The role of connection pooling in JSP development process

In today's web programming project using Java, security and the speed of the system are all issues that every developer needs to consider. Especially in the Java Mall development and the development of JSP Mall, the use of connection pool and configuration is more important, why this is said, below our developers to take you in-depth understanding of the Java development process of the connection pool.
Each read and write operation of the database requires a connection, and its access flow is probably as follows:
Applying the data layer to datasource request a database connection
DataSource using database driver to open a database connection
Create a database connection, open a TCP socket
Apply a read/write database
If the connection is no longer needed, close the connection
Close socket
It is easy to infer that opening/closing a database connection is a costly operation. PostgreSQL produces a separate OS process for each client connection, so a high frequency of open/close database connections can increase the pressure on the database management system.
The most obvious reasons for reusing database connections are:
-Reduce OS I/O overhead of creating/destroying TCP connections for application and database management systems
-Reduce JVM Object garbage