如何使Spring Boot自动重新连接到PostgreSQL? [英] How do I get Spring Boot to automatically reconnect to PostgreSQL?

问题描述

我正在运行连接到PostgreSQL数据库的Spring Boot.我已经验证了如果在数据库之后启动Spring Boot，则数据已写入数据库.

I am running Spring Boot connecting to a PostgreSQL database. I have verified that data is written to the database if Spring Boot is started after the database.

spring.datasource.url = jdbc:postgresql://localhost/dbname
spring.datasource.username = user
spring.datasource.password = secret
spring.datasource.driver-class-name = org.postgresql.Driver
spring.datasource.testOnBorrow=true
spring.datasource.validationQuery=SELECT 1

当开发中的数据库发生更改时，我会遇到异常: PreparedStatementCallback; SQL []; This connection has been closed.; nested exception is org.postgresql.util.PSQLException: This connection has been closed.

When there are changes in the database in development, I run into exceptions: PreparedStatementCallback; SQL []; This connection has been closed.; nested exception is org.postgresql.util.PSQLException: This connection has been closed.

请注意，发生异常时，可以再次访问数据库；我认为问题在于连接是陈旧的，因为它最初连接的数据库端点由于重新启动而不再可用.重新启动Spring Boot可以解决该问题.

Note that the database is accessible again when the exceptions occur; I think the problem is that connection is stale because the database endpoint it originally connected to is no longer available because of the restart. Restarting Spring Boot resolves the issue.

如何配置Spring Boot使其重新连接到PostgreSQL，而无需重新启动它?

How do I configure Spring Boot to reconnect to PostgreSQL so that I do not need to restart it?

我试图按照 Spring Boot JPA中的答案-配置自动重新连接和如何在连接时重新连接数据库jpa春季关闭?.我不确定PostgreSQL的行为是否与MySQL不同.我阅读了 Spring Boot文档没有帮助；我不了解所描述的组件，不足以理解我应该查看的文档.

I have attempted to follow the answers in Spring Boot JPA - configuring auto reconnect and How to reconnect database if the connection closed in spring jpa?. I am not sure whether the PostgreSQL behavior is different from MySQL. My reading of the Spring Boot documentation has not helped; I do not know the components described well enough to understand what documentation I should be looking at.

推荐答案

应该将Spring Boot配置为自动重新连接，问题是它不知道断开的连接.

Spring boot should be configured to reconnect automatically, problem is that it is not aware of the broken connection.

由于您已经在借用和验证查询中使用测试，因此只需尝试减少验证间隔，以便每次执行.

Since you are already using test on borrow and validation query, just try reducing validation interval so it is executed every time.

spring.datasource.tomcat.test-on-borrow=true
spring.datasource.tomcat.validation-query=SELECT 1
spring.datasource.tomcat.validation-interval=0

testOnBorrow上的

Tomcat jdbc连接池:

(布尔值)指示在从池中借用对象之前是否先对其进行验证.如果对象验证失败，它将被从池中删除，我们将尝试借用另一个对象.注–要使真值有效，必须将validationQuery或validatorClassName参数设置为非空字符串. 为了获得更有效的验证，请参阅validationInterval .默认值为false

(boolean) The indication of whether objects will be validated before being borrowed from the pool. If the object fails to validate, it will be dropped from the pool, and we will attempt to borrow another. NOTE - for a true value to have any effect, the validationQuery or validatorClassName parameter must be set to a non-null string. In order to have a more efficient validation, see validationInterval. Default value is false

但是要注意validationInterval:

(长整数)避免过多的验证，最多只能在此频率下运行验证-时间以毫秒为单位. 如果要进行验证的连接已在此间隔内经过验证，则将不再进行验证.默认值为30000(30秒).

(long) avoid excess validation, only run validation at most at this frequency - time in milliseconds. If a connection is due for validation, but has been validated previously within this interval, it will not be validated again. The default value is 30000 (30 seconds).

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