6、 Configuration resolution of hikariconfig

Welcome to my blog , Synchronize updates : Fengshan bieyuan

Source code version 2.4.5-SNAPSHOT

Use HikariConfig initialization HikariCP

stay 《HikariCP Initialization analysis of source code analysis 1 》 in , We analyzed HikariCP There are two ways to initialize , It mentions the use of HikariConfig The way ：

HikariConfig config = new HikariConfig();
config.setJdbcUrl("jdbc:mysql://localhost:3306/test");
config.setUsername("root");
config.setPassword("123");
// Set database unique properties 
config.addDataSourceProperty("cachePrepStmts", "true");
// Use HikariConfig structure HikariDataSource
HikariDataSource dataSource = new HikariDataSource(config);
// Get connection from connection pool 
Connection connection = dataSource.getConnection();

Copy

This method is officially recommended , The performance will be improved .HikariConfig In fact, that is HikariCP Configuration class , As we mentioned earlier HikariDataSource Inherited HikariConfig, So we can also use HikariDataSource Direct initialization HikariCP, But the performance of this method is better than that of HikariConfig Slightly worse .

Important configuration

Let's analyze today HikariCP Configuration in , Almost all configurations are HikariConfig in , yes HikariConfig Member variables of . Let's see ：

/*  Can be passed during operation JMX Modified properties  */

   // The maximum waiting time to get a connection from the connection pool ,  Unit millisecond ,  The default value is  30 second ,  At least  250ms
   private volatile long connectionTimeout;
   // Timeout to check if the connection is valid , Unit millisecond ,  Default  5000ms,  Minimum  250ms,  Not greater than connectionTimeout
   //
   private volatile long validationTimeout;
   // The maximum idle time a connection can spend in the pool ,  Unit millisecond ,  At least  10s,  Default  10  minute , 0  Means never time out ,  The configuration cannot be greater than maxLifetime
   private volatile long idleTimeout;
   // Maximum time for connection leak detection ,  Default  0,  The minimum  2000 millisecond ;  in other words ,  The total time from taking out the connection pool to returning the connection pool ,  Not beyond this time , If it exceeds the limit, it will be judged as leakage 
   private volatile long leakDetectionThreshold;
   // Maximum connection lifetime ,  Unit millisecond ,  Minimum allowable value 30000 ms,  Default 30 minute ,  It is recommended that the settings are better than those of the database  wait_timeout  A few minutes 
   private volatile long maxLifetime;
   // The maximum number of connections that can be reserved in the connection pool ,  such as : 100,  The number of connections in the connection pool cannot exceed  100  individual 
   private volatile int maxPoolSize;
   // Minimum number of free connections ,  Default  10  individual ,  in other words ,  A maximum of... Can be reserved in the connection pool  10  Free connections ,  Many will be shut down 
   private volatile int minIdle;

   /*  Properties that cannot be modified at run time  */

   // This property sets a SQL sentence ,  When getting a connection from the connection pool ,  First implement the change  sql,  Verify that the connection is available ,  Example : select 1
   // If it is used  JDBC 4  It is not recommended to configure this option ,  because JDBC 4  Use  ping  command ,  More efficient 
   private String connectionTestQuery;
   // Database driven dataSource Class name ,  And jdbcUrl,  You have to choose between ,  If both are configured ,  Use this attribute first ,  Example  : org.postgresql.ds.PGSimpleDataSource
   private String dataSourceClassName;
   private String dataSourceJndiName;
   // Database driver class ,  And dataSourceClassName No coexistence ,  If this property is configured ,  that jdbcUrl Can't be empty ,  Example : com.mysql.jdbc.Driver
   private String driverClassName;
   // And dataSourceClassName,  You have to choose between ,  If both are configured ,  Ignore this property ,  Example : jdbc:mysql://localhost:3306/simpsons
   private String jdbcUrl;
   // Mandatory ,  Database connection password 
   private String password;
   // Connection pool name ,  Automatically generated by default , Hikari  It is generally used for logging and  JMX  in ,  If there are more than one  Hikari  Connection pool ,  It is recommended to configure a meaningful name 
   private String poolName;
   private String transactionIsolationName;
   // Mandatory ,  Database connection user name 
   private String username;
   // Auto commit transaction ,  The default value is true
   private boolean isAutoCommit;
   // Controls whether connections obtained from the pool are read-only ,  The database needs to support read-only mode 
   private boolean isReadOnly;
   // The default value is true, Whether to fail quickly , That is, create a connection during startup to verify whether there are errors in key parameters , If the connection cannot be established , Throw an error immediately , It is convenient for users to find problems in time 
   private boolean isInitializationFailFast;
   //
   private boolean isIsolateInternalQueries;
   // Automatic registration  JMX  dependent  bean,  Used to modify connection pool settings at runtime 
   private boolean isRegisterMbeans;
   // Whether to allow JMX  Suspend connection pool 
   private boolean isAllowPoolSuspension;
   // Users directly specify dataSource example ,  Don't use  Hikari  Created instance 
   private DataSource dataSource;

Copy

Not all of the above attributes , Some of the less important attributes we ignore .

HikariConfig The configuration of can be divided into two parts ： Can be modified at run time , Not modifiable during runtime .

The operation period can be modified

Property name	meaning	remarks
connectionTimeout	The maximum waiting time to get a connection from the connection pool	The default value is 30 second , At least 250ms
validationTimeout	Timeout to check if the connection is valid	Default 5000ms, Minimum 250ms, Not greater than connectionTimeout
idleTimeout	The maximum idle time a connection can spend in the pool	At least 10s, Default 10 minute , 0 Means never time out , The configuration cannot be greater than maxLifetime
leakDetectionThreshold	Maximum time for connection leak detection	Default 0 Indicates that... Is not enabled , The minimum 2000 millisecond
maxLifetime	Maximum connection lifetime	Minimum allowable value 30000 ms, Default 30 minute , It is recommended that the settings are better than those of the database wait_timeout A few minutes
maxPoolSize	The maximum number of connections that can be reserved in the connection pool
minIdle	Minimum number of free connections	Default 10 individual

The so-called runtime modifiable properties , It can be used JMX Directly modifying , We will have a 《HikariCP Source code analysis access connection process 2 》 The usage recommended by the author is mentioned in , You can have a look .

The operation period cannot be modified

Property name	meaning	remarks
connectionTestQuery	Verify that the connection is available sql	Example : select 1, If it is used JDBC 4 It is not recommended to configure this option , because JDBC 4 Use ping command , More efficient
dataSourceClassName	Database driven dataSource Class name	And jdbcUrl, You have to choose between , If both are configured , Use this attribute first , Example : org.postgresql.ds.PGSimpleDataSource
driverClassName	Database driver class	And dataSourceClassName No coexistence , If this property is configured , that jdbcUrl Can't be empty , Example : com.mysql.jdbc.Driver
jdbcUrl	url	And dataSourceClassName, You have to choose between , If both are configured , Ignore this property , Example : jdbc:mysql://localhost:3306/simpsons
password	Database connection password
username	Database connection user name
isRegisterMbeans	Automatic registration JMX dependent bean	Used to modify connection pool settings at runtime
isAllowPoolSuspension	Whether to allow JMX Suspend connection pool

It is worth mentioning that , If you want to use JMX Modify the runtime configuration , Must be configured isRegisterMbeans and isAllowPoolSuspension.

In fact, the more important ones are the configurations that can be modified at runtime , Just figure out what they mean , You can modify it according to your own situation .