java - Does Mysql execute statement synchronously in one connection? -

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connection connection = drivermanager.getconnection("jdbc:mysql://localhost:3306/","root", "password");

let's in java, can create mysql connection via code above. connection object, can create few statement objects below:

statement = connection.createstatement();

i know, if execute statement object (by calling statement.executequery) in different threads, execute synchronously or asynchronously in mysql database? because know is, 1 connection in mysql handled 1 thread, thinking is, statements created connection schedule in queue. correct?

so, if have servlet below:

public class helloservlet extends httpservlet {     connection connection = drivermanager.getconnection("jdbc:mysql://localhost:3306/","root", "password");        public void doget(httpservletrequest request, httpservletresponse response)                throws ioexception, servletexception {      statement = connection.createstatement();    } }

from code above, if there more 1 user connect servlet @ same time, block each other because statement cannot execute parallel @ same time? so, have wait previous statement finish executing before turn take on? way avoid kind of problem?

because know is, 1 connection in mysql handled 1 thread, thinking is, statements created connection schedule in queue.

you should not hold database connection open database. should use connection pool apache's dbcp , connection, execute query or other sql, , release connection pool.

if there more 1 user connect servlet @ same time, block each other because statement cannot execute parallel @ same time? so, have wait previous statement finish executing before turn take on?

right. if have 1 user making database transaction, thread cannot use same connection database @ same time.

public class helloservlet extends httpservlet {      connection connection = drivermanager.getconnection("j...");

yeah, should not create connection field servlet class this. open tcp connection database , hold life of application. these connections time out or closed because of network issues need kept alive , on occasion reopened. of handled dbcp or other connection pools.


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