问题
I use DBCP pool and I want use testOnBorrow and testOnReturn to test if connection is still valid.
Unfortunately I have to set property validationQuery to make it work.
Question: What value should be in validationQuery?
I know, that: validationQuery must be an SQL SELECT statement, that returns at least one row.
Problem is that we use various databases (DB2, Oracle, hsqldb).
回答1:
There is not only one validationQuery for all databases. On each database you have to use different validationQuery.
After few hours of googling and testing I have collected this table:
Database validationQuery notes
- hsqldb -
select 1 from INFORMATION_SCHEMA.SYSTEM_USERS - Oracle -
select 1 from dual - DB2 -
select 1 from sysibm.sysdummy1 - mysql -
select 1 - microsoft SQL Server -
select 1(tested on SQL-Server 9.0, 10.5 [2008]) - postgresql -
select 1 - ingres -
select 1 - derby -
values 1 - H2 -
select 1 - Firebird -
select 1 from rdb$database
I wrote about it on my blog - validation query for various databases.
In advance there is an example of class, which return validationQuery according to JDBC driver.
Or does anybody have better solution?
回答2:
For MySQL with the Connector/J driver, there's a lightweight validation query that just sends a ping to the server and returns a dummy result set. The validation query can be (or should start with) exactly the following string:
/* ping */
For more infor refer to the Validating Connections in the MySQL driver manual
回答3:
For Informix, The validation query is, select 1 from systables
来源：https://stackoverflow.com/questions/10684244/dbcp-validationquery-for-different-databases