connection-pooling

问题 I have a webservice with Java Servlets on a Tomcat server. In my Servlet I use a database pool like this: envContext = new InitialContext(); DataSource ds = (DataSource) envContext.lookup( "java:/comp/env/jdbc/Database" ); con = ds.getConnection(); For initialisation I have this in my web.xml: <resource-ref> <description>DB Connection</description> <res-ref-name>jdbc/Database</res-ref-name> <res-type>javax.sql.DataSource</res-type> <res-auth>Container</res-auth> </resource-ref> Then there is

问题 I'm finding that I'm having some website connection pool issues and I'm in the process of tracking them down. I know one thing to look for is to make sure that any SQLDataReaders get closed and I've gone though and made sure they are. One question that popped up in my head was about methods that return SQLDataReaders and how they get closed (or not). So here's how I have things setup and some example methods: public static SqlDataReader ExecuteReader(SqlCommand cmd) { SqlConnection c = new

问题 I'm relatively very new to this, but I have a Tomcat cluster set up (using mod_proxy from httpd) with session replication (separate redis server) for fault-tolerance. I have a couple of questions about this setup: My application (spring/hibernate) has a different database per user. So the problem here is that the data source (using spring along with hibernate for persistence) is created at Tomcat level. Thus, whatever connection pooling I do will be at server level. As per the cluster

问题 What is the correct usage pattern of HTablePool? I mean, assume that I have my DAO which is initialised with an instance of HTablePool. This DAO is a member instance of a Stateless Session Bean so it is reused between invocations. What is the correct usage beween the following? private HTableInterface aTable; public XYZDAO(final HTablePool pool) { this.aTable = pool.getTable(...); } public void doSomething(...) { aTable.get(...) } or HTablePool should be used like a Datasource and therefore

问题 I have the following code, If I use conn == null in finally do I still use connection pooling? I know it is a good practice to close your connection but how about disposing the whole connection object? public void ExecuteNonQuery(SqlCommand Cmd) { //========== Connection ==========// SqlConnection Conn = new SqlConnection(strConStr); try { //========== Open Connection ==========// Conn.Open(); //========== Execute Command ==========// Cmd.Connection = Conn; Cmd.CommandTimeout = 180; Cmd

问题 We are facing APPARENT DEADLOCK while using c3p0 0.9.5.1 ( which is latest version of c3p0). following is the connection pool config we are using. p:driverClass="${app.jdbc.driverClassReplica}" p:jdbcUrl="jdbc:mysql://database,database/dbname" p:acquireIncrement="5" p:idleConnectionTestPeriod="300" p:maxPoolSize="100" p:maxStatements="2000" p:minPoolSize="10" p:maxIdleTime="1800" p:maxConnectionAge="3600" p:maxIdleTimeExcessConnections="20" p:numHelperThreads="15" p:preferredTestQuery="SELECT

问题 Can a SPID be used by two connections, while both connections are open? If a connection is returned to a connection pool, will it hold on to the SPID? 回答1: Can a SPID be used by two connections, while both connections are open? No, each open connection will have its own SPID. If a connection is returned to a connection pool, will it hold on to the SPID? Yes, as long as the connection is open, it will be associated with one SPID. You can test this yourself by querying sys.sysprocesses .

问题 I'm about to begin my first project with java Let me tell how I used to handle these things... So far now, I've been workin on asp with a com+ componente made with VB6. The component is registered via the com+ administration console with a domain user, something lile my_company_domain\my_app_account The components reads the configuration from an udl file, configured to access the DB with integrated security. I invoke the componente from asp with server.createobject, the component runs with

问题 Communicate with the database in java, we often follow these steps: load a driver get a connection create a Statement or PreparedStatement get the ResultSet close the connection I am confused that we should close connection, all say that create a connection is expensive, so why we can't do like this: static { try { connection = DriverManager.getConnection(connectorURL, user, password); } catch (SQLException e) { e.printStackTrace(); } } We just create a connection as a singleton, and use it

问题 I've got a minimal Spring webapp deployed to Tomcat 7.0.22 - it consists of a couple of pages, a controller, a service, and a DAO which has one method that runs a SELECT query. The webapp is configured to use the new Tomcat JDBC connection pool - here is the resource configuration in the webapp's context.xml: <Resource name="jdbc/myDB" auth="Container" type="javax.sql.DataSource" driverClassName="oracle.jdbc.OracleDriver" url="jdbc:oracle:thin:@blah blah" factory="org.apache.tomcat.jdbc.pool