Configuration of c3p0 in hibernate

The following configurations are available in hibernate. cfg. xml.
<Property name = "hibernate. Connection. provider_class"> org. hibernate. Connection. c3p0connectionprovider </property> perty name = "hibernate. c3p0. acquireretryattempts"> 30 </property>
<Property name = "hibernate. c3p0. acquireincrement"> 2 </property>
<Property name = "hibernate. c3p0. checkouttimeout"> 30000 </property>
<Property name = "hibernate. c3p0. idleconnectiontestperiod"> 120 </property>
<Property name = "hibernate. c3p0. maxidletime"> 180 </property>
<Property name = "hibernate. c3p0. initialpoolsize"> 3 </property>
<Property name = "hibernate. c3p0. maxpoolsize"> 50 </property>
<Property name = "hibernate. c3p0. minpoolsize"> 1 </property>
<Property name = "hibernate. c3p0. maxstatements"> 0 </property>

Then, the number of connections with initialpoolsize = 3 will be created each time during use. If you refresh multiple times, the too connector CTS error is reported. I have been surfing the internet for a long time and I don't know why. Only one similar problem description is found on javaeye.
Later, I read the official documents of c3p0 to find the reason.
Solution: delete this configuration! Because it cannot be configured here. If necessary, you can configure it through the c3p0 configuration file.
Official documentation:

C3p0-native property name	Hibernate configuration key
C3p0. acquireincrement	Hibernate. c3p0. acquire_increment
C3p0. idleconnectiontestperiod	Hibernate. c3p0. idle_test_period
C3p0. initialpoolsize	Not available -- uses minimum size
C3p0. maxidletime	Hibernate. c3p0. Timeout
C3p0. maxpoolsize	Hibernate. c3p0. max_size
C3p0. maxstatements	Hibernate. c3p0. max_statements
C3p0. minpoolsize	Hibernate. c3p0. min_size
C3p0. testconnectionsoncheckout	Hibernate. c3p0. Validate Hibernate 2.x only!

Remember --
These, andOnly these, Properties must be defined in your hibernate configuration,
Or else they will be set to hibernate-specified defaults. All other configuration properties that you wish to set shoshould be defined in
C3p0. PropertiesFile. (See
"Overriding c3p0 defaults via c3p0. properties ".)

Note:

1. C3p0. initialpoolsize	Not available -- uses minimum size

Note: This configuration cannot be configured in hibernate. It uses minpoolsize.
2.These, andOnly these, Properties must be defined in your hibernate configuration,
In hibernateOnly and requiredConfigure these attributes.

Many configuration documents provided on the Internet are incorrect or nonstandard! No one raised this question for some reason. It is estimated that it was copied.
In addition, the following statements are incorrect when you configure these attributes in hibernate! Or non-standard.
<Property name = "hibernate. c3p0. acquireretryattempts"> 30 </property>
<Property name = "hibernate. c3p0. acquireincrement"> 2 </property>
<Property name = "hibernate. c3p0. idleconnectiontestperiod"> 120 </property>
<Property name = "hibernate. c3p0. maxidletime"> 180 </property>
<Property name = "hibernate. c3p0. maxpoolsize"> 50 </property>
<Property name = "hibernate. c3p0. minpoolsize"> 1 </property>
<Property name = "hibernate. c3p0. maxstatements"> 0 </property>
After testing, three connections are created for each query. Why? Initialization is not configured hereInitialpoolsizeValue?
Initialpoolsize
The default value is 3, so three connections are created each time? This is probably the problem.

Therefore, it is well-behaved to use official writing. As to why the number of initialization will be created each time (or the number will be initialized once every query), it is unclear whether it is a problem with my code or cp30 .) Have time to investigate.