当数据库连接中断时，如何对 Oracle 和 grails 项目进行自动池重新连接？

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. Answers to this question are eligible for a +50 reputation bounty. Dashzeveg Galbadrakh wants to to this question.

I have a project that used a grails framework 3.X and Oracle DB, and the project is deployed on tomcat 9.0.X.

There is a DB connection problem on the project that the DB connection is interrupted and then the project can't reconnect with the DB automatically when the connection, firewall or any network configuration between the project and DB has changed; or the settings of the DB have changed or the DB has restarted. Because of that, nowadays, I manually redeploy the project on a tomcat sever when this problem is happening.

In order to fix the problem, I tried many changes, but the issue hasn't disappeared yet. For example, I changed properties of a dataSource configuration on application.yml and tried different versions of OJDBC driver.

The interrupted connection can reconnect automatically when I changed the value of "pool" to false from true on application.yml. But, I think that "pool: false" configuration has negative consequences because a DB connection operation is an expensive. For instance, to reach a maximum connection limit, ...

So, my question is that how to do an automatic pooled reconnection on an Oracle DB and a grails project when a DB connection is interrupted?

My current configuration on application.yml (maybe some properties are changed because of the test):

dataSources:
    dataSource:
        pooled: true
        jmxExport: true
        driverClassName: oracle.jdbc.OracleDriver

environments:
    development:
        dataSources:
            dataSource:
                logSql: false
                dbCreate: update
                url: jdbc:oracle:thin:@localdomain:1521/test
                username: test
                password: test
                properties:
                    maxActive: 50
                    maxIdle: 25
                    minIdle: 1
                    initialSize: 5
                    numTestsPerEvictionRun: 3
                    maxWait: 1000
                    testOnBorrow: true
                    testWhileIdle: true
                    testOnReturn: true
                    minEvictableIdleTimeMillis: 1000
                    timeBetweenEvictionRunsMillis: 1000
                    validationQuery: SELECT 1 FROM DUAL
                    validationQueryTimeout: 5
                    validationInterval: 5
                    removeAbandoned: true
                    removeAbandonedTimeout: 5
    production:
        dataSources:
            dataSource:
                dbCreate: none
                jndiName: "java:comp/env/testDs"
                properties:
                    maxActive: 50
                    maxIdle: 25
                    minIdle: 1
                    initialSize: 5
                    numTestsPerEvictionRun: 3
                    maxWait: 1000
                    testOnBorrow: true
                    testWhileIdle: true
                    testOnReturn: true
                    minEvictableIdleTimeMillis: 1000
                    timeBetweenEvictionRunsMillis: 1000
                    validationQuery: SELECT 1 FROM DUAL
                    validationQueryTimeout: 5
                    validationInterval: 5
                    removeAbandoned: true
                    removeAbandonedTimeout: 5

Answer 1

you can try set validationQuery properties is null, check validationQuery properties is confilct other properties.