DBCP - validationQuery for different Databases

bugs_ picture bugs_ · May 21, 2012 · Viewed 63.7k times · Source

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).

Answer

bugs_ picture bugs_ · May 21, 2012

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?