Thanks.







java multithreading mybatis java-threads






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asked Nov 15 '18 at 1:55









KJ HEYKJ HEY

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  • Are you positive that threads are waiting for the connection from the pool and not on the response from the DB? Can you share an output of the jstack -p you_process_id which shows this?

    – Roman Konoval
    Nov 16 '18 at 8:33

















  • Are you positive that threads are waiting for the connection from the pool and not on the response from the DB? Can you share an output of the jstack -p you_process_id which shows this?

    – Roman Konoval
    Nov 16 '18 at 8:33
















Are you positive that threads are waiting for the connection from the pool and not on the response from the DB? Can you share an output of the jstack -p you_process_id which shows this?

– Roman Konoval
Nov 16 '18 at 8:33





Are you positive that threads are waiting for the connection from the pool and not on the response from the DB? Can you share an output of the jstack -p you_process_id which shows this?

– Roman Konoval
Nov 16 '18 at 8:33












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